view hgdemandimport/tracing.py @ 42278:8dc22a209420

automation: wait for instance profiles and roles

Otherwise there is a race condition between creating the resources
and us attempting to use them / them becoming available.

The role waiter API was recently introduced, so we had to upgrade
the boto3 package to get it. Other packages were also updated
to latest versions just because.

Even with this change, I still run into issues with the IAM instance
profile not being available when we attempt to create an EC2 instance
using a just-created profile. I'm not sure what's going on. Possibly
a bug on Amazon's end. But the new behavior is "more correct."

Differential Revision: https://phab.mercurial-scm.org/D6286

# Support code for event tracing in Mercurial. Lives in demandimport
# so it can also be used in demandimport.
#
# Copyright 2018 Google LLC.
#
# 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 contextlib
import os

_pipe = None
_checked = False

@contextlib.contextmanager
def log(whencefmt, *whenceargs):
    global _pipe, _session, _checked
    if _pipe is None:
        if _checked:
            yield
            return
        _checked = True
        if 'HGCATAPULTSERVERPIPE' not in os.environ:
            yield
            return
        _pipe = open(os.environ['HGCATAPULTSERVERPIPE'], 'w', 1)
        _session = os.environ.get('HGCATAPULTSESSION', 'none')
    whence = whencefmt % whenceargs
    try:
        # Both writes to the pipe are wrapped in try/except to ignore
        # errors, as we can see mysterious errors in here if the pager
        # is active. Presumably other conditions could trigger
        # problems too.
        try:
            _pipe.write('START %s %s\n' % (_session, whence))
        except IOError:
            pass
        yield
    finally:
        try:
            _pipe.write('END %s %s\n' % (_session, whence))
        except IOError:
            pass