Mercurial > hg
view tests/test-batching.py @ 29859:a1092e2d70a3
help: internals topic for wire protocol
The Mercurial wire protocol is under-documented. This includes a lack
of source docstrings and comments as well as pages on the official
wiki.
This patch adds the beginnings of "internals" documentation on the
wire protocol.
The documentation should have nearly complete coverage on the
lower-level parts of the protocol, such as the different transport
mechanims, how commands and arguments are sent, capabilities, and,
of course, the commands themselves.
As part of writing this documentation, I discovered a number of
deficiencies in the protocol and bugs in the implementation. I've
started sending patches for some of the issues. I hope to send a lot
more.
This patch starts with the scaffolding for a new internals page.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Mon, 22 Aug 2016 19:46:39 -0700 |
parents | 544908ae36ce |
children | e2fc2122029c |
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# test-batching.py - tests for transparent command batching # # Copyright 2011 Peter Arrenbrecht <peter@arrenbrecht.ch> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from __future__ import absolute_import, print_function from mercurial import ( peer, wireproto, ) # equivalent of repo.repository class thing(object): def hello(self): return "Ready." # equivalent of localrepo.localrepository class localthing(thing): def foo(self, one, two=None): if one: return "%s and %s" % (one, two,) return "Nope" def bar(self, b, a): return "%s und %s" % (b, a,) def greet(self, name=None): return "Hello, %s" % name def batch(self): '''Support for local batching.''' return peer.localbatch(self) # usage of "thing" interface def use(it): # Direct call to base method shared between client and server. print(it.hello()) # Direct calls to proxied methods. They cause individual roundtrips. print(it.foo("Un", two="Deux")) print(it.bar("Eins", "Zwei")) # Batched call to a couple of (possibly proxied) methods. batch = it.batch() # The calls return futures to eventually hold results. foo = batch.foo(one="One", two="Two") foo2 = batch.foo(None) bar = batch.bar("Eins", "Zwei") # We can call non-batchable proxy methods, but the break the current batch # request and cause additional roundtrips. greet = batch.greet(name="John Smith") # We can also add local methods into the mix, but they break the batch too. hello = batch.hello() bar2 = batch.bar(b="Uno", a="Due") # Only now are all the calls executed in sequence, with as few roundtrips # as possible. batch.submit() # After the call to submit, the futures actually contain values. print(foo.value) print(foo2.value) print(bar.value) print(greet.value) print(hello.value) print(bar2.value) # local usage mylocal = localthing() print() print("== Local") use(mylocal) # demo remoting; mimicks what wireproto and HTTP/SSH do # shared def escapearg(plain): return (plain .replace(':', '::') .replace(',', ':,') .replace(';', ':;') .replace('=', ':=')) def unescapearg(escaped): return (escaped .replace(':=', '=') .replace(':;', ';') .replace(':,', ',') .replace('::', ':')) # server side # equivalent of wireproto's global functions class server(object): def __init__(self, local): self.local = local def _call(self, name, args): args = dict(arg.split('=', 1) for arg in args) return getattr(self, name)(**args) def perform(self, req): print("REQ:", req) name, args = req.split('?', 1) args = args.split('&') vals = dict(arg.split('=', 1) for arg in args) res = getattr(self, name)(**vals) print(" ->", res) return res def batch(self, cmds): res = [] for pair in cmds.split(';'): name, args = pair.split(':', 1) vals = {} for a in args.split(','): if a: n, v = a.split('=') vals[n] = unescapearg(v) res.append(escapearg(getattr(self, name)(**vals))) return ';'.join(res) def foo(self, one, two): return mangle(self.local.foo(unmangle(one), unmangle(two))) def bar(self, b, a): return mangle(self.local.bar(unmangle(b), unmangle(a))) def greet(self, name): return mangle(self.local.greet(unmangle(name))) myserver = server(mylocal) # local side # equivalent of wireproto.encode/decodelist, that is, type-specific marshalling # here we just transform the strings a bit to check we're properly en-/decoding def mangle(s): return ''.join(chr(ord(c) + 1) for c in s) def unmangle(s): return ''.join(chr(ord(c) - 1) for c in s) # equivalent of wireproto.wirerepository and something like http's wire format class remotething(thing): def __init__(self, server): self.server = server def _submitone(self, name, args): req = name + '?' + '&'.join(['%s=%s' % (n, v) for n, v in args]) return self.server.perform(req) def _submitbatch(self, cmds): req = [] for name, args in cmds: args = ','.join(n + '=' + escapearg(v) for n, v in args) req.append(name + ':' + args) req = ';'.join(req) res = self._submitone('batch', [('cmds', req,)]) return res.split(';') def batch(self): return wireproto.remotebatch(self) @peer.batchable def foo(self, one, two=None): if not one: yield "Nope", None encargs = [('one', mangle(one),), ('two', mangle(two),)] encresref = peer.future() yield encargs, encresref yield unmangle(encresref.value) @peer.batchable def bar(self, b, a): encresref = peer.future() yield [('b', mangle(b),), ('a', mangle(a),)], encresref yield unmangle(encresref.value) # greet is coded directly. It therefore does not support batching. If it # does appear in a batch, the batch is split around greet, and the call to # greet is done in its own roundtrip. def greet(self, name=None): return unmangle(self._submitone('greet', [('name', mangle(name),)])) # demo remote usage myproxy = remotething(myserver) print() print("== Remote") use(myproxy)