Mercurial > hg-stable
comparison hgext/logtoprocess.py @ 28901:a368da441b32
logtoprocess: new experimental extension
This extension lets you direct specific ui.log() information to shell
commands, spawned in the background. This can be used to, say, capture
timings, commandfailure tracebacks, etc., making the output available
to other command-line tools.
author | Martijn Pieters <mjpieters@fb.com> |
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date | Tue, 05 Apr 2016 17:39:59 +0100 |
parents | |
children | 4cf0542dcbe7 |
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28900:b65966f50058 | 28901:a368da441b32 |
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1 # logtoprocess.py - send ui.log() data to a subprocess | |
2 # | |
3 # Copyright 2016 Facebook, Inc. | |
4 # | |
5 # This software may be used and distributed according to the terms of the | |
6 # GNU General Public License version 2 or any later version. | |
7 """Send ui.log() data to a subprocess (EXPERIMENTAL) | |
8 | |
9 This extension lets you specify a shell command per ui.log() event, | |
10 sending all remaining arguments to as environment variables to that command. | |
11 | |
12 Each positional argument to the method results in a `MSG[N]` key in the | |
13 environment, starting at 1 (so `MSG1`, `MSG2`, etc.). Each keyword argument | |
14 is set as a `OPT_UPPERCASE_KEY` variable (so the key is uppercased, and | |
15 prefixed with `OPT_`). The original event name is passed in the `EVENT` | |
16 environment variable, and the process ID of mercurial is given in `HGPID`. | |
17 | |
18 So given a call `ui.log('foo', 'bar', 'baz', spam='eggs'), a script configured | |
19 for the `foo` event can expect an environment with `MSG1=bar`, `MSG2=baz`, and | |
20 `OPT_SPAM=eggs`. | |
21 | |
22 Scripts are configured in the `[logtoprocess]` section, each key an event name. | |
23 For example:: | |
24 | |
25 [logtoprocess] | |
26 commandexception = echo "$MSG2$MSG3" > /var/log/mercurial_exceptions.log | |
27 | |
28 would log the warning message and traceback of any failed command dispatch. | |
29 | |
30 Scripts are run asychronously as detached daemon processes; mercurial will | |
31 not ensure that they exit cleanly. | |
32 | |
33 """ | |
34 | |
35 from __future__ import absolute_import | |
36 | |
37 import itertools | |
38 import os | |
39 import platform | |
40 import subprocess | |
41 import sys | |
42 | |
43 # Note for extension authors: ONLY specify testedwith = 'internal' for | |
44 # extensions which SHIP WITH MERCURIAL. Non-mainline extensions should | |
45 # be specifying the version(s) of Mercurial they are tested with, or | |
46 # leave the attribute unspecified. | |
47 testedwith = 'internal' | |
48 | |
49 def uisetup(ui): | |
50 if platform.system() == 'Windows': | |
51 # no fork on Windows, but we can create a detached process | |
52 # https://msdn.microsoft.com/en-us/library/windows/desktop/ms684863.aspx | |
53 # No stdlib constant exists for this value | |
54 DETACHED_PROCESS = 0x00000008 | |
55 _creationflags = DETACHED_PROCESS | subprocess.CREATE_NEW_PROCESS_GROUP | |
56 | |
57 def runshellcommand(script, env): | |
58 # we can't use close_fds *and* redirect stdin. I'm not sure that we | |
59 # need to because the detached process has no console connection. | |
60 subprocess.Popen( | |
61 script, shell=True, env=env, close_fds=True, | |
62 creationflags=_creationflags) | |
63 else: | |
64 def runshellcommand(script, env): | |
65 # double-fork to completely detach from the parent process | |
66 # based on http://code.activestate.com/recipes/278731 | |
67 pid = os.fork() | |
68 if pid: | |
69 # parent | |
70 return | |
71 # subprocess.Popen() forks again, all we need to add is | |
72 # flag the new process as a new session. | |
73 if sys.version_info < (3, 2): | |
74 newsession = {'preexec_fn': os.setsid} | |
75 else: | |
76 newsession = {'start_new_session': True} | |
77 try: | |
78 # connect stdin to devnull to make sure the subprocess can't | |
79 # muck up that stream for mercurial. | |
80 subprocess.Popen( | |
81 script, shell=True, stdin=open(os.devnull, 'r'), env=env, | |
82 close_fds=True, **newsession) | |
83 finally: | |
84 # mission accomplished, this child needs to exit and not | |
85 # continue the hg process here. | |
86 os._exit(0) | |
87 | |
88 class logtoprocessui(ui.__class__): | |
89 def log(self, event, *msg, **opts): | |
90 """Map log events to external commands | |
91 | |
92 Arguments are passed on as environment variables. | |
93 | |
94 """ | |
95 script = ui.config('logtoprocess', event) | |
96 if script: | |
97 if msg: | |
98 # try to format the log message given the remaining | |
99 # arguments | |
100 try: | |
101 # Python string formatting with % either uses a | |
102 # dictionary *or* tuple, but not both. If we have | |
103 # keyword options, assume we need a mapping. | |
104 formatted = msg[0] % (opts or msg[1:]) | |
105 except (TypeError, KeyError): | |
106 # Failed to apply the arguments, ignore | |
107 formatted = msg[0] | |
108 messages = (formatted,) + msg[1:] | |
109 else: | |
110 messages = msg | |
111 # positional arguments are listed as MSG[N] keys in the | |
112 # environment | |
113 msgpairs = ( | |
114 ('MSG{0:d}'.format(i), str(m)) | |
115 for i, m in enumerate(messages, 1)) | |
116 # keyword arguments get prefixed with OPT_ and uppercased | |
117 optpairs = ( | |
118 ('OPT_{0}'.format(key.upper()), str(value)) | |
119 for key, value in opts.iteritems()) | |
120 env = dict(itertools.chain(os.environ.items(), | |
121 msgpairs, optpairs), | |
122 EVENT=event, HGPID=str(os.getpid())) | |
123 # Connect stdin to /dev/null to prevent child processes messing | |
124 # with mercurial's stdin. | |
125 runshellcommand(script, env) | |
126 return super(logtoprocessui, self).log(event, *msg, **opts) | |
127 | |
128 # Replace the class for this instance and all clones created from it: | |
129 ui.__class__ = logtoprocessui |