view contrib/debugcmdserver.py @ 36067:caca3ac2ac04

wireproto: use maybecapturestdio() for push responses (API)

The "pushres" and "pusherr" response types currently call
proto.restore() in the HTTP protocol. This completes the pairing
with proto.redirect() that occurs in the @wireprotocommand
functions. (But since the SSH protocol has a no-op redirect(),
it doesn't bother calling restore() because it would also be
a no-op.)

Having the disconnect between these paired calls is very confusing.
Knowing that you must use proto.redirect() if returning a "pushres"
or a "pusherr" is even wonkier.

We replace this confusing code with our new context manager for
[maybe] capturing output.

The "pushres" and "pusherr" types have gained an "output" argument
to their constructor and an attribute to hold captured data. The
HTTP protocol now retrieves output from these objects.

.. api::

   ``wireproto.pushres`` and ``wireproto.pusherr`` now explicitly
   track stdio output.

Differential Revision: https://phab.mercurial-scm.org/D2082

#!/usr/bin/env python
#
# Dumps output generated by Mercurial's command server in a formatted style to a
# given file or stderr if '-' is specified. Output is also written in its raw
# format to stdout.
#
# $ ./hg serve --cmds pipe | ./contrib/debugcmdserver.py -
# o, 52   -> 'capabilities: getencoding runcommand\nencoding: UTF-8'

from __future__ import absolute_import, print_function
import struct
import sys

if len(sys.argv) != 2:
    print('usage: debugcmdserver.py FILE')
    sys.exit(1)

outputfmt = '>cI'
outputfmtsize = struct.calcsize(outputfmt)

if sys.argv[1] == '-':
    log = sys.stderr
else:
    log = open(sys.argv[1], 'a')

def read(size):
    data = sys.stdin.read(size)
    if not data:
        raise EOFError
    sys.stdout.write(data)
    sys.stdout.flush()
    return data

try:
    while True:
        header = read(outputfmtsize)
        channel, length = struct.unpack(outputfmt, header)
        log.write('%s, %-4d' % (channel, length))
        if channel in 'IL':
            log.write(' -> waiting for input\n')
        else:
            data = read(length)
            log.write(' -> %r\n' % data)
        log.flush()
except EOFError:
    pass
finally:
    if log != sys.stderr:
        log.close()