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1 | .. _messaging: |
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1 | .. _messaging: | |
2 |
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2 | |||
3 | ====================== |
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3 | ====================== | |
4 | Messaging in IPython |
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4 | Messaging in IPython | |
5 | ====================== |
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5 | ====================== | |
6 |
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6 | |||
7 |
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7 | |||
8 | Introduction |
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8 | Introduction | |
9 | ============ |
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9 | ============ | |
10 |
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10 | |||
11 | This document explains the basic communications design and messaging |
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11 | This document explains the basic communications design and messaging | |
12 | specification for how the various IPython objects interact over a network |
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12 | specification for how the various IPython objects interact over a network | |
13 | transport. The current implementation uses the ZeroMQ_ library for messaging |
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13 | transport. The current implementation uses the ZeroMQ_ library for messaging | |
14 | within and between hosts. |
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14 | within and between hosts. | |
15 |
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15 | |||
16 | .. Note:: |
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16 | .. Note:: | |
17 |
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17 | |||
18 | This document should be considered the authoritative description of the |
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18 | This document should be considered the authoritative description of the | |
19 | IPython messaging protocol, and all developers are strongly encouraged to |
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19 | IPython messaging protocol, and all developers are strongly encouraged to | |
20 | keep it updated as the implementation evolves, so that we have a single |
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20 | keep it updated as the implementation evolves, so that we have a single | |
21 | common reference for all protocol details. |
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21 | common reference for all protocol details. | |
22 |
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22 | |||
23 | The basic design is explained in the following diagram: |
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23 | The basic design is explained in the following diagram: | |
24 |
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24 | |||
25 | .. image:: frontend-kernel.png |
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25 | .. image:: frontend-kernel.png | |
26 | :width: 450px |
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26 | :width: 450px | |
27 | :alt: IPython kernel/frontend messaging architecture. |
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27 | :alt: IPython kernel/frontend messaging architecture. | |
28 | :align: center |
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28 | :align: center | |
29 | :target: ../_images/frontend-kernel.png |
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29 | :target: ../_images/frontend-kernel.png | |
30 |
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30 | |||
31 | A single kernel can be simultaneously connected to one or more frontends. The |
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31 | A single kernel can be simultaneously connected to one or more frontends. The | |
32 | kernel has three sockets that serve the following functions: |
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32 | kernel has three sockets that serve the following functions: | |
33 |
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33 | |||
34 | 1. REQ: this socket is connected to a *single* frontend at a time, and it allows |
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34 | 1. REQ: this socket is connected to a *single* frontend at a time, and it allows | |
35 | the kernel to request input from a frontend when :func:`raw_input` is called. |
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35 | the kernel to request input from a frontend when :func:`raw_input` is called. | |
36 | The frontend holding the matching REP socket acts as a 'virtual keyboard' |
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36 | The frontend holding the matching REP socket acts as a 'virtual keyboard' | |
37 | for the kernel while this communication is happening (illustrated in the |
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37 | for the kernel while this communication is happening (illustrated in the | |
38 | figure by the black outline around the central keyboard). In practice, |
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38 | figure by the black outline around the central keyboard). In practice, | |
39 | frontends may display such kernel requests using a special input widget or |
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39 | frontends may display such kernel requests using a special input widget or | |
40 | otherwise indicating that the user is to type input for the kernel instead |
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40 | otherwise indicating that the user is to type input for the kernel instead | |
41 | of normal commands in the frontend. |
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41 | of normal commands in the frontend. | |
42 |
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42 | |||
43 | 2. XREP: this single sockets allows multiple incoming connections from |
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43 | 2. XREP: this single sockets allows multiple incoming connections from | |
44 | frontends, and this is the socket where requests for code execution, object |
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44 | frontends, and this is the socket where requests for code execution, object | |
45 | information, prompts, etc. are made to the kernel by any frontend. The |
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45 | information, prompts, etc. are made to the kernel by any frontend. The | |
46 | communication on this socket is a sequence of request/reply actions from |
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46 | communication on this socket is a sequence of request/reply actions from | |
47 | each frontend and the kernel. |
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47 | each frontend and the kernel. | |
48 |
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48 | |||
49 | 3. PUB: this socket is the 'broadcast channel' where the kernel publishes all |
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49 | 3. PUB: this socket is the 'broadcast channel' where the kernel publishes all | |
50 | side effects (stdout, stderr, etc.) as well as the requests coming from any |
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50 | side effects (stdout, stderr, etc.) as well as the requests coming from any | |
51 | client over the XREP socket and its own requests on the REP socket. There |
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51 | client over the XREP socket and its own requests on the REP socket. There | |
52 | are a number of actions in Python which generate side effects: :func:`print` |
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52 | are a number of actions in Python which generate side effects: :func:`print` | |
53 | writes to ``sys.stdout``, errors generate tracebacks, etc. Additionally, in |
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53 | writes to ``sys.stdout``, errors generate tracebacks, etc. Additionally, in | |
54 | a multi-client scenario, we want all frontends to be able to know what each |
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54 | a multi-client scenario, we want all frontends to be able to know what each | |
55 | other has sent to the kernel (this can be useful in collaborative scenarios, |
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55 | other has sent to the kernel (this can be useful in collaborative scenarios, | |
56 | for example). This socket allows both side effects and the information |
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56 | for example). This socket allows both side effects and the information | |
57 | about communications taking place with one client over the XREQ/XREP channel |
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57 | about communications taking place with one client over the XREQ/XREP channel | |
58 | to be made available to all clients in a uniform manner. |
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58 | to be made available to all clients in a uniform manner. | |
59 |
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59 | |||
60 | All messages are tagged with enough information (details below) for clients |
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60 | All messages are tagged with enough information (details below) for clients | |
61 | to know which messages come from their own interaction with the kernel and |
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61 | to know which messages come from their own interaction with the kernel and | |
62 | which ones are from other clients, so they can display each type |
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62 | which ones are from other clients, so they can display each type | |
63 | appropriately. |
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63 | appropriately. | |
64 |
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64 | |||
65 | The actual format of the messages allowed on each of these channels is |
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65 | The actual format of the messages allowed on each of these channels is | |
66 | specified below. Messages are dicts of dicts with string keys and values that |
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66 | specified below. Messages are dicts of dicts with string keys and values that | |
67 | are reasonably representable in JSON. Our current implementation uses JSON |
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67 | are reasonably representable in JSON. Our current implementation uses JSON | |
68 | explicitly as its message format, but this shouldn't be considered a permanent |
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68 | explicitly as its message format, but this shouldn't be considered a permanent | |
69 | feature. As we've discovered that JSON has non-trivial performance issues due |
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69 | feature. As we've discovered that JSON has non-trivial performance issues due | |
70 | to excessive copying, we may in the future move to a pure pickle-based raw |
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70 | to excessive copying, we may in the future move to a pure pickle-based raw | |
71 | message format. However, it should be possible to easily convert from the raw |
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71 | message format. However, it should be possible to easily convert from the raw | |
72 | objects to JSON, since we may have non-python clients (e.g. a web frontend). |
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72 | objects to JSON, since we may have non-python clients (e.g. a web frontend). | |
73 | As long as it's easy to make a JSON version of the objects that is a faithful |
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73 | As long as it's easy to make a JSON version of the objects that is a faithful | |
74 | representation of all the data, we can communicate with such clients. |
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74 | representation of all the data, we can communicate with such clients. | |
75 |
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75 | |||
76 | .. Note:: |
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76 | .. Note:: | |
77 |
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77 | |||
78 | Not all of these have yet been fully fleshed out, but the key ones are, see |
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78 | Not all of these have yet been fully fleshed out, but the key ones are, see | |
79 | kernel and frontend files for actual implementation details. |
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79 | kernel and frontend files for actual implementation details. | |
80 |
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80 | |||
81 |
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81 | |||
82 | Python functional API |
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82 | Python functional API | |
83 | ===================== |
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83 | ===================== | |
84 |
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84 | |||
85 | As messages are dicts, they map naturally to a ``func(**kw)`` call form. We |
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85 | As messages are dicts, they map naturally to a ``func(**kw)`` call form. We | |
86 | should develop, at a few key points, functional forms of all the requests that |
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86 | should develop, at a few key points, functional forms of all the requests that | |
87 | take arguments in this manner and automatically construct the necessary dict |
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87 | take arguments in this manner and automatically construct the necessary dict | |
88 | for sending. |
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88 | for sending. | |
89 |
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89 | |||
90 |
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90 | |||
91 | General Message Format |
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91 | General Message Format | |
92 | ====================== |
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92 | ====================== | |
93 |
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93 | |||
94 | All messages send or received by any IPython process should have the following |
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94 | All messages send or received by any IPython process should have the following | |
95 | generic structure:: |
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95 | generic structure:: | |
96 |
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96 | |||
97 | { |
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97 | { | |
98 | # The message header contains a pair of unique identifiers for the |
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98 | # The message header contains a pair of unique identifiers for the | |
99 | # originating session and the actual message id, in addition to the |
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99 | # originating session and the actual message id, in addition to the | |
100 | # username for the process that generated the message. This is useful in |
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100 | # username for the process that generated the message. This is useful in | |
101 | # collaborative settings where multiple users may be interacting with the |
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101 | # collaborative settings where multiple users may be interacting with the | |
102 | # same kernel simultaneously, so that frontends can label the various |
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102 | # same kernel simultaneously, so that frontends can label the various | |
103 | # messages in a meaningful way. |
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103 | # messages in a meaningful way. | |
104 | 'header' : { 'msg_id' : uuid, |
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104 | 'header' : { 'msg_id' : uuid, | |
105 | 'username' : str, |
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105 | 'username' : str, | |
106 | 'session' : uuid |
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106 | 'session' : uuid | |
107 | }, |
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107 | }, | |
108 |
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108 | |||
109 | # In a chain of messages, the header from the parent is copied so that |
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109 | # In a chain of messages, the header from the parent is copied so that | |
110 | # clients can track where messages come from. |
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110 | # clients can track where messages come from. | |
111 | 'parent_header' : dict, |
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111 | 'parent_header' : dict, | |
112 |
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112 | |||
113 | # All recognized message type strings are listed below. |
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113 | # All recognized message type strings are listed below. | |
114 | 'msg_type' : str, |
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114 | 'msg_type' : str, | |
115 |
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115 | |||
116 | # The actual content of the message must be a dict, whose structure |
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116 | # The actual content of the message must be a dict, whose structure | |
117 | # depends on the message type.x |
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117 | # depends on the message type.x | |
118 | 'content' : dict, |
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118 | 'content' : dict, | |
119 | } |
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119 | } | |
120 |
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120 | |||
121 | For each message type, the actual content will differ and all existing message |
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121 | For each message type, the actual content will differ and all existing message | |
122 | types are specified in what follows of this document. |
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122 | types are specified in what follows of this document. | |
123 |
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123 | |||
124 |
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124 | |||
125 | Messages on the XREP/XREQ socket |
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125 | Messages on the XREP/XREQ socket | |
126 | ================================ |
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126 | ================================ | |
127 |
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127 | |||
128 | .. _execute: |
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128 | .. _execute: | |
129 |
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129 | |||
130 | Execute |
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130 | Execute | |
131 | ------- |
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131 | ------- | |
132 |
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132 | |||
133 | The execution request contains a single string, but this may be a multiline |
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133 | The execution request contains a single string, but this may be a multiline | |
134 | string. The kernel is responsible for splitting this into possibly more than |
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134 | string. The kernel is responsible for splitting this into possibly more than | |
135 | one block and deciding whether to compile these in 'single' or 'exec' mode. |
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135 | one block and deciding whether to compile these in 'single' or 'exec' mode. | |
136 | We're still sorting out this policy. The current inputsplitter is capable of |
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136 | We're still sorting out this policy. The current inputsplitter is capable of | |
137 | splitting the input for blocks that can all be run as 'single', but in the long |
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137 | splitting the input for blocks that can all be run as 'single', but in the long | |
138 | run it may prove cleaner to only use 'single' mode for truly single-line |
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138 | run it may prove cleaner to only use 'single' mode for truly single-line | |
139 | inputs, and run all multiline input in 'exec' mode. This would preserve the |
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139 | inputs, and run all multiline input in 'exec' mode. This would preserve the | |
140 | natural behavior of single-line inputs while allowing long cells to behave more |
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140 | natural behavior of single-line inputs while allowing long cells to behave more | |
141 | likea a script. This design will be refined as we complete the implementation. |
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141 | likea a script. This design will be refined as we complete the implementation. | |
142 |
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142 | |||
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143 | .. Note:: | |||
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144 | ||||
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145 | What today we call 'prompt requests' will be encoded in the | |||
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146 | ``state_template`` field. | |||
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147 | ||||
143 | Message type: ``execute_request``:: |
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148 | Message type: ``execute_request``:: | |
144 |
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149 | |||
145 | content = { |
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150 | content = { | |
146 | # Source code to be executed by the kernel, one or more lines. |
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151 | # Source code to be executed by the kernel, one or more lines. | |
147 | 'code' : str, |
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152 | 'code' : str, | |
148 |
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153 | |||
149 | # A boolean flag which, if True, signals the kernel to execute this |
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154 | # A boolean flag which, if True, signals the kernel to execute this | |
150 | # code as quietly as possible. This means that the kernel will compile |
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155 | # code as quietly as possible. This means that the kernel will compile | |
151 |
# the code with 'exec' instead of 'single' (so |
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156 | # the code witIPython/core/tests/h 'exec' instead of 'single' (so | |
152 | # fire), and will *not*: |
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157 | # sys.displayhook will not fire), and will *not*: | |
153 | # - broadcast exceptions on the PUB socket |
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158 | # - broadcast exceptions on the PUB socket | |
154 | # - do any logging |
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159 | # - do any logging | |
155 | # - populate any history |
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160 | # - populate any history | |
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161 | # | |||
156 | # The default is False. |
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162 | # The default is False. | |
157 | 'silent' : bool, |
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163 | 'silent' : bool, | |
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164 | ||||
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165 | # An optional string to request arbitrary state information from the | |||
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166 | # kernel. This string is evaluated via the itpl module, and it can | |||
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167 | # therefore contain arbitrary code for execution. | |||
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168 | ||||
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169 | 'state_template' : str, | |||
158 | } |
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170 | } | |
159 |
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171 | |||
160 | Upon execution, the kernel *always* sends a reply, with a status code |
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172 | Execution semantics | |
161 | indicating what happened and additional data depending on the outcome. |
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173 | Upon execution of the ``code`` field, the kernel *always* sends a reply, | |
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174 | with a status code indicating what happened and additional data depending | |||
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175 | on the outcome. | |||
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176 | ||||
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177 | Any code in the ``state_template`` string is evaluated, but full exceptions | |||
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178 | that may occur are *not* propagated back. If any error occurs during the | |||
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179 | evaluation, the value of the string will simply be:: | |||
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180 | ||||
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181 | [ERROR in <contents of template>: ExceptionType - Exception message] | |||
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182 | ||||
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183 | The user can simply send the same code contained in the template for normal | |||
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184 | evaluation to see a regular traceback. | |||
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185 | ||||
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186 | Execution counter (old prompt number) | |||
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187 | The kernel has a single, monotonically increasing counter of all execution | |||
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188 | requests that are made with ``silent=False``. This counter is used to | |||
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189 | populate the ``In[n]``, ``Out[n]`` and ``_n`` variables, so clients will | |||
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190 | likely want to display it in some form to the user, which will typically | |||
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191 | (but not necessarily) be done in the prompts. The value of this counter | |||
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192 | will be returned as the ``execution_count`` field of all ``execute_reply``` | |||
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193 | messages. | |||
162 |
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194 | |||
163 | Message type: ``execute_reply``:: |
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195 | Message type: ``execute_reply``:: | |
164 |
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196 | |||
165 | content = { |
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197 | content = { | |
166 | # One of: 'ok' OR 'error' OR 'abort' |
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198 | # One of: 'ok' OR 'error' OR 'abort' | |
167 | 'status' : str, |
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199 | 'status' : str, | |
168 |
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200 | |||
169 | # This has the same structure as the output of a prompt request, but is |
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201 | # The global kernel counter that increases by one with each non-silent | |
170 | # for the client to set up the *next* prompt (with identical limitations |
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202 | # executed request. This will typically be used by clients to display | |
171 | # to a prompt request) |
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203 | # prompt numbers to the user. If the request was a silent one, this will | |
172 | 'next_prompt' : { |
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204 | # be the current value of the counter in the kernel. | |
173 | 'prompt_string' : str, |
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205 | 'execution_count' : int, | |
174 | 'prompt_number' : int, |
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206 | ||
175 | 'input_sep' : str |
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207 | # If the state_template was provided, this will contain the evaluated | |
176 | }, |
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208 | # form of the template. | |
177 |
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209 | 'state' : str, | ||
178 | # The prompt number of the actual execution for this code, which may be |
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179 | # different from the one used when the code was typed, which was the |
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180 | # 'next_prompt' field of the *previous* request. They will differ in the |
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181 | # case where there is more than one client talking simultaneously to a |
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182 | # kernel, since the numbers can go out of sync. GUI clients can use this |
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183 | # to correct the previously written number in-place, terminal ones may |
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184 | # re-print a corrected one if desired. |
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185 | 'prompt_number' : int, |
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186 | } |
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210 | } | |
187 |
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211 | |||
188 | When status is 'ok', the following extra fields are present:: |
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212 | When status is 'ok', the following extra fields are present:: | |
189 |
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213 | |||
190 | { |
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214 | { | |
191 |
# The kernel will often transform the input provided to it. |
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215 | # The kernel will often transform the input provided to it. If the | |
192 | # contains the transformed code, which is what was actually executed. |
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216 | # '---->' transform had been applied, this is filled, otherwise it's the | |
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217 | # empty string. So transformations like magics don't appear here, only | |||
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218 | # autocall ones. | |||
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219 | ||||
193 | 'transformed_code' : str, |
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220 | 'transformed_code' : str, | |
194 |
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221 | |||
195 | # The execution payload is a dict with string keys that may have been |
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222 | # The execution payload is a dict with string keys that may have been | |
196 | # produced by the code being executed. It is retrieved by the kernel at |
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223 | # produced by the code being executed. It is retrieved by the kernel at | |
197 | # the end of the execution and sent back to the front end, which can take |
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224 | # the end of the execution and sent back to the front end, which can take | |
198 | # action on it as needed. See main text for further details. |
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225 | # action on it as needed. See main text for further details. | |
199 | 'payload' : dict, |
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226 | 'payload' : dict, | |
200 | } |
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227 | } | |
201 |
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228 | |||
202 | .. admonition:: Execution payloads |
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229 | .. admonition:: Execution payloads | |
203 |
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230 | |||
204 | The notion of an 'execution payload' is different from a return value of a |
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231 | The notion of an 'execution payload' is different from a return value of a | |
205 | given set of code, which normally is just displayed on the pyout stream |
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232 | given set of code, which normally is just displayed on the pyout stream | |
206 | through the PUB socket. The idea of a payload is to allow special types of |
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233 | through the PUB socket. The idea of a payload is to allow special types of | |
207 | code, typically magics, to populate a data container in the IPython kernel |
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234 | code, typically magics, to populate a data container in the IPython kernel | |
208 | that will be shipped back to the caller via this channel. The kernel will |
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235 | that will be shipped back to the caller via this channel. The kernel will | |
209 | have an API for this, probably something along the lines of:: |
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236 | have an API for this, probably something along the lines of:: | |
210 |
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237 | |||
211 | ip.exec_payload_add(key, value) |
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238 | ip.exec_payload_add(key, value) | |
212 |
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239 | |||
213 | though this API is still in the design stages. The data returned in this |
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240 | though this API is still in the design stages. The data returned in this | |
214 | payload will allow frontends to present special views of what just happened. |
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241 | payload will allow frontends to present special views of what just happened. | |
215 |
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242 | |||
216 |
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243 | |||
217 | When status is 'error', the following extra fields are present:: |
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244 | When status is 'error', the following extra fields are present:: | |
218 |
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245 | |||
219 | { |
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246 | { | |
220 | 'exc_name' : str, # Exception name, as a string |
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247 | 'exc_name' : str, # Exception name, as a string | |
221 | 'exc_value' : str, # Exception value, as a string |
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248 | 'exc_value' : str, # Exception value, as a string | |
222 |
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249 | |||
223 | # The traceback will contain a list of frames, represented each as a |
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250 | # The traceback will contain a list of frames, represented each as a | |
224 | # string. For now we'll stick to the existing design of ultraTB, which |
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251 | # string. For now we'll stick to the existing design of ultraTB, which | |
225 | # controls exception level of detail statefully. But eventually we'll |
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252 | # controls exception level of detail statefully. But eventually we'll | |
226 | # want to grow into a model where more information is collected and |
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253 | # want to grow into a model where more information is collected and | |
227 | # packed into the traceback object, with clients deciding how little or |
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254 | # packed into the traceback object, with clients deciding how little or | |
228 | # how much of it to unpack. But for now, let's start with a simple list |
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255 | # how much of it to unpack. But for now, let's start with a simple list | |
229 | # of strings, since that requires only minimal changes to ultratb as |
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256 | # of strings, since that requires only minimal changes to ultratb as | |
230 | # written. |
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257 | # written. | |
231 | 'traceback' : list, |
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258 | 'traceback' : list, | |
232 | } |
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259 | } | |
233 |
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260 | |||
234 |
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261 | |||
235 | When status is 'abort', there are for now no additional data fields. This |
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262 | When status is 'abort', there are for now no additional data fields. This | |
236 | happens when the kernel was interrupted by a signal. |
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263 | happens when the kernel was interrupted by a signal. | |
237 |
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264 | |||
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265 | Kernel attribute access | |||
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266 | ----------------------- | |||
238 |
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267 | |||
239 | Prompt |
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268 | While this protocol does not specify full RPC access to arbitrary methods of | |
240 | ------ |
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269 | the kernel object, the kernel does allow read (and in some cases write) access | |
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270 | to certain attributes. | |||
241 |
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271 | |||
242 | A simple request for a current prompt string. |
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272 | The policy for which attributes can be read is: any attribute of the kernel, or | |
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273 | its sub-objects, that belongs to a :class:`Configurable` object and has been | |||
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274 | declared at the class-level with Traits validation, is in principle accessible | |||
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275 | as long as its name does not begin with a leading underscore. The attribute | |||
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276 | itself will have metadata indicating whether it allows remote read and/or write | |||
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277 | access. The message spec follows for attribute read and write requests. | |||
243 |
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278 | |||
244 |
Message type: `` |
|
279 | Message type: ``getattr_request``:: | |
245 |
|
280 | |||
246 |
content = { |
|
281 | content = { | |
|
282 | # The (possibly dotted) name of the attribute | |||
|
283 | 'name' : str | |||
|
284 | } | |||
247 |
|
285 | |||
248 | In the reply, the prompt string comes back with the prompt number placeholder |
|
286 | When a ``getattr_request`` fails, there are two possible error types: | |
249 | *unevaluated*. The message format is: |
|
287 | ||
250 |
|
288 | - AttributeError: this type of error was raised when trying to access the | ||
251 | Message type: ``prompt_reply``:: |
|
289 | given name by the kernel itself. This means that the attribute likely | |
|
290 | doesn't exist. | |||
|
291 | ||||
|
292 | - AccessError: the attribute exists but its value is not readable remotely. | |||
|
293 | ||||
|
294 | ||||
|
295 | Message type: ``getattr_reply``:: | |||
|
296 | ||||
|
297 | content = { | |||
|
298 | # One of ['ok', 'AttributeError', 'AccessError']. | |||
|
299 | 'status' : str | |||
|
300 | # If status is 'ok', a JSON object. | |||
|
301 | 'value' : object | |||
|
302 | } | |||
|
303 | ||||
|
304 | Message type: ``setattr_request``:: | |||
252 |
|
305 | |||
253 | content = { |
|
306 | content = { | |
254 | 'prompt_string' : str, |
|
307 | # The (possibly dotted) name of the attribute | |
255 | 'prompt_number' : int, |
|
308 | 'name' : str | |
256 | 'input_sep' : str |
|
309 | ||
|
310 | # A JSON-encoded object, that will be validated by the Traits | |||
|
311 | # information in the kernel | |||
|
312 | 'value' : object | |||
257 | } |
|
313 | } | |
258 |
|
314 | |||
259 | Clients can produce a prompt with ``prompt_string.format(prompt_number)``, but |
|
315 | When a ``setattr_request`` fails, there are also two possible error types with | |
260 | they should be aware that the actual prompt number for that input could change |
|
316 | similar meanings as those of the ``getattr_request`` case, but for writing. | |
261 | later, in the case where multiple clients are interacting with a single |
|
317 | ||
262 | kernel. |
|
318 | Message type: ``setattr_reply``:: | |
|
319 | ||||
|
320 | content = { | |||
|
321 | # One of ['ok', 'AttributeError', 'AccessError']. | |||
|
322 | 'status' : str | |||
|
323 | } | |||
263 |
|
324 | |||
264 |
|
325 | |||
265 | Object information |
|
326 | Object information | |
266 | ------------------ |
|
327 | ------------------ | |
267 |
|
328 | |||
268 | One of IPython's most used capabilities is the introspection of Python objects |
|
329 | One of IPython's most used capabilities is the introspection of Python objects | |
269 | in the user's namespace, typically invoked via the ``?`` and ``??`` characters |
|
330 | in the user's namespace, typically invoked via the ``?`` and ``??`` characters | |
270 | (which in reality are shorthands for the ``%pinfo`` magic). This is used often |
|
331 | (which in reality are shorthands for the ``%pinfo`` magic). This is used often | |
271 | enough that it warrants an explicit message type, especially because frontends |
|
332 | enough that it warrants an explicit message type, especially because frontends | |
272 | may want to get object information in response to user keystrokes (like Tab or |
|
333 | may want to get object information in response to user keystrokes (like Tab or | |
273 | F1) besides from the user explicitly typing code like ``x??``. |
|
334 | F1) besides from the user explicitly typing code like ``x??``. | |
274 |
|
335 | |||
275 | Message type: ``object_info_request``:: |
|
336 | Message type: ``object_info_request``:: | |
276 |
|
337 | |||
277 | content = { |
|
338 | content = { | |
278 | # The (possibly dotted) name of the object to be searched in all |
|
339 | # The (possibly dotted) name of the object to be searched in all | |
279 |
|
|
340 | # relevant namespaces | |
280 | 'name' : str, |
|
341 | 'name' : str, | |
281 |
|
342 | |||
282 | # The level of detail desired. The default (0) is equivalent to typing |
|
343 | # The level of detail desired. The default (0) is equivalent to typing | |
283 |
|
|
344 | # 'x?' at the prompt, 1 is equivalent to 'x??'. | |
284 |
|
|
345 | 'detail_level' : int, | |
285 | } |
|
346 | } | |
286 |
|
347 | |||
287 | The returned information will be a dictionary with keys very similar to the |
|
348 | The returned information will be a dictionary with keys very similar to the | |
288 | field names that IPython prints at the terminal. |
|
349 | field names that IPython prints at the terminal. | |
289 |
|
350 | |||
290 | Message type: ``object_info_reply``:: |
|
351 | Message type: ``object_info_reply``:: | |
291 |
|
352 | |||
292 | content = { |
|
353 | content = { | |
293 | # Flags for magics and system aliases |
|
354 | # Flags for magics and system aliases | |
294 | 'ismagic' : bool, |
|
355 | 'ismagic' : bool, | |
295 | 'isalias' : bool, |
|
356 | 'isalias' : bool, | |
296 |
|
357 | |||
297 | # The name of the namespace where the object was found ('builtin', |
|
358 | # The name of the namespace where the object was found ('builtin', | |
298 | # 'magics', 'alias', 'interactive', etc.) |
|
359 | # 'magics', 'alias', 'interactive', etc.) | |
299 | 'namespace' : str, |
|
360 | 'namespace' : str, | |
300 |
|
361 | |||
301 | # The type name will be type.__name__ for normal Python objects, but it |
|
362 | # The type name will be type.__name__ for normal Python objects, but it | |
302 | # can also be a string like 'Magic function' or 'System alias' |
|
363 | # can also be a string like 'Magic function' or 'System alias' | |
303 | 'type_name' : str, |
|
364 | 'type_name' : str, | |
304 |
|
365 | |||
305 | 'string_form' : str, |
|
366 | 'string_form' : str, | |
306 |
|
367 | |||
307 | # For objects with a __class__ attribute this will be set |
|
368 | # For objects with a __class__ attribute this will be set | |
308 | 'base_class' : str, |
|
369 | 'base_class' : str, | |
309 |
|
370 | |||
310 | # For objects with a __len__ attribute this will be set |
|
371 | # For objects with a __len__ attribute this will be set | |
311 | 'length' : int, |
|
372 | 'length' : int, | |
312 |
|
373 | |||
313 | # If the object is a function, class or method whose file we can find, |
|
374 | # If the object is a function, class or method whose file we can find, | |
314 | # we give its full path |
|
375 | # we give its full path | |
315 | 'file' : str, |
|
376 | 'file' : str, | |
316 |
|
377 | |||
317 | # For pure Python callable objects, we can reconstruct the object |
|
378 | # For pure Python callable objects, we can reconstruct the object | |
318 | # definition line which provides its call signature |
|
379 | # definition line which provides its call signature. For convenience this | |
|
380 | # is returned as a single 'definition' field, but below the raw parts that | |||
|
381 | # compose it are also returned as the argspec field. | |||
319 | 'definition' : str, |
|
382 | 'definition' : str, | |
320 |
|
383 | |||
|
384 | # The individual parts that together form the definition string. Clients | |||
|
385 | # with rich display capabilities may use this to provide a richer and more | |||
|
386 | # precise representation of the definition line (e.g. by highlighting | |||
|
387 | # arguments based on the user's cursor position). For non-callable | |||
|
388 | # objects, this field is empty. | |||
|
389 | 'argspec' : { # The names of all the arguments | |||
|
390 | args : list, | |||
|
391 | # The name of the varargs (*args), if any | |||
|
392 | varargs : str, | |||
|
393 | # The name of the varkw (**kw), if any | |||
|
394 | varkw : str | |||
|
395 | # The values (as strings) of all default arguments. Note | |||
|
396 | # that these must be matched *in reverse* with the 'args' | |||
|
397 | # list above, since the first positional args have no default | |||
|
398 | # value at all. | |||
|
399 | func_defaults : list | |||
|
400 | } | |||
|
401 | ||||
321 | # For instances, provide the constructor signature (the definition of |
|
402 | # For instances, provide the constructor signature (the definition of | |
322 | # the __init__ method): |
|
403 | # the __init__ method): | |
323 | 'init_definition' : str, |
|
404 | 'init_definition' : str, | |
324 |
|
405 | |||
325 | # Docstrings: for any object (function, method, module, package) with a |
|
406 | # Docstrings: for any object (function, method, module, package) with a | |
326 | # docstring, we show it. But in addition, we may provide additional |
|
407 | # docstring, we show it. But in addition, we may provide additional | |
327 | # docstrings. For example, for instances we will show the constructor |
|
408 | # docstrings. For example, for instances we will show the constructor | |
328 | # and class docstrings as well, if available. |
|
409 | # and class docstrings as well, if available. | |
329 | 'docstring' : str, |
|
410 | 'docstring' : str, | |
330 |
|
411 | |||
331 | # For instances, provide the constructor and class docstrings |
|
412 | # For instances, provide the constructor and class docstrings | |
332 | 'init_docstring' : str, |
|
413 | 'init_docstring' : str, | |
333 | 'class_docstring' : str, |
|
414 | 'class_docstring' : str, | |
334 |
|
415 | |||
335 | # If detail_level was 1, we also try to find the source code that |
|
416 | # If detail_level was 1, we also try to find the source code that | |
336 | # defines the object, if possible. The string 'None' will indicate |
|
417 | # defines the object, if possible. The string 'None' will indicate | |
337 | # that no source was found. |
|
418 | # that no source was found. | |
338 | 'source' : str, |
|
419 | 'source' : str, | |
339 | } |
|
420 | } | |
340 |
|
421 | |||
341 |
|
422 | |||
342 | Complete |
|
423 | Complete | |
343 | -------- |
|
424 | -------- | |
344 |
|
425 | |||
345 | Message type: ``complete_request``:: |
|
426 | Message type: ``complete_request``:: | |
346 |
|
427 | |||
347 | content = { |
|
428 | content = { | |
348 | # The text to be completed, such as 'a.is' |
|
429 | # The text to be completed, such as 'a.is' | |
349 | 'text' : str, |
|
430 | 'text' : str, | |
350 |
|
431 | |||
351 | # The full line, such as 'print a.is'. This allows completers to |
|
432 | # The full line, such as 'print a.is'. This allows completers to | |
352 | # make decisions that may require information about more than just the |
|
433 | # make decisions that may require information about more than just the | |
353 | # current word. |
|
434 | # current word. | |
354 | 'line' : str, |
|
435 | 'line' : str, | |
355 |
|
436 | |||
356 | # The entire block of text where the line is. This may be useful in the |
|
437 | # The entire block of text where the line is. This may be useful in the | |
357 | # case of multiline completions where more context may be needed. Note: if |
|
438 | # case of multiline completions where more context may be needed. Note: if | |
358 | # in practice this field proves unnecessary, remove it to lighten the |
|
439 | # in practice this field proves unnecessary, remove it to lighten the | |
359 | # messages. |
|
440 | # messages. | |
360 |
|
441 | |||
361 | 'block' : str, |
|
442 | 'block' : str, | |
362 |
|
443 | |||
363 | # The position of the cursor where the user hit 'TAB' on the line. |
|
444 | # The position of the cursor where the user hit 'TAB' on the line. | |
364 | 'cursor_pos' : int, |
|
445 | 'cursor_pos' : int, | |
365 | } |
|
446 | } | |
366 |
|
447 | |||
367 | Message type: ``complete_reply``:: |
|
448 | Message type: ``complete_reply``:: | |
368 |
|
449 | |||
369 | content = { |
|
450 | content = { | |
370 | # The list of all matches to the completion request, such as |
|
451 | # The list of all matches to the completion request, such as | |
371 | # ['a.isalnum', 'a.isalpha'] for the above example. |
|
452 | # ['a.isalnum', 'a.isalpha'] for the above example. | |
372 | 'matches' : list |
|
453 | 'matches' : list | |
373 | } |
|
454 | } | |
374 |
|
455 | |||
375 |
|
456 | |||
376 | History |
|
457 | History | |
377 | ------- |
|
458 | ------- | |
378 |
|
459 | |||
379 | For clients to explicitly request history from a kernel. The kernel has all |
|
460 | For clients to explicitly request history from a kernel. The kernel has all | |
380 | the actual execution history stored in a single location, so clients can |
|
461 | the actual execution history stored in a single location, so clients can | |
381 | request it from the kernel when needed. |
|
462 | request it from the kernel when needed. | |
382 |
|
463 | |||
383 | Message type: ``history_request``:: |
|
464 | Message type: ``history_request``:: | |
384 |
|
465 | |||
385 | content = { |
|
466 | content = { | |
386 |
|
467 | |||
387 | # If True, also return output history in the resulting dict. |
|
468 | # If True, also return output history in the resulting dict. | |
388 | 'output' : bool, |
|
469 | 'output' : bool, | |
389 |
|
470 | |||
390 | # If True, return the raw input history, else the transformed input. |
|
471 | # If True, return the raw input history, else the transformed input. | |
391 | 'raw' : bool, |
|
472 | 'raw' : bool, | |
392 |
|
473 | |||
393 | # This parameter can be one of: A number, a pair of numbers, None |
|
474 | # This parameter can be one of: A number, a pair of numbers, None | |
394 | # If not given, last 40 are returned. |
|
475 | # If not given, last 40 are returned. | |
395 | # - number n: return the last n entries. |
|
476 | # - number n: return the last n entries. | |
396 | # - pair n1, n2: return entries in the range(n1, n2). |
|
477 | # - pair n1, n2: return entries in the range(n1, n2). | |
397 | # - None: return all history |
|
478 | # - None: return all history | |
398 | 'index' : n or (n1, n2) or None, |
|
479 | 'index' : n or (n1, n2) or None, | |
399 | } |
|
480 | } | |
400 |
|
481 | |||
401 | Message type: ``history_reply``:: |
|
482 | Message type: ``history_reply``:: | |
402 |
|
483 | |||
403 | content = { |
|
484 | content = { | |
404 | # A dict with prompt numbers as keys and either (input, output) or input |
|
485 | # A dict with prompt numbers as keys and either (input, output) or input | |
405 | # as the value depending on whether output was True or False, |
|
486 | # as the value depending on whether output was True or False, | |
406 | # respectively. |
|
487 | # respectively. | |
407 | 'history' : dict, |
|
488 | 'history' : dict, | |
408 | } |
|
489 | } | |
409 | Messages on the PUB/SUB socket |
|
490 | Messages on the PUB/SUB socket | |
410 | ============================== |
|
491 | ============================== | |
411 |
|
492 | |||
412 | Streams (stdout, stderr, etc) |
|
493 | Streams (stdout, stderr, etc) | |
413 | ------------------------------ |
|
494 | ------------------------------ | |
414 |
|
495 | |||
415 | Message type: ``stream``:: |
|
496 | Message type: ``stream``:: | |
416 |
|
497 | |||
417 | content = { |
|
498 | content = { | |
418 | # The name of the stream is one of 'stdin', 'stdout', 'stderr' |
|
499 | # The name of the stream is one of 'stdin', 'stdout', 'stderr' | |
419 | 'name' : str, |
|
500 | 'name' : str, | |
420 |
|
501 | |||
421 | # The data is an arbitrary string to be written to that stream |
|
502 | # The data is an arbitrary string to be written to that stream | |
422 | 'data' : str, |
|
503 | 'data' : str, | |
423 | } |
|
504 | } | |
424 |
|
505 | |||
425 | When a kernel receives a raw_input call, it should also broadcast it on the pub |
|
506 | When a kernel receives a raw_input call, it should also broadcast it on the pub | |
426 | socket with the names 'stdin' and 'stdin_reply'. This will allow other clients |
|
507 | socket with the names 'stdin' and 'stdin_reply'. This will allow other clients | |
427 | to monitor/display kernel interactions and possibly replay them to their user |
|
508 | to monitor/display kernel interactions and possibly replay them to their user | |
428 | or otherwise expose them. |
|
509 | or otherwise expose them. | |
429 |
|
510 | |||
430 | Python inputs |
|
511 | Python inputs | |
431 | ------------- |
|
512 | ------------- | |
432 |
|
513 | |||
433 | These messages are the re-broadcast of the ``execute_request``. |
|
514 | These messages are the re-broadcast of the ``execute_request``. | |
434 |
|
515 | |||
435 | Message type: ``pyin``:: |
|
516 | Message type: ``pyin``:: | |
436 |
|
517 | |||
437 | content = { |
|
518 | content = { | |
438 | # Source code to be executed, one or more lines |
|
519 | # Source code to be executed, one or more lines | |
439 | 'code' : str |
|
520 | 'code' : str | |
440 | } |
|
521 | } | |
441 |
|
522 | |||
442 | Python outputs |
|
523 | Python outputs | |
443 | -------------- |
|
524 | -------------- | |
444 |
|
525 | |||
445 | When Python produces output from code that has been compiled in with the |
|
526 | When Python produces output from code that has been compiled in with the | |
446 | 'single' flag to :func:`compile`, any expression that produces a value (such as |
|
527 | 'single' flag to :func:`compile`, any expression that produces a value (such as | |
447 | ``1+1``) is passed to ``sys.displayhook``, which is a callable that can do with |
|
528 | ``1+1``) is passed to ``sys.displayhook``, which is a callable that can do with | |
448 | this value whatever it wants. The default behavior of ``sys.displayhook`` in |
|
529 | this value whatever it wants. The default behavior of ``sys.displayhook`` in | |
449 | the Python interactive prompt is to print to ``sys.stdout`` the :func:`repr` of |
|
530 | the Python interactive prompt is to print to ``sys.stdout`` the :func:`repr` of | |
450 | the value as long as it is not ``None`` (which isn't printed at all). In our |
|
531 | the value as long as it is not ``None`` (which isn't printed at all). In our | |
451 | case, the kernel instantiates as ``sys.displayhook`` an object which has |
|
532 | case, the kernel instantiates as ``sys.displayhook`` an object which has | |
452 | similar behavior, but which instead of printing to stdout, broadcasts these |
|
533 | similar behavior, but which instead of printing to stdout, broadcasts these | |
453 | values as ``pyout`` messages for clients to display appropriately. |
|
534 | values as ``pyout`` messages for clients to display appropriately. | |
454 |
|
535 | |||
455 | Message type: ``pyout``:: |
|
536 | Message type: ``pyout``:: | |
456 |
|
537 | |||
457 | content = { |
|
538 | content = { | |
458 | # The data is typically the repr() of the object. |
|
539 | # The data is typically the repr() of the object. | |
459 | 'data' : str, |
|
540 | 'data' : str, | |
460 |
|
541 | |||
461 | # The prompt number for this execution is also provided so that clients |
|
542 | # The prompt number for this execution is also provided so that clients | |
462 | # can display it, since IPython automatically creates variables called |
|
543 | # can display it, since IPython automatically creates variables called | |
463 | # _N (for prompt N). |
|
544 | # _N (for prompt N). | |
464 | 'prompt_number' : int, |
|
545 | 'prompt_number' : int, | |
465 | } |
|
546 | } | |
466 |
|
547 | |||
467 | Python errors |
|
548 | Python errors | |
468 | ------------- |
|
549 | ------------- | |
469 |
|
550 | |||
470 | When an error occurs during code execution |
|
551 | When an error occurs during code execution | |
471 |
|
552 | |||
472 | Message type: ``pyerr``:: |
|
553 | Message type: ``pyerr``:: | |
473 |
|
554 | |||
474 | content = { |
|
555 | content = { | |
475 | # Similar content to the execute_reply messages for the 'error' case, |
|
556 | # Similar content to the execute_reply messages for the 'error' case, | |
476 | # except the 'status' field is omitted. |
|
557 | # except the 'status' field is omitted. | |
477 | } |
|
558 | } | |
478 |
|
559 | |||
479 | Kernel crashes |
|
560 | Kernel crashes | |
480 | -------------- |
|
561 | -------------- | |
481 |
|
562 | |||
482 | When the kernel has an unexpected exception, caught by the last-resort |
|
563 | When the kernel has an unexpected exception, caught by the last-resort | |
483 | sys.excepthook, we should broadcast the crash handler's output before exiting. |
|
564 | sys.excepthook, we should broadcast the crash handler's output before exiting. | |
484 | This will allow clients to notice that a kernel died, inform the user and |
|
565 | This will allow clients to notice that a kernel died, inform the user and | |
485 | propose further actions. |
|
566 | propose further actions. | |
486 |
|
567 | |||
487 | Message type: ``crash``:: |
|
568 | Message type: ``crash``:: | |
488 |
|
569 | |||
489 | content = { |
|
570 | content = { | |
490 | # Similarly to the 'error' case for execute_reply messages, this will |
|
571 | # Similarly to the 'error' case for execute_reply messages, this will | |
491 | # contain exc_name, exc_type and traceback fields. |
|
572 | # contain exc_name, exc_type and traceback fields. | |
492 |
|
573 | |||
493 | # An additional field with supplementary information such as where to |
|
574 | # An additional field with supplementary information such as where to | |
494 | # send the crash message |
|
575 | # send the crash message | |
495 | 'info' : str, |
|
576 | 'info' : str, | |
496 | } |
|
577 | } | |
497 |
|
578 | |||
498 |
|
579 | |||
499 | Future ideas |
|
580 | Future ideas | |
500 | ------------ |
|
581 | ------------ | |
501 |
|
582 | |||
502 | Other potential message types, currently unimplemented, listed below as ideas. |
|
583 | Other potential message types, currently unimplemented, listed below as ideas. | |
503 |
|
584 | |||
504 | Message type: ``file``:: |
|
585 | Message type: ``file``:: | |
505 |
|
586 | |||
506 | content = { |
|
587 | content = { | |
507 | 'path' : 'cool.jpg', |
|
588 | 'path' : 'cool.jpg', | |
508 | 'mimetype' : str, |
|
589 | 'mimetype' : str, | |
509 | 'data' : str, |
|
590 | 'data' : str, | |
510 | } |
|
591 | } | |
511 |
|
592 | |||
512 |
|
593 | |||
513 | Messages on the REQ/REP socket |
|
594 | Messages on the REQ/REP socket | |
514 | ============================== |
|
595 | ============================== | |
515 |
|
596 | |||
516 | This is a socket that goes in the opposite direction: from the kernel to a |
|
597 | This is a socket that goes in the opposite direction: from the kernel to a | |
517 | *single* frontend, and its purpose is to allow ``raw_input`` and similar |
|
598 | *single* frontend, and its purpose is to allow ``raw_input`` and similar | |
518 | operations that read from ``sys.stdin`` on the kernel to be fulfilled by the |
|
599 | operations that read from ``sys.stdin`` on the kernel to be fulfilled by the | |
519 | client. For now we will keep these messages as simple as possible, since they |
|
600 | client. For now we will keep these messages as simple as possible, since they | |
520 | basically only mean to convey the ``raw_input(prompt)`` call. |
|
601 | basically only mean to convey the ``raw_input(prompt)`` call. | |
521 |
|
602 | |||
522 | Message type: ``input_request``:: |
|
603 | Message type: ``input_request``:: | |
523 |
|
604 | |||
524 | content = { 'prompt' : str } |
|
605 | content = { 'prompt' : str } | |
525 |
|
606 | |||
526 | Message type: ``input_reply``:: |
|
607 | Message type: ``input_reply``:: | |
527 |
|
608 | |||
528 | content = { 'value' : str } |
|
609 | content = { 'value' : str } | |
529 |
|
610 | |||
530 | .. Note:: |
|
611 | .. Note:: | |
531 |
|
612 | |||
532 | We do not explicitly try to forward the raw ``sys.stdin`` object, because in |
|
613 | We do not explicitly try to forward the raw ``sys.stdin`` object, because in | |
533 | practice the kernel should behave like an interactive program. When a |
|
614 | practice the kernel should behave like an interactive program. When a | |
534 | program is opened on the console, the keyboard effectively takes over the |
|
615 | program is opened on the console, the keyboard effectively takes over the | |
535 | ``stdin`` file descriptor, and it can't be used for raw reading anymore. |
|
616 | ``stdin`` file descriptor, and it can't be used for raw reading anymore. | |
536 | Since the IPython kernel effectively behaves like a console program (albeit |
|
617 | Since the IPython kernel effectively behaves like a console program (albeit | |
537 | one whose "keyboard" is actually living in a separate process and |
|
618 | one whose "keyboard" is actually living in a separate process and | |
538 | transported over the zmq connection), raw ``stdin`` isn't expected to be |
|
619 | transported over the zmq connection), raw ``stdin`` isn't expected to be | |
539 | available. |
|
620 | available. | |
540 |
|
621 | |||
541 |
|
622 | |||
542 | Heartbeat for kernels |
|
623 | Heartbeat for kernels | |
543 | ===================== |
|
624 | ===================== | |
544 |
|
625 | |||
545 | Initially we had considered using messages like those above over ZMQ for a |
|
626 | Initially we had considered using messages like those above over ZMQ for a | |
546 | kernel 'heartbeat' (a way to detect quickly and reliably whether a kernel is |
|
627 | kernel 'heartbeat' (a way to detect quickly and reliably whether a kernel is | |
547 | alive at all, even if it may be busy executing user code). But this has the |
|
628 | alive at all, even if it may be busy executing user code). But this has the | |
548 | problem that if the kernel is locked inside extension code, it wouldn't execute |
|
629 | problem that if the kernel is locked inside extension code, it wouldn't execute | |
549 | the python heartbeat code. But it turns out that we can implement a basic |
|
630 | the python heartbeat code. But it turns out that we can implement a basic | |
550 | heartbeat with pure ZMQ, without using any Python messaging at all. |
|
631 | heartbeat with pure ZMQ, without using any Python messaging at all. | |
551 |
|
632 | |||
552 | The monitor sends out a single zmq message (right now, it is a str of the |
|
633 | The monitor sends out a single zmq message (right now, it is a str of the | |
553 | monitor's lifetime in seconds), and gets the same message right back, prefixed |
|
634 | monitor's lifetime in seconds), and gets the same message right back, prefixed | |
554 | with the zmq identity of the XREQ socket in the heartbeat process. This can be |
|
635 | with the zmq identity of the XREQ socket in the heartbeat process. This can be | |
555 | a uuid, or even a full message, but there doesn't seem to be a need for packing |
|
636 | a uuid, or even a full message, but there doesn't seem to be a need for packing | |
556 | up a message when the sender and receiver are the exact same Python object. |
|
637 | up a message when the sender and receiver are the exact same Python object. | |
557 |
|
638 | |||
558 | The model is this:: |
|
639 | The model is this:: | |
559 |
|
640 | |||
560 | monitor.send(str(self.lifetime)) # '1.2345678910' |
|
641 | monitor.send(str(self.lifetime)) # '1.2345678910' | |
561 |
|
642 | |||
562 | and the monitor receives some number of messages of the form:: |
|
643 | and the monitor receives some number of messages of the form:: | |
563 |
|
644 | |||
564 | ['uuid-abcd-dead-beef', '1.2345678910'] |
|
645 | ['uuid-abcd-dead-beef', '1.2345678910'] | |
565 |
|
646 | |||
566 | where the first part is the zmq.IDENTITY of the heart's XREQ on the engine, and |
|
647 | where the first part is the zmq.IDENTITY of the heart's XREQ on the engine, and | |
567 | the rest is the message sent by the monitor. No Python code ever has any |
|
648 | the rest is the message sent by the monitor. No Python code ever has any | |
568 | access to the message between the monitor's send, and the monitor's recv. |
|
649 | access to the message between the monitor's send, and the monitor's recv. | |
569 |
|
650 | |||
570 |
|
651 | |||
571 | ToDo |
|
652 | ToDo | |
572 | ==== |
|
653 | ==== | |
573 |
|
654 | |||
574 | Missing things include: |
|
655 | Missing things include: | |
575 |
|
656 | |||
576 | * Important: finish thinking through the payload concept and API. |
|
657 | * Important: finish thinking through the payload concept and API. | |
577 |
|
658 | |||
578 | * Important: ensure that we have a good solution for magics like %edit. It's |
|
659 | * Important: ensure that we have a good solution for magics like %edit. It's | |
579 | likely that with the payload concept we can build a full solution, but not |
|
660 | likely that with the payload concept we can build a full solution, but not | |
580 | 100% clear yet. |
|
661 | 100% clear yet. | |
581 |
|
662 | |||
582 | * Finishing the details of the heartbeat protocol. |
|
663 | * Finishing the details of the heartbeat protocol. | |
583 |
|
664 | |||
584 | * Signal handling: specify what kind of information kernel should broadcast (or |
|
665 | * Signal handling: specify what kind of information kernel should broadcast (or | |
585 | not) when it receives signals. |
|
666 | not) when it receives signals. | |
586 |
|
667 | |||
587 | .. include:: ../links.rst |
|
668 | .. include:: ../links.rst |
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