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sqlitedb.py
399 lines | 13.3 KiB | text/x-python | PythonLexer
"""A TaskRecord backend using sqlite3
Authors:
* Min RK
"""
#-----------------------------------------------------------------------------
# Copyright (C) 2011 The IPython Development Team
#
# Distributed under the terms of the BSD License. The full license is in
# the file COPYING, distributed as part of this software.
#-----------------------------------------------------------------------------
import json
import os
import cPickle as pickle
from datetime import datetime
import sqlite3
from zmq.eventloop import ioloop
from IPython.utils.traitlets import Unicode, Instance, List, Dict
from .dictdb import BaseDB
from IPython.utils.jsonutil import date_default, extract_dates, squash_dates
#-----------------------------------------------------------------------------
# SQLite operators, adapters, and converters
#-----------------------------------------------------------------------------
try:
buffer
except NameError:
# py3k
buffer = memoryview
operators = {
'$lt' : "<",
'$gt' : ">",
# null is handled weird with ==,!=
'$eq' : "=",
'$ne' : "!=",
'$lte': "<=",
'$gte': ">=",
'$in' : ('=', ' OR '),
'$nin': ('!=', ' AND '),
# '$all': None,
# '$mod': None,
# '$exists' : None
}
null_operators = {
'=' : "IS NULL",
'!=' : "IS NOT NULL",
}
def _adapt_dict(d):
return json.dumps(d, default=date_default)
def _convert_dict(ds):
if ds is None:
return ds
else:
if isinstance(ds, bytes):
# If I understand the sqlite doc correctly, this will always be utf8
ds = ds.decode('utf8')
return extract_dates(json.loads(ds))
def _adapt_bufs(bufs):
# this is *horrible*
# copy buffers into single list and pickle it:
if bufs and isinstance(bufs[0], (bytes, buffer)):
return sqlite3.Binary(pickle.dumps(map(bytes, bufs),-1))
elif bufs:
return bufs
else:
return None
def _convert_bufs(bs):
if bs is None:
return []
else:
return pickle.loads(bytes(bs))
#-----------------------------------------------------------------------------
# SQLiteDB class
#-----------------------------------------------------------------------------
class SQLiteDB(BaseDB):
"""SQLite3 TaskRecord backend."""
filename = Unicode('tasks.db', config=True,
help="""The filename of the sqlite task database. [default: 'tasks.db']""")
location = Unicode('', config=True,
help="""The directory containing the sqlite task database. The default
is to use the cluster_dir location.""")
table = Unicode("", config=True,
help="""The SQLite Table to use for storing tasks for this session. If unspecified,
a new table will be created with the Hub's IDENT. Specifying the table will result
in tasks from previous sessions being available via Clients' db_query and
get_result methods.""")
_db = Instance('sqlite3.Connection')
# the ordered list of column names
_keys = List(['msg_id' ,
'header' ,
'content',
'buffers',
'submitted',
'client_uuid' ,
'engine_uuid' ,
'started',
'completed',
'resubmitted',
'result_header' ,
'result_content' ,
'result_buffers' ,
'queue' ,
'pyin' ,
'pyout',
'pyerr',
'stdout',
'stderr',
])
# sqlite datatypes for checking that db is current format
_types = Dict({'msg_id' : 'text' ,
'header' : 'dict text',
'content' : 'dict text',
'buffers' : 'bufs blob',
'submitted' : 'timestamp',
'client_uuid' : 'text',
'engine_uuid' : 'text',
'started' : 'timestamp',
'completed' : 'timestamp',
'resubmitted' : 'timestamp',
'result_header' : 'dict text',
'result_content' : 'dict text',
'result_buffers' : 'bufs blob',
'queue' : 'text',
'pyin' : 'text',
'pyout' : 'text',
'pyerr' : 'text',
'stdout' : 'text',
'stderr' : 'text',
})
def __init__(self, **kwargs):
super(SQLiteDB, self).__init__(**kwargs)
if not self.table:
# use session, and prefix _, since starting with # is illegal
self.table = '_'+self.session.replace('-','_')
if not self.location:
# get current profile
from IPython.core.application import BaseIPythonApplication
if BaseIPythonApplication.initialized():
app = BaseIPythonApplication.instance()
if app.profile_dir is not None:
self.location = app.profile_dir.location
else:
self.location = u'.'
else:
self.location = u'.'
self._init_db()
# register db commit as 2s periodic callback
# to prevent clogging pipes
# assumes we are being run in a zmq ioloop app
loop = ioloop.IOLoop.instance()
pc = ioloop.PeriodicCallback(self._db.commit, 2000, loop)
pc.start()
def _defaults(self, keys=None):
"""create an empty record"""
d = {}
keys = self._keys if keys is None else keys
for key in keys:
d[key] = None
return d
def _check_table(self):
"""Ensure that an incorrect table doesn't exist
If a bad (old) table does exist, return False
"""
cursor = self._db.execute("PRAGMA table_info(%s)"%self.table)
lines = cursor.fetchall()
if not lines:
# table does not exist
return True
types = {}
keys = []
for line in lines:
keys.append(line[1])
types[line[1]] = line[2]
if self._keys != keys:
# key mismatch
self.log.warn('keys mismatch')
return False
for key in self._keys:
if types[key] != self._types[key]:
self.log.warn(
'type mismatch: %s: %s != %s'%(key,types[key],self._types[key])
)
return False
return True
def _init_db(self):
"""Connect to the database and get new session number."""
# register adapters
sqlite3.register_adapter(dict, _adapt_dict)
sqlite3.register_converter('dict', _convert_dict)
sqlite3.register_adapter(list, _adapt_bufs)
sqlite3.register_converter('bufs', _convert_bufs)
# connect to the db
dbfile = os.path.join(self.location, self.filename)
self._db = sqlite3.connect(dbfile, detect_types=sqlite3.PARSE_DECLTYPES,
# isolation_level = None)#,
cached_statements=64)
# print dir(self._db)
first_table = self.table
i=0
while not self._check_table():
i+=1
self.table = first_table+'_%i'%i
self.log.warn(
"Table %s exists and doesn't match db format, trying %s"%
(first_table,self.table)
)
self._db.execute("""CREATE TABLE IF NOT EXISTS %s
(msg_id text PRIMARY KEY,
header dict text,
content dict text,
buffers bufs blob,
submitted timestamp,
client_uuid text,
engine_uuid text,
started timestamp,
completed timestamp,
resubmitted timestamp,
result_header dict text,
result_content dict text,
result_buffers bufs blob,
queue text,
pyin text,
pyout text,
pyerr text,
stdout text,
stderr text)
"""%self.table)
self._db.commit()
def _dict_to_list(self, d):
"""turn a mongodb-style record dict into a list."""
return [ d[key] for key in self._keys ]
def _list_to_dict(self, line, keys=None):
"""Inverse of dict_to_list"""
keys = self._keys if keys is None else keys
d = self._defaults(keys)
for key,value in zip(keys, line):
d[key] = value
return d
def _render_expression(self, check):
"""Turn a mongodb-style search dict into an SQL query."""
expressions = []
args = []
skeys = set(check.keys())
skeys.difference_update(set(self._keys))
skeys.difference_update(set(['buffers', 'result_buffers']))
if skeys:
raise KeyError("Illegal testing key(s): %s"%skeys)
for name,sub_check in check.iteritems():
if isinstance(sub_check, dict):
for test,value in sub_check.iteritems():
try:
op = operators[test]
except KeyError:
raise KeyError("Unsupported operator: %r"%test)
if isinstance(op, tuple):
op, join = op
if value is None and op in null_operators:
expr = "%s %s"%null_operators[op]
else:
expr = "%s %s ?"%(name, op)
if isinstance(value, (tuple,list)):
if op in null_operators and any([v is None for v in value]):
# equality tests don't work with NULL
raise ValueError("Cannot use %r test with NULL values on SQLite backend"%test)
expr = '( %s )'%( join.join([expr]*len(value)) )
args.extend(value)
else:
args.append(value)
expressions.append(expr)
else:
# it's an equality check
if sub_check is None:
expressions.append("%s IS NULL")
else:
expressions.append("%s = ?"%name)
args.append(sub_check)
expr = " AND ".join(expressions)
return expr, args
def add_record(self, msg_id, rec):
"""Add a new Task Record, by msg_id."""
d = self._defaults()
d.update(rec)
d['msg_id'] = msg_id
line = self._dict_to_list(d)
tups = '(%s)'%(','.join(['?']*len(line)))
self._db.execute("INSERT INTO %s VALUES %s"%(self.table, tups), line)
# self._db.commit()
def get_record(self, msg_id):
"""Get a specific Task Record, by msg_id."""
cursor = self._db.execute("""SELECT * FROM %s WHERE msg_id==?"""%self.table, (msg_id,))
line = cursor.fetchone()
if line is None:
raise KeyError("No such msg: %r"%msg_id)
return self._list_to_dict(line)
def update_record(self, msg_id, rec):
"""Update the data in an existing record."""
query = "UPDATE %s SET "%self.table
sets = []
keys = sorted(rec.keys())
values = []
for key in keys:
sets.append('%s = ?'%key)
values.append(rec[key])
query += ', '.join(sets)
query += ' WHERE msg_id == ?'
values.append(msg_id)
self._db.execute(query, values)
# self._db.commit()
def drop_record(self, msg_id):
"""Remove a record from the DB."""
self._db.execute("""DELETE FROM %s WHERE msg_id==?"""%self.table, (msg_id,))
# self._db.commit()
def drop_matching_records(self, check):
"""Remove a record from the DB."""
expr,args = self._render_expression(check)
query = "DELETE FROM %s WHERE %s"%(self.table, expr)
self._db.execute(query,args)
# self._db.commit()
def find_records(self, check, keys=None):
"""Find records matching a query dict, optionally extracting subset of keys.
Returns list of matching records.
Parameters
----------
check: dict
mongodb-style query argument
keys: list of strs [optional]
if specified, the subset of keys to extract. msg_id will *always* be
included.
"""
if keys:
bad_keys = [ key for key in keys if key not in self._keys ]
if bad_keys:
raise KeyError("Bad record key(s): %s"%bad_keys)
if keys:
# ensure msg_id is present and first:
if 'msg_id' in keys:
keys.remove('msg_id')
keys.insert(0, 'msg_id')
req = ', '.join(keys)
else:
req = '*'
expr,args = self._render_expression(check)
query = """SELECT %s FROM %s WHERE %s"""%(req, self.table, expr)
cursor = self._db.execute(query, args)
matches = cursor.fetchall()
records = []
for line in matches:
rec = self._list_to_dict(line, keys)
records.append(rec)
return records
def get_history(self):
"""get all msg_ids, ordered by time submitted."""
query = """SELECT msg_id FROM %s ORDER by submitted ASC"""%self.table
cursor = self._db.execute(query)
# will be a list of length 1 tuples
return [ tup[0] for tup in cursor.fetchall()]
__all__ = ['SQLiteDB']