Mercurial > hg
view doc/gendoc.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
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Fri, 13 Apr 2018 11:02:34 -0700 |
parents | ff874d34c856 |
children | 170926caf44c |
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#!/usr/bin/env python """usage: %s DOC ... where DOC is the name of a document """ from __future__ import absolute_import import os import sys import textwrap # This script is executed during installs and may not have C extensions # available. Relax C module requirements. os.environ['HGMODULEPOLICY'] = 'allow' # import from the live mercurial repo sys.path.insert(0, "..") from mercurial import demandimport; demandimport.enable() # Load util so that the locale path is set by i18n.setdatapath() before # calling _(). from mercurial import util util.datapath from mercurial import ( commands, extensions, help, minirst, ui as uimod, ) from mercurial.i18n import ( gettext, _, ) table = commands.table globalopts = commands.globalopts helptable = help.helptable loaddoc = help.loaddoc def get_desc(docstr): if not docstr: return "", "" # sanitize docstr = docstr.strip("\n") docstr = docstr.rstrip() shortdesc = docstr.splitlines()[0].strip() i = docstr.find("\n") if i != -1: desc = docstr[i + 2:] else: desc = shortdesc desc = textwrap.dedent(desc) return (shortdesc, desc) def get_opts(opts): for opt in opts: if len(opt) == 5: shortopt, longopt, default, desc, optlabel = opt else: shortopt, longopt, default, desc = opt optlabel = _("VALUE") allopts = [] if shortopt: allopts.append("-%s" % shortopt) if longopt: allopts.append("--%s" % longopt) if isinstance(default, list): allopts[-1] += " <%s[+]>" % optlabel elif (default is not None) and not isinstance(default, bool): allopts[-1] += " <%s>" % optlabel if '\n' in desc: # only remove line breaks and indentation desc = ' '.join(l.lstrip() for l in desc.split('\n')) desc += default and _(" (default: %s)") % default or "" yield (", ".join(allopts), desc) def get_cmd(cmd, cmdtable): d = {} attr = cmdtable[cmd] cmds = cmd.lstrip("^").split("|") d['cmd'] = cmds[0] d['aliases'] = cmd.split("|")[1:] d['desc'] = get_desc(gettext(attr[0].__doc__)) d['opts'] = list(get_opts(attr[1])) s = 'hg ' + cmds[0] if len(attr) > 2: if not attr[2].startswith('hg'): s += ' ' + attr[2] else: s = attr[2] d['synopsis'] = s.strip() return d def showdoc(ui): # print options ui.write(minirst.section(_("Options"))) multioccur = False for optstr, desc in get_opts(globalopts): ui.write("%s\n %s\n\n" % (optstr, desc)) if optstr.endswith("[+]>"): multioccur = True if multioccur: ui.write(_("\n[+] marked option can be specified multiple times\n")) ui.write("\n") # print cmds ui.write(minirst.section(_("Commands"))) commandprinter(ui, table, minirst.subsection) # print help topics # The config help topic is included in the hgrc.5 man page. helpprinter(ui, helptable, minirst.section, exclude=['config']) ui.write(minirst.section(_("Extensions"))) ui.write(_("This section contains help for extensions that are " "distributed together with Mercurial. Help for other " "extensions is available in the help system.")) ui.write(("\n\n" ".. contents::\n" " :class: htmlonly\n" " :local:\n" " :depth: 1\n\n")) for extensionname in sorted(allextensionnames()): mod = extensions.load(ui, extensionname, None) ui.write(minirst.subsection(extensionname)) ui.write("%s\n\n" % gettext(mod.__doc__)) cmdtable = getattr(mod, 'cmdtable', None) if cmdtable: ui.write(minirst.subsubsection(_('Commands'))) commandprinter(ui, cmdtable, minirst.subsubsubsection) def showtopic(ui, topic): extrahelptable = [ (["common"], '', loaddoc('common')), (["hg.1"], '', loaddoc('hg.1')), (["hg-ssh.8"], '', loaddoc('hg-ssh.8')), (["hgignore.5"], '', loaddoc('hgignore.5')), (["hgrc.5"], '', loaddoc('hgrc.5')), (["hgignore.5.gendoc"], '', loaddoc('hgignore')), (["hgrc.5.gendoc"], '', loaddoc('config')), ] helpprinter(ui, helptable + extrahelptable, None, include=[topic]) def helpprinter(ui, helptable, sectionfunc, include=[], exclude=[]): for names, sec, doc in helptable: if exclude and names[0] in exclude: continue if include and names[0] not in include: continue for name in names: ui.write(".. _%s:\n" % name) ui.write("\n") if sectionfunc: ui.write(sectionfunc(sec)) if callable(doc): doc = doc(ui) ui.write(doc) ui.write("\n") def commandprinter(ui, cmdtable, sectionfunc): h = {} for c, attr in cmdtable.items(): f = c.split("|")[0] f = f.lstrip("^") h[f] = c cmds = h.keys() cmds.sort() for f in cmds: if f.startswith("debug"): continue d = get_cmd(h[f], cmdtable) ui.write(sectionfunc(d['cmd'])) # short description ui.write(d['desc'][0]) # synopsis ui.write("::\n\n") synopsislines = d['synopsis'].splitlines() for line in synopsislines: # some commands (such as rebase) have a multi-line # synopsis ui.write(" %s\n" % line) ui.write('\n') # description ui.write("%s\n\n" % d['desc'][1]) # options opt_output = list(d['opts']) if opt_output: opts_len = max([len(line[0]) for line in opt_output]) ui.write(_("Options:\n\n")) multioccur = False for optstr, desc in opt_output: if desc: s = "%-*s %s" % (opts_len, optstr, desc) else: s = optstr ui.write("%s\n" % s) if optstr.endswith("[+]>"): multioccur = True if multioccur: ui.write(_("\n[+] marked option can be specified" " multiple times\n")) ui.write("\n") # aliases if d['aliases']: ui.write(_(" aliases: %s\n\n") % " ".join(d['aliases'])) def allextensionnames(): return extensions.enabled().keys() + extensions.disabled().keys() if __name__ == "__main__": doc = 'hg.1.gendoc' if len(sys.argv) > 1: doc = sys.argv[1] ui = uimod.ui.load() if doc == 'hg.1.gendoc': showdoc(ui) else: showtopic(ui, sys.argv[1])