comparison mercurial/wireprotov1peer.py @ 37630:e1b32dc4646c

wireproto: implement command executor interface for version 1 peers

Now that we've defined our new interface for issuing commands,
let's implement it.

We add the interface to the base peer interface. This means all
peer types must implement it.

The only peer types that we have are the local peer in localrepo
and a shared wire peer for version 1 of the wire protocol.

The local peer implementation is pretty straightforward. We
don't do anything fancy and just return a resolved future with
the result of a method call. This is similar to what
localiterbatcher does.

The wire protocol version 1 implementation is a bit more complicated
and is a more robust implementation.

The wire executor queues commands by default. And because the new
executor interface always allows multiple commands but not all version
1 commands are @batchable, it has to check that the requested commands
are batchable if multiple commands are being requested.

The wire executor currently only supports executing a single command.
This is for simplicity reasons. Support for multiple commands will
be added in a separate commit.

To prove the new interface works, a call to the "known" command
during discovery has been updated to use the new API.

It's worth noting that both implementations require a method having
the command name to exist on the peer. There is at least one caller
in core that don't have a method calls peer._call() directly. We
may need to shore up the requirements later...

Differential Revision: https://phab.mercurial-scm.org/D3268

37629:fa0382088993

# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

import hashlib

from .i18n import _
from .node import (
    bin,
)

from . import (
    bundle2,
    changegroup as changegroupmod,
    encoding,
    error,

                        for k, v in argsdict.iteritems())
        cmds.append('%s %s' % (op, args))

    return ';'.join(cmds)

class wirepeer(repository.legacypeer):
    """Client-side interface for communicating with a peer repository.

    Methods commonly call wire protocol commands of the same name.

    See also httppeer.py and sshpeer.py for protocol-specific
    implementations of this interface.
    """
    # Begin of ipeercommands interface.

    def iterbatch(self):
        return remoteiterbatcher(self)

37630:e1b32dc4646c

# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

import hashlib
import sys

from .i18n import _
from .node import (
    bin,
)
from .thirdparty.zope import (
    interface as zi,
)
from . import (
    bundle2,
    changegroup as changegroupmod,
    encoding,
    error,

                        for k, v in argsdict.iteritems())
        cmds.append('%s %s' % (op, args))

    return ';'.join(cmds)

@zi.implementer(repository.ipeercommandexecutor)
class peerexecutor(object):
    def __init__(self, peer):
        self._peer = peer
        self._sent = False
        self._closed = False
        self._calls = []

    def __enter__(self):
        return self

    def __exit__(self, exctype, excvalee, exctb):
        self.close()

    def callcommand(self, command, args):
        if self._sent:
            raise error.ProgrammingError('callcommand() cannot be used '
                                         'after commands are sent')

        if self._closed:
            raise error.ProgrammingError('callcommand() cannot be used '
                                         'after close()')

        # Commands are dispatched through methods on the peer.
        fn = getattr(self._peer, pycompat.sysstr(command), None)

        if not fn:
            raise error.ProgrammingError(
                'cannot call command %s: method of same name not available '
                'on peer' % command)

        # Commands are either batchable or they aren't. If a command
        # isn't batchable, we send it immediately because the executor
        # can no longer accept new commands after a non-batchable command.
        # If a command is batchable, we queue it for later.

        if getattr(fn, 'batchable', False):
            pass
        else:
            if self._calls:
                raise error.ProgrammingError(
                    '%s is not batchable and cannot be called on a command '
                    'executor along with other commands' % command)

        # We don't support batching yet. So resolve it immediately.
        f = pycompat.futures.Future()
        self._calls.append((command, args, fn, f))
        self.sendcommands()
        return f

    def sendcommands(self):
        if self._sent:
            return

        if not self._calls:
            return

        self._sent = True

        calls = self._calls
        # Mainly to destroy references to futures.
        self._calls = None

        if len(calls) == 1:
            command, args, fn, f = calls[0]

            # Future was cancelled. Ignore it.
            if not f.set_running_or_notify_cancel():
                return

            try:
                result = fn(**pycompat.strkwargs(args))
            except Exception:
                f.set_exception_info(*sys.exc_info()[1:])
            else:
                f.set_result(result)

            return

        raise error.ProgrammingError('support for multiple commands not '
                                     'yet implemented')

    def close(self):
        self.sendcommands()

        self._closed = True

class wirepeer(repository.legacypeer):
    """Client-side interface for communicating with a peer repository.

    Methods commonly call wire protocol commands of the same name.

    See also httppeer.py and sshpeer.py for protocol-specific
    implementations of this interface.
    """
    def commandexecutor(self):
        return peerexecutor(self)

    # Begin of ipeercommands interface.

    def iterbatch(self):
        return remoteiterbatcher(self)