view tests/test-check-interfaces.py @ 37631:2f626233859b

wireproto: implement batching on peer executor interface

This is a bit more complicated than non-batch requests because we
need to buffer sends until the last request arrives *and* we need
to support resolving futures as data arrives from the remote.

In a classical concurrent.futures executor model, the future
"starts" as soon as it is submitted. However, we have nothing to
start until the last command is submitted.

If we did nothing, calling result() would deadlock, since the future
hasn't "started." So in the case where we queue the command, we return
a special future type whose result() will trigger sendcommands().
This eliminates the deadlock potential. It also serves as a check
against callers who may be calling result() prematurely, as it will
prevent any subsequent callcommands() from working. This behavior
is slightly annoying and a bit restrictive. But it's the world
that half duplex connections forces on us.

In order to support streaming responses, we were previously using
a generator. But with a futures-based API, we're using futures
and not generators. So in order to get streaming, we need a
background thread to read data from the server.

The approach taken in this patch is to leverage the ThreadPoolExecutor
from concurrent.futures for managing a background thread. We create
an executor and future that resolves when all response data is
processed (or an error occurs). When exiting the context manager,
we wait on that background reading before returning.

I was hoping we could manually spin up a threading.Thread and this
would be simple. But I ran into a few deadlocks when implementing.
After looking at the source code to concurrent.futures, I figured
it would just be easier to use a ThreadPoolExecutor than implement
all the code needed to manually manage a thread.

To prove this works, a use of the batch API in discovery has been
updated.

Differential Revision: https://phab.mercurial-scm.org/D3269

# Test that certain objects conform to well-defined interfaces.

from __future__ import absolute_import, print_function

import os

from mercurial.thirdparty.zope import (
    interface as zi,
)
from mercurial.thirdparty.zope.interface import (
    verify as ziverify,
)
from mercurial import (
    bundlerepo,
    filelog,
    httppeer,
    localrepo,
    repository,
    sshpeer,
    statichttprepo,
    ui as uimod,
    unionrepo,
    vfs as vfsmod,
    wireprotoserver,
    wireprototypes,
    wireprotov1peer,
    wireprotov2server,
)

rootdir = os.path.normpath(os.path.join(os.path.dirname(__file__), '..'))

def checkzobject(o, allowextra=False):
    """Verify an object with a zope interface."""
    ifaces = zi.providedBy(o)
    if not ifaces:
        print('%r does not provide any zope interfaces' % o)
        return

    # Run zope.interface's built-in verification routine. This verifies that
    # everything that is supposed to be present is present.
    for iface in ifaces:
        ziverify.verifyObject(iface, o)

    if allowextra:
        return

    # Now verify that the object provides no extra public attributes that
    # aren't declared as part of interfaces.
    allowed = set()
    for iface in ifaces:
        allowed |= set(iface.names(all=True))

    public = {a for a in dir(o) if not a.startswith('_')}

    for attr in sorted(public - allowed):
        print('public attribute not declared in interfaces: %s.%s' % (
            o.__class__.__name__, attr))

# Facilitates testing localpeer.
class dummyrepo(object):
    def __init__(self):
        self.ui = uimod.ui()
    def filtered(self, name):
        pass
    def _restrictcapabilities(self, caps):
        pass

class dummyopener(object):
    handlers = []

# Facilitates testing sshpeer without requiring a server.
class badpeer(httppeer.httppeer):
    def __init__(self):
        super(badpeer, self).__init__(None, None, None, dummyopener(), None,
                                      None)
        self.badattribute = True

    def badmethod(self):
        pass

class dummypipe(object):
    def close(self):
        pass

def main():
    ui = uimod.ui()
    # Needed so we can open a local repo with obsstore without a warning.
    ui.setconfig('experimental', 'evolution.createmarkers', True)

    checkzobject(badpeer())

    ziverify.verifyClass(repository.ipeerbaselegacycommands,
                         httppeer.httppeer)
    checkzobject(httppeer.httppeer(None, None, None, dummyopener(), None, None))

    ziverify.verifyClass(repository.ipeerconnection,
                         httppeer.httpv2peer)
    ziverify.verifyClass(repository.ipeercapabilities,
                         httppeer.httpv2peer)
    checkzobject(httppeer.httpv2peer(None, '', None, None, None, None))

    ziverify.verifyClass(repository.ipeerbase,
                         localrepo.localpeer)
    checkzobject(localrepo.localpeer(dummyrepo()))

    ziverify.verifyClass(repository.ipeercommandexecutor,
                         localrepo.localcommandexecutor)
    checkzobject(localrepo.localcommandexecutor(None))

    ziverify.verifyClass(repository.ipeercommandexecutor,
                         wireprotov1peer.peerexecutor)
    checkzobject(wireprotov1peer.peerexecutor(None))

    ziverify.verifyClass(repository.ipeerbaselegacycommands,
                         sshpeer.sshv1peer)
    checkzobject(sshpeer.sshv1peer(ui, 'ssh://localhost/foo', None, dummypipe(),
                                   dummypipe(), None, None))

    ziverify.verifyClass(repository.ipeerbaselegacycommands,
                         sshpeer.sshv2peer)
    checkzobject(sshpeer.sshv2peer(ui, 'ssh://localhost/foo', None, dummypipe(),
                                   dummypipe(), None, None))

    ziverify.verifyClass(repository.ipeerbase, bundlerepo.bundlepeer)
    checkzobject(bundlerepo.bundlepeer(dummyrepo()))

    ziverify.verifyClass(repository.ipeerbase, statichttprepo.statichttppeer)
    checkzobject(statichttprepo.statichttppeer(dummyrepo()))

    ziverify.verifyClass(repository.ipeerbase, unionrepo.unionpeer)
    checkzobject(unionrepo.unionpeer(dummyrepo()))

    ziverify.verifyClass(repository.completelocalrepository,
                         localrepo.localrepository)
    repo = localrepo.localrepository(ui, rootdir)
    checkzobject(repo)

    ziverify.verifyClass(wireprototypes.baseprotocolhandler,
                         wireprotoserver.sshv1protocolhandler)
    ziverify.verifyClass(wireprototypes.baseprotocolhandler,
                         wireprotoserver.sshv2protocolhandler)
    ziverify.verifyClass(wireprototypes.baseprotocolhandler,
                         wireprotoserver.httpv1protocolhandler)
    ziverify.verifyClass(wireprototypes.baseprotocolhandler,
                         wireprotov2server.httpv2protocolhandler)

    sshv1 = wireprotoserver.sshv1protocolhandler(None, None, None)
    checkzobject(sshv1)
    sshv2 = wireprotoserver.sshv2protocolhandler(None, None, None)
    checkzobject(sshv2)

    httpv1 = wireprotoserver.httpv1protocolhandler(None, None, None)
    checkzobject(httpv1)
    httpv2 = wireprotov2server.httpv2protocolhandler(None, None)
    checkzobject(httpv2)

    ziverify.verifyClass(repository.ifilestorage, filelog.filelog)

    vfs = vfsmod.vfs('.')
    fl = filelog.filelog(vfs, 'dummy.i')
    checkzobject(fl, allowextra=True)

main()