config_template fails to parse template if it contains a comment with leading spaces

[Mohammed Naser]

If you use config_template with a template which contains leading spaces in a comment before the first section, for example

"""
  # foo
[DEFAULT]
foo=bar
"""

The above will fail to parse because of the spaces, however, the following should work:

"""
# foo
[DEFAULT]
foo=bar
"""

config_template should be able to gracefully handle these cases, though, it seems that the issue stems from ConfigParser not liking that behaviour.

[Sam Choraria (samc-bbc)]

In trying to address this bug we found that Pythons ConfigParser
module will not parse an input file with an indented comment line
with leading whitespace before the first section header.

We added a valid test case to `test_with_comments.ini`
which could be loaded by the ansible-config_template
module with minor changes, but subsequent ini lookup
tests fail due to Pythons ConfigParser.

We think allowing ansible-config_template to parse files
with indented comment lines with leading whitespace will cause
ansible ini lookups to fail.

>>> import ConfigParser, os
>>> config = ConfigParser.ConfigParser()
>>> config.readfp(open('/tmp/test_with_comments.ini'))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.7/ConfigParser.py", line 324, in readfp
    self._read(fp, filename)
  File "/usr/lib/python2.7/ConfigParser.py", line 512, in _read
    raise MissingSectionHeaderError(fpname, lineno, line)
ConfigParser.MissingSectionHeaderError: File contains no section headers.
file: /tmp/test_with_comments.ini, line: 1

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.openstack.org/636935

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/rocky
Review: https://review.openstack.org/637495

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/636935
Committed: https://git.openstack.org/cgit/openstack/ansible-config_template/commit/?id=66a97f2b403252d2b6f8aaa38f17deccbd753b4c
Submitter: Zuul
Branch: master

commit 66a97f2b403252d2b6f8aaa38f17deccbd753b4c
Author: Georgina Shippey <email address hidden>
Date: Thu Feb 14 11:50:50 2019 +0000

    Remove whitespace before comments

    Python 2.7 ConfigParser does not accept whitespace before comments.
    To keep config files produced by ansible-config_temple parsable
    we will strip out the whitespace preceding comments.

    Change-Id: I39c88578d0a9e42fded7410d7eb4ec8bd415550c
    Related-Bug: #1755821

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/637495
Committed: https://git.openstack.org/cgit/openstack/openstack-ansible-plugins/commit/?id=43d2ef6a000c44da3358e2dd0d7c04db68c9b1a9
Submitter: Zuul
Branch: stable/rocky

commit 43d2ef6a000c44da3358e2dd0d7c04db68c9b1a9
Author: Georgina Shippey <email address hidden>
Date: Mon Feb 18 08:54:38 2019 +0000

    Remove whitespace before comments

    Python 2.7 ConfigParser does not accept whitespace before comments.
    To keep config files produced by ansible-config_temple parsable
    we will strip out the whitespace preceding comments.

    Change-Id: Ie1236c4c44dc39c7172b7a02afe9c35d92ee9e0a
    Closes-Bug: #1755821

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/openstack-ansible-plugins rocky-eol release.