[graal] Add support of Graal's CoLic Backend to ELK [File-level + Study] (WIP)

[inishchith]

Address: inishchith/gsoc#9

TODO:

• Add tests
• Update docstrings
• Update commit description

NOTE:

• The failing test is due to Graal module not being a part of requirements.txt(dependencies) and is a part of this PR just to check the coverage of new additions.

Signed-off-by: inishchith inishchith@gmail.com

[coveralls]

Pull Request Test Coverage Report for Build 1581

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 52 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.2%) to 68.088%

---

Files with Coverage Reduction	New Missed Lines	%
/home/travis/build/chaoss/grimoirelab-elk/grimoire_elk/utils.py	52	60.56%

Totals
Change from base Build 1573:	-0.2%
Covered Lines:	5748
Relevant Lines:	8442

---

💛 - Coveralls

[valeriocos]

Thank you @inishchith for the PR. Overall it looks OK. I see that some code of the study is similar to the one proposed here: #664. It would be possible to abstract the common logic to a class (e.g., study_evolution) and call it from cocom and colic enrichers?

A similar comment targets the file graal_utils, it would be possible to wrap the variables in graal_utils to methods, which use some variables to set up the query attributes? If this is possible, then we could include these methods in the study_evolution file.

WDYT?

[inishchith]

@valeriocos Yes. Agree with your thoughts. Will update the PR once I've worked on it.

Thanks!

[valeriocos]

Thank you @inishchith! Also this PR looks great. The comments are similar to the PR #664, plus there are some suggestions to reduce redundant code. Let me know what you think.

[valeriocos]

Thanks @inishchith to address my comments. Overall the PR looks great.
I'm not sure whether it's better to unify this PR with #664, since there are common pieces of code, and some modifications cannot be done. WDYT?

[inishchith]

Thanks for the review @valeriocos.
I was thinking to open a new PR(and close these by referencing them in the newer one) by the following levels of commit:

1. Requirements
2. CoCom Integration
3. CoLic Integration
4. Segregating common parts out
5. Tests

Which would allow us to focus on Graal integrations as a whole and testing would become much easier.
Let me know what you think :)

[valeriocos]

You're welcome @inishchith and thanks for proposing the levels of commit :)

I would add a 6. point to add the csvs of the colic and cocom (as reference you can have a look at the git.csv)

[inishchith]

closing in reference to #672