tests/fsmonitor-run-tests.py

help: add internals.extensions topic

I think it's better to include the API overview in core as we now have the
internals section in our help system.

Retrieved from the wiki, and formatted as reST. Several wiki links are
removed since they are invalid in the help. The sections about example
extension are removed at all as they seemed too verbose.

https://www.mercurial-scm.org/wiki/WritingExtensions

#!/usr/bin/env python

# fsmonitor-run-tests.py - Run Mercurial tests with fsmonitor enabled
#
# Copyright 2017 Facebook, Inc.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
#
# This is a wrapper around run-tests.py that spins up an isolated instance of
# Watchman and runs the Mercurial tests against it. This ensures that the global
# version of Watchman isn't affected by anything this test does.

from __future__ import absolute_import
from __future__ import print_function

import argparse
import contextlib
import json
import os
import shutil
import subprocess
import sys
import tempfile
import uuid

osenvironb = getattr(os, 'environb', os.environ)

if sys.version_info > (3, 5, 0):
    PYTHON3 = True
    xrange = range # we use xrange in one place, and we'd rather not use range
    def _bytespath(p):
        return p.encode('utf-8')

elif sys.version_info >= (3, 0, 0):
    print('%s is only supported on Python 3.5+ and 2.7, not %s' %
          (sys.argv[0], '.'.join(str(v) for v in sys.version_info[:3])))
    sys.exit(70) # EX_SOFTWARE from `man 3 sysexit`
else:
    PYTHON3 = False

    # In python 2.x, path operations are generally done using
    # bytestrings by default, so we don't have to do any extra
    # fiddling there. We define the wrapper functions anyway just to
    # help keep code consistent between platforms.
    def _bytespath(p):
        return p

def getparser():
    """Obtain the argument parser used by the CLI."""
    parser = argparse.ArgumentParser(
        description='Run tests with fsmonitor enabled.',
        epilog='Unrecognized options are passed to run-tests.py.')
    # - keep these sorted
    # - none of these options should conflict with any in run-tests.py
    parser.add_argument('--keep-fsmonitor-tmpdir', action='store_true',
        help='keep temporary directory with fsmonitor state')
    parser.add_argument('--watchman',
        help='location of watchman binary (default: watchman in PATH)',
        default='watchman')

    return parser

@contextlib.contextmanager
def watchman(args):
    basedir = tempfile.mkdtemp(prefix='hg-fsmonitor')
    try:
        # Much of this configuration is borrowed from Watchman's test harness.
        cfgfile = os.path.join(basedir, 'config.json')
        # TODO: allow setting a config
        with open(cfgfile, 'w') as f:
            f.write(json.dumps({}))

        logfile = os.path.join(basedir, 'log')
        clilogfile = os.path.join(basedir, 'cli-log')
        if os.name == 'nt':
            sockfile = '\\\\.\\pipe\\watchman-test-%s' % uuid.uuid4().hex
        else:
            sockfile = os.path.join(basedir, 'sock')
        pidfile = os.path.join(basedir, 'pid')
        statefile = os.path.join(basedir, 'state')

        argv = [
            args.watchman,
            '--sockname', sockfile,
            '--logfile', logfile,
            '--pidfile', pidfile,
            '--statefile', statefile,
            '--foreground',
            '--log-level=2', # debug logging for watchman
        ]

        envb = osenvironb.copy()
        envb[b'WATCHMAN_CONFIG_FILE'] = _bytespath(cfgfile)
        with open(clilogfile, 'wb') as f:
            proc = subprocess.Popen(
                argv, env=envb, stdin=None, stdout=f, stderr=f)
            try:
                yield sockfile
            finally:
                proc.terminate()
                proc.kill()
    finally:
        if args.keep_fsmonitor_tmpdir:
            print('fsmonitor dir available at %s' % basedir)
        else:
            shutil.rmtree(basedir, ignore_errors=True)

def run():
    parser = getparser()
    args, runtestsargv = parser.parse_known_args()

    with watchman(args) as sockfile:
        osenvironb[b'WATCHMAN_SOCK'] = _bytespath(sockfile)
        # Indicate to hghave that we're running with fsmonitor enabled.
        osenvironb[b'HGFSMONITOR_TESTS'] = b'1'

        runtestdir = os.path.dirname(__file__)
        runtests = os.path.join(runtestdir, 'run-tests.py')
        blacklist = os.path.join(runtestdir, 'blacklists', 'fsmonitor')

        runtestsargv.insert(0, runtests)
        runtestsargv.extend([
            '--extra-config',
            'extensions.fsmonitor=',
            # specify fsmonitor.mode=paranoid always in order to force
            # fsmonitor extension execute "paranoid" code path
            #
            # TODO: make fsmonitor-run-tests.py accept specific options
            '--extra-config',
            'fsmonitor.mode=paranoid',
            '--blacklist',
            blacklist,
        ])

        return subprocess.call(runtestsargv)

if __name__ == '__main__':
    sys.exit(run())