Comment 9 for bug 1655182

Reviewed: https://review.openstack.org/466873
Committed: https://git.openstack.org/cgit/openstack/keystone/commit/?id=8726573940c435ec75ca72a9ec20d9744561c07c
Submitter: Jenkins
Branch: stable/newton

commit 8726573940c435ec75ca72a9ec20d9744561c07c
Author: John Dennis <email address hidden>
Date: Tue Nov 29 11:36:32 2016 -0500

    Fix keystone-manage mapping_engine tester

    There were several problems with keystone-manage mapping_engine

    * It aborts with a backtrace because of wrong number of arguments
      passed to the RuleProcessor, it was missing the mapping_id
      parameter.

    * Error messages related to input data were cryptic and inprecise.

    * The --engine-debug option did not work.

    A fake mapping_id is now generated and passed to the RuleProcessor.

    If there was invalid data passed it was nearly impossible to determine
    what was causing the error, the command takes 2 input files, but which
    file contained the error? At what line? Why? For example I was
    consistently getting this error:

    Error while parsing line: '{': need more than 1 value to unpack

    and had no idea of what was wrong, the JSON looked valid to me. Turns
    out the assertion file is not formatted as JSON (yes this is
    documented in the help message but given the rules are JSON formatted
    and the RuleProcessor expects a dict for the assertion_data it's
    reasonsable to assume the data in the assertion file is formatted as a
    JSON object).

    The documentation in mapping_combinations.rst added a note in the
    section suggesting the use of the keystone-manage mapping_engine
    tester alerting the reader to the expected file formats.

    The MappingEngineTester class was refactored slighly to allow each
    method to know what file it was operating on and emit error messages
    that identify the file. The error message in addition to the pathname
    now includes the offending line number as well. As a bonus it doesn't
    fail if there is a blank line. The error message now looks like this:

    assertion file input.txt at line 4 expected 'key: value' but found 'foo' see help for file format

    The mapping_engine.LOG.logger level is now explictily set to DEBUG
    when --engine-debug is passed instead of (mistakenly assuming it
    defaulted to DEBUG) otherwise it's set to WARN.

    Closes-Bug: 1655182
    Signed-off-by: John Dennis <email address hidden>
    Change-Id: I2dea0f38b127ec185b79bfe06dd6a212da75cbca
    (cherry picked from commit f2d0f8c9ab38172a6e37b02339eac59da911435c)