clonebundle: add a `filter_bundle_url` function

This function does nothing by default, but give extension the opportunity to
alter the URL, typically, this could be used to inject authentication token when
serving clone bundle for private repositories.

mercurial/bundlecaches.py

@@ -1,517 +1,538 b''
 # bundlecaches.py - utility to deal with pre-computed bundle for servers
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 import collections
 
 from typing import (
     cast,
 )
 
 from .i18n import _
 
 from .thirdparty import attr
 
 from . import (
     error,
     requirements as requirementsmod,
     sslutil,
     util,
 )
 from .utils import stringutil
 
 urlreq = util.urlreq
 
 CB_MANIFEST_FILE = b'clonebundles.manifest'
 
+
 def get_manifest(repo):
-    return repo.vfs.tryread(CB_MANIFEST_FILE)
+    """get the bundle manifest to be served to a client from a server"""
+    raw_text = repo.vfs.tryread(CB_MANIFEST_FILE)
+    entries = [e.split(b' ', 1) for e in raw_text.splitlines()]
+
+    new_lines = []
+    for e in entries:
+        url = alter_bundle_url(repo, e[0])
+        if len(e) == 1:
+            line = url + b'\n'
+        else:
+            line = b"%s %s\n" % (url, e[1])
+        new_lines.append(line)
+    return b''.join(new_lines)
+
+
+def alter_bundle_url(repo, url):
+    """a function that exist to help extension and hosting to alter the url
+
+    This will typically be used to inject authentication information in the url
+    of cached bundles."""
+    return url
 
 
 @attr.s
 class bundlespec:
     compression = attr.ib()
     wirecompression = attr.ib()
     version = attr.ib()
     wireversion = attr.ib()
     # parameters explicitly overwritten by the config or the specification
     _explicit_params = attr.ib()
     # default parameter for the version
     #
     # Keeping it separated is useful to check what was actually overwritten.
     _default_opts = attr.ib()
 
     @property
     def params(self):
         return collections.ChainMap(self._explicit_params, self._default_opts)
 
     @property
     def contentopts(self):
         # kept for Backward Compatibility concerns.
         return self.params
 
     def set_param(self, key, value, overwrite=True):
         """Set a bundle parameter value.
 
         Will only overwrite if overwrite is true"""
         if overwrite or key not in self._explicit_params:
             self._explicit_params[key] = value
 
 
 # Maps bundle version human names to changegroup versions.
 _bundlespeccgversions = {
     b'v1': b'01',
     b'v2': b'02',
     b'v3': b'03',
     b'packed1': b's1',
     b'bundle2': b'02',  # legacy
 }
 
 # Maps bundle version with content opts to choose which part to bundle
 _bundlespeccontentopts = {
     b'v1': {
         b'changegroup': True,
         b'cg.version': b'01',
         b'obsolescence': False,
         b'phases': False,
         b'tagsfnodescache': False,
         b'revbranchcache': False,
     },
     b'v2': {
         b'changegroup': True,
         b'cg.version': b'02',
         b'obsolescence': False,
         b'phases': False,
         b'tagsfnodescache': True,
         b'revbranchcache': True,
     },
     b'v3': {
         b'changegroup': True,
         b'cg.version': b'03',
         b'obsolescence': False,
         b'phases': True,
         b'tagsfnodescache': True,
         b'revbranchcache': True,
     },
     b'streamv2': {
         b'changegroup': False,
         b'cg.version': b'02',
         b'obsolescence': False,
         b'phases': False,
         b"streamv2": True,
         b'tagsfnodescache': False,
         b'revbranchcache': False,
     },
     b'streamv3-exp': {
         b'changegroup': False,
         b'cg.version': b'03',
         b'obsolescence': False,
         b'phases': False,
         b"streamv3-exp": True,
         b'tagsfnodescache': False,
         b'revbranchcache': False,
     },
     b'packed1': {
         b'cg.version': b's1',
     },
     b'bundle2': {  # legacy
         b'cg.version': b'02',
     },
 }
 _bundlespeccontentopts[b'bundle2'] = _bundlespeccontentopts[b'v2']
 
 _bundlespecvariants = {b"streamv2": {}}
 
 # Compression engines allowed in version 1. THIS SHOULD NEVER CHANGE.
 _bundlespecv1compengines = {b'gzip', b'bzip2', b'none'}
 
 
 def param_bool(key, value):
     """make a boolean out of a parameter value"""
     b = stringutil.parsebool(value)
     if b is None:
         msg = _(b"parameter %s should be a boolean ('%s')")
         msg %= (key, value)
         raise error.InvalidBundleSpecification(msg)
     return b
 
 
 # mapping of known parameter name need their value processed
 bundle_spec_param_processing = {
     b"obsolescence": param_bool,
     b"obsolescence-mandatory": param_bool,
     b"phases": param_bool,
 }
 
 
 def _parseparams(s):
     """parse bundlespec parameter section
 
     input: "comp-version;params" string
 
     return: (spec; {param_key: param_value})
     """
     if b';' not in s:
         return s, {}
 
     params = {}
     version, paramstr = s.split(b';', 1)
 
     err = _(b'invalid bundle specification: missing "=" in parameter: %s')
     for p in paramstr.split(b';'):
         if b'=' not in p:
             msg = err % p
             raise error.InvalidBundleSpecification(msg)
 
         key, value = p.split(b'=', 1)
         key = urlreq.unquote(key)
         value = urlreq.unquote(value)
         process = bundle_spec_param_processing.get(key)
         if process is not None:
             value = process(key, value)
         params[key] = value
 
     return version, params
 
 
 def parsebundlespec(repo, spec, strict=True):
     """Parse a bundle string specification into parts.
 
     Bundle specifications denote a well-defined bundle/exchange format.
     The content of a given specification should not change over time in
     order to ensure that bundles produced by a newer version of Mercurial are
     readable from an older version.
 
     The string currently has the form:
 
        <compression>-<type>[;<parameter0>[;<parameter1>]]
 
     Where <compression> is one of the supported compression formats
     and <type> is (currently) a version string. A ";" can follow the type and
     all text afterwards is interpreted as URI encoded, ";" delimited key=value
     pairs.
 
     If ``strict`` is True (the default) <compression> is required. Otherwise,
     it is optional.
 
     Returns a bundlespec object of (compression, version, parameters).
     Compression will be ``None`` if not in strict mode and a compression isn't
     defined.
 
     An ``InvalidBundleSpecification`` is raised when the specification is
     not syntactically well formed.
 
     An ``UnsupportedBundleSpecification`` is raised when the compression or
     bundle type/version is not recognized.
 
     Note: this function will likely eventually return a more complex data
     structure, including bundle2 part information.
     """
     if strict and b'-' not in spec:
         raise error.InvalidBundleSpecification(
             _(
                 b'invalid bundle specification; '
                 b'must be prefixed with compression: %s'
             )
             % spec
         )
 
     pre_args = spec.split(b';', 1)[0]
     if b'-' in pre_args:
         compression, version = spec.split(b'-', 1)
 
         if compression not in util.compengines.supportedbundlenames:
             raise error.UnsupportedBundleSpecification(
                 _(b'%s compression is not supported') % compression
             )
 
         version, params = _parseparams(version)
 
         if version not in _bundlespeccontentopts:
             raise error.UnsupportedBundleSpecification(
                 _(b'%s is not a recognized bundle version') % version
             )
     else:
         # Value could be just the compression or just the version, in which
         # case some defaults are assumed (but only when not in strict mode).
         assert not strict
 
         spec, params = _parseparams(spec)
 
         if spec in util.compengines.supportedbundlenames:
             compression = spec
             version = b'v1'
             # Generaldelta repos require v2.
             if requirementsmod.GENERALDELTA_REQUIREMENT in repo.requirements:
                 version = b'v2'
             elif requirementsmod.REVLOGV2_REQUIREMENT in repo.requirements:
                 version = b'v2'
             # Modern compression engines require v2.
             if compression not in _bundlespecv1compengines:
                 version = b'v2'
         elif spec in _bundlespeccontentopts:
             if spec == b'packed1':
                 compression = b'none'
             else:
                 compression = b'bzip2'
             version = spec
         else:
             raise error.UnsupportedBundleSpecification(
                 _(b'%s is not a recognized bundle specification') % spec
             )
 
     # Bundle version 1 only supports a known set of compression engines.
     if version == b'v1' and compression not in _bundlespecv1compengines:
         raise error.UnsupportedBundleSpecification(
             _(b'compression engine %s is not supported on v1 bundles')
             % compression
         )
 
     # The specification for packed1 can optionally declare the data formats
     # required to apply it. If we see this metadata, compare against what the
     # repo supports and error if the bundle isn't compatible.
     if version == b'packed1' and b'requirements' in params:
         requirements = set(cast(bytes, params[b'requirements']).split(b','))
         missingreqs = requirements - requirementsmod.STREAM_FIXED_REQUIREMENTS
         if missingreqs:
             raise error.UnsupportedBundleSpecification(
                 _(b'missing support for repository features: %s')
                 % b', '.join(sorted(missingreqs))
             )
 
     # Compute contentopts based on the version
     if b"stream" in params:
         # This case is fishy as this mostly derails the version selection
         # mechanism. `stream` bundles are quite specific and used differently
         # as "normal" bundles.
         #
         # (we should probably define a cleaner way to do this and raise a
         # warning when the old way is encountered)
         if params[b"stream"] == b"v2":
             version = b"streamv2"
         if params[b"stream"] == b"v3-exp":
             version = b"streamv3-exp"
     contentopts = _bundlespeccontentopts.get(version, {}).copy()
     if version == b"streamv2" or version == b"streamv3-exp":
         # streamv2 have been reported as "v2" for a while.
         version = b"v2"
 
     engine = util.compengines.forbundlename(compression)
     compression, wirecompression = engine.bundletype()
     wireversion = _bundlespeccontentopts[version][b'cg.version']
 
     return bundlespec(
         compression, wirecompression, version, wireversion, params, contentopts
     )
 
 
 def parseclonebundlesmanifest(repo, s):
     """Parses the raw text of a clone bundles manifest.
 
     Returns a list of dicts. The dicts have a ``URL`` key corresponding
     to the URL and other keys are the attributes for the entry.
     """
     m = []
     for line in s.splitlines():
         fields = line.split()
         if not fields:
             continue
         attrs = {b'URL': fields[0]}
         for rawattr in fields[1:]:
             key, value = rawattr.split(b'=', 1)
             key = util.urlreq.unquote(key)
             value = util.urlreq.unquote(value)
             attrs[key] = value
 
             # Parse BUNDLESPEC into components. This makes client-side
             # preferences easier to specify since you can prefer a single
             # component of the BUNDLESPEC.
             if key == b'BUNDLESPEC':
                 try:
                     bundlespec = parsebundlespec(repo, value)
                     attrs[b'COMPRESSION'] = bundlespec.compression
                     attrs[b'VERSION'] = bundlespec.version
                 except error.InvalidBundleSpecification:
                     pass
                 except error.UnsupportedBundleSpecification:
                     pass
 
         m.append(attrs)
 
     return m
 
 
 def isstreamclonespec(bundlespec):
     # Stream clone v1
     if bundlespec.wirecompression == b'UN' and bundlespec.wireversion == b's1':
         return True
 
     # Stream clone v2
     if (
         bundlespec.wirecompression == b'UN'
         and bundlespec.wireversion == b'02'
         and (
             bundlespec.contentopts.get(b'streamv2')
             or bundlespec.contentopts.get(b'streamv3-exp')
         )
     ):
         return True
 
     return False
 
 
 def filterclonebundleentries(repo, entries, streamclonerequested=False):
     """Remove incompatible clone bundle manifest entries.
 
     Accepts a list of entries parsed with ``parseclonebundlesmanifest``
     and returns a new list consisting of only the entries that this client
     should be able to apply.
 
     There is no guarantee we'll be able to apply all returned entries because
     the metadata we use to filter on may be missing or wrong.
     """
     newentries = []
     for entry in entries:
         spec = entry.get(b'BUNDLESPEC')
         if spec:
             try:
                 bundlespec = parsebundlespec(repo, spec, strict=True)
 
                 # If a stream clone was requested, filter out non-streamclone
                 # entries.
                 if streamclonerequested and not isstreamclonespec(bundlespec):
                     repo.ui.debug(
                         b'filtering %s because not a stream clone\n'
                         % entry[b'URL']
                     )
                     continue
 
             except error.InvalidBundleSpecification as e:
                 repo.ui.debug(stringutil.forcebytestr(e) + b'\n')
                 continue
             except error.UnsupportedBundleSpecification as e:
                 repo.ui.debug(
                     b'filtering %s because unsupported bundle '
                     b'spec: %s\n' % (entry[b'URL'], stringutil.forcebytestr(e))
                 )
                 continue
         # If we don't have a spec and requested a stream clone, we don't know
         # what the entry is so don't attempt to apply it.
         elif streamclonerequested:
             repo.ui.debug(
                 b'filtering %s because cannot determine if a stream '
                 b'clone bundle\n' % entry[b'URL']
             )
             continue
 
         if b'REQUIRESNI' in entry and not sslutil.hassni:
             repo.ui.debug(
                 b'filtering %s because SNI not supported\n' % entry[b'URL']
             )
             continue
 
         if b'REQUIREDRAM' in entry:
             try:
                 requiredram = util.sizetoint(entry[b'REQUIREDRAM'])
             except error.ParseError:
                 repo.ui.debug(
                     b'filtering %s due to a bad REQUIREDRAM attribute\n'
                     % entry[b'URL']
                 )
                 continue
             actualram = repo.ui.estimatememory()
             if actualram is not None and actualram * 0.66 < requiredram:
                 repo.ui.debug(
                     b'filtering %s as it needs more than 2/3 of system memory\n'
                     % entry[b'URL']
                 )
                 continue
 
         newentries.append(entry)
 
     return newentries
 
 
 class clonebundleentry:
     """Represents an item in a clone bundles manifest.
 
     This rich class is needed to support sorting since sorted() in Python 3
     doesn't support ``cmp`` and our comparison is complex enough that ``key=``
     won't work.
     """
 
     def __init__(self, value, prefers):
         self.value = value
         self.prefers = prefers
 
     def _cmp(self, other):
         for prefkey, prefvalue in self.prefers:
             avalue = self.value.get(prefkey)
             bvalue = other.value.get(prefkey)
 
             # Special case for b missing attribute and a matches exactly.
             if avalue is not None and bvalue is None and avalue == prefvalue:
                 return -1
 
             # Special case for a missing attribute and b matches exactly.
             if bvalue is not None and avalue is None and bvalue == prefvalue:
                 return 1
 
             # We can't compare unless attribute present on both.
             if avalue is None or bvalue is None:
                 continue
 
             # Same values should fall back to next attribute.
             if avalue == bvalue:
                 continue
 
             # Exact matches come first.
             if avalue == prefvalue:
                 return -1
             if bvalue == prefvalue:
                 return 1
 
             # Fall back to next attribute.
             continue
 
         # If we got here we couldn't sort by attributes and prefers. Fall
         # back to index order.
         return 0
 
     def __lt__(self, other):
         return self._cmp(other) < 0
 
     def __gt__(self, other):
         return self._cmp(other) > 0
 
     def __eq__(self, other):
         return self._cmp(other) == 0
 
     def __le__(self, other):
         return self._cmp(other) <= 0
 
     def __ge__(self, other):
         return self._cmp(other) >= 0
 
     def __ne__(self, other):
         return self._cmp(other) != 0
 
 
 def sortclonebundleentries(ui, entries):
     prefers = ui.configlist(b'ui', b'clonebundleprefers')
     if not prefers:
         return list(entries)
 
     def _split(p):
         if b'=' not in p:
             hint = _(b"each comma separated item should be key=value pairs")
             raise error.Abort(
                 _(b"invalid ui.clonebundleprefers item: %s") % p, hint=hint
             )
         return p.split(b'=', 1)
 
     prefers = [_split(p) for p in prefers]
 
     items = sorted(clonebundleentry(v, prefers) for v in entries)
     return [i.value for i in items]