Mercurial > hg
view mercurial/hook.py @ 29847:9a9629b9416c stable
bundle2: fail faster when interrupted
Before this patch, bundle2 application attempted to consume remaining
bundle2 part data when the process is interrupted (SIGINT) or when
sys.exit is called (translated into a SystemExit exception). This
meant that if one of these occurred when applying a say 1 GB
changegroup bundle2 part being downloaded over a network, it may take
Mercurial *several minutes* to terminate after a SIGINT because the
process is waiting on the network to stream megabytes of data. This is
not a great user experience and a regression from bundle1. Furthermore,
many process supervisors tend to only give processes a finite amount of
time to exit after delivering SIGINT: if processes take too long to
self-terminate, a SIGKILL is issued and Mercurial has no opportunity to
clean up. This would mean orphaned locks and transactions. Not good.
This patch changes the bundle2 application behavior to fail faster
when an interrupt or system exit is requested. It does so by not
catching BaseException (which includes KeyboardInterrupt and
SystemExit) and by explicitly checking for these conditions in
yet another handler which would also seek to the end of the current
bundle2 part on failure.
The end result of this patch is that SIGINT is now reacted to
significantly faster: the active transaction is rolled back
immediately without waiting for incoming bundle2 data to be consumed.
This restores the pre-bundle2 behavior and makes Mercurial treat
signals with the urgency they deserve.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Thu, 25 Aug 2016 19:53:14 -0700 |
parents | ea1fec3e9aba |
children | a1259e502bdf |
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# hook.py - hook support for mercurial # # Copyright 2007 Matt Mackall <mpm@selenic.com> # # 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 import os import sys import time from .i18n import _ from . import ( demandimport, error, extensions, util, ) def _pythonhook(ui, repo, name, hname, funcname, args, throw): '''call python hook. hook is callable object, looked up as name in python module. if callable returns "true", hook fails, else passes. if hook raises exception, treated as hook failure. exception propagates if throw is "true". reason for "true" meaning "hook failed" is so that unmodified commands (e.g. mercurial.commands.update) can be run as hooks without wrappers to convert return values.''' if callable(funcname): obj = funcname funcname = obj.__module__ + "." + obj.__name__ else: d = funcname.rfind('.') if d == -1: raise error.HookLoadError( _('%s hook is invalid: "%s" not in a module') % (hname, funcname)) modname = funcname[:d] oldpaths = sys.path if util.mainfrozen(): # binary installs require sys.path manipulation modpath, modfile = os.path.split(modname) if modpath and modfile: sys.path = sys.path[:] + [modpath] modname = modfile with demandimport.deactivated(): try: obj = __import__(modname) except (ImportError, SyntaxError): e1 = sys.exc_info() try: # extensions are loaded with hgext_ prefix obj = __import__("hgext_%s" % modname) except (ImportError, SyntaxError): e2 = sys.exc_info() if ui.tracebackflag: ui.warn(_('exception from first failed import ' 'attempt:\n')) ui.traceback(e1) if ui.tracebackflag: ui.warn(_('exception from second failed import ' 'attempt:\n')) ui.traceback(e2) if not ui.tracebackflag: tracebackhint = _( 'run with --traceback for stack trace') else: tracebackhint = None raise error.HookLoadError( _('%s hook is invalid: import of "%s" failed') % (hname, modname), hint=tracebackhint) sys.path = oldpaths try: for p in funcname.split('.')[1:]: obj = getattr(obj, p) except AttributeError: raise error.HookLoadError( _('%s hook is invalid: "%s" is not defined') % (hname, funcname)) if not callable(obj): raise error.HookLoadError( _('%s hook is invalid: "%s" is not callable') % (hname, funcname)) ui.note(_("calling hook %s: %s\n") % (hname, funcname)) starttime = time.time() try: # redirect IO descriptors to the ui descriptors so hooks # that write directly to these don't mess up the command # protocol when running through the command server old = sys.stdout, sys.stderr, sys.stdin sys.stdout, sys.stderr, sys.stdin = ui.fout, ui.ferr, ui.fin r = obj(ui=ui, repo=repo, hooktype=name, **args) except Exception as exc: if isinstance(exc, error.Abort): ui.warn(_('error: %s hook failed: %s\n') % (hname, exc.args[0])) else: ui.warn(_('error: %s hook raised an exception: ' '%s\n') % (hname, exc)) if throw: raise if not ui.tracebackflag: ui.warn(_('(run with --traceback for stack trace)\n')) ui.traceback() return True, True finally: sys.stdout, sys.stderr, sys.stdin = old duration = time.time() - starttime ui.log('pythonhook', 'pythonhook-%s: %s finished in %0.2f seconds\n', name, funcname, duration) if r: if throw: raise error.HookAbort(_('%s hook failed') % hname) ui.warn(_('warning: %s hook failed\n') % hname) return r, False def _exthook(ui, repo, name, cmd, args, throw): ui.note(_("running hook %s: %s\n") % (name, cmd)) starttime = time.time() env = {} # make in-memory changes visible to external process if repo is not None: tr = repo.currenttransaction() repo.dirstate.write(tr) if tr and tr.writepending(): env['HG_PENDING'] = repo.root for k, v in args.iteritems(): if callable(v): v = v() if isinstance(v, dict): # make the dictionary element order stable across Python # implementations v = ('{' + ', '.join('%r: %r' % i for i in sorted(v.iteritems())) + '}') env['HG_' + k.upper()] = v if repo: cwd = repo.root else: cwd = os.getcwd() r = ui.system(cmd, environ=env, cwd=cwd) duration = time.time() - starttime ui.log('exthook', 'exthook-%s: %s finished in %0.2f seconds\n', name, cmd, duration) if r: desc, r = util.explainexit(r) if throw: raise error.HookAbort(_('%s hook %s') % (name, desc)) ui.warn(_('warning: %s hook %s\n') % (name, desc)) return r # represent an untrusted hook command _fromuntrusted = object() def _allhooks(ui): """return a list of (hook-id, cmd) pairs sorted by priority""" hooks = _hookitems(ui) # Be careful in this section, propagating the real commands from untrusted # sources would create a security vulnerability, make sure anything altered # in that section uses "_fromuntrusted" as its command. untrustedhooks = _hookitems(ui, _untrusted=True) for name, value in untrustedhooks.items(): trustedvalue = hooks.get(name, (None, None, name, _fromuntrusted)) if value != trustedvalue: (lp, lo, lk, lv) = trustedvalue hooks[name] = (lp, lo, lk, _fromuntrusted) # (end of the security sensitive section) return [(k, v) for p, o, k, v in sorted(hooks.values())] def _hookitems(ui, _untrusted=False): """return all hooks items ready to be sorted""" hooks = {} for name, cmd in ui.configitems('hooks', untrusted=_untrusted): if not name.startswith('priority'): priority = ui.configint('hooks', 'priority.%s' % name, 0) hooks[name] = (-priority, len(hooks), name, cmd) return hooks _redirect = False def redirect(state): global _redirect _redirect = state def hook(ui, repo, name, throw=False, **args): if not ui.callhooks: return False hooks = [] for hname, cmd in _allhooks(ui): if hname.split('.')[0] == name and cmd: hooks.append((hname, cmd)) res = runhooks(ui, repo, name, hooks, throw=throw, **args) r = False for hname, cmd in hooks: r = res[hname][0] or r return r def runhooks(ui, repo, name, hooks, throw=False, **args): res = {} oldstdout = -1 try: for hname, cmd in hooks: if oldstdout == -1 and _redirect: try: stdoutno = sys.__stdout__.fileno() stderrno = sys.__stderr__.fileno() # temporarily redirect stdout to stderr, if possible if stdoutno >= 0 and stderrno >= 0: sys.__stdout__.flush() oldstdout = os.dup(stdoutno) os.dup2(stderrno, stdoutno) except (OSError, AttributeError): # files seem to be bogus, give up on redirecting (WSGI, etc) pass if cmd is _fromuntrusted: if throw: raise error.HookAbort( _('untrusted hook %s not executed') % name, hint = _("see 'hg help config.trusted'")) ui.warn(_('warning: untrusted hook %s not executed\n') % name) r = 1 raised = False elif callable(cmd): r, raised = _pythonhook(ui, repo, name, hname, cmd, args, throw) elif cmd.startswith('python:'): if cmd.count(':') >= 2: path, cmd = cmd[7:].rsplit(':', 1) path = util.expandpath(path) if repo: path = os.path.join(repo.root, path) try: mod = extensions.loadpath(path, 'hghook.%s' % hname) except Exception: ui.write(_("loading %s hook failed:\n") % hname) raise hookfn = getattr(mod, cmd) else: hookfn = cmd[7:].strip() r, raised = _pythonhook(ui, repo, name, hname, hookfn, args, throw) else: r = _exthook(ui, repo, hname, cmd, args, throw) raised = False res[hname] = r, raised # The stderr is fully buffered on Windows when connected to a pipe. # A forcible flush is required to make small stderr data in the # remote side available to the client immediately. sys.stderr.flush() finally: if _redirect and oldstdout >= 0: os.dup2(oldstdout, stdoutno) os.close(oldstdout) return res