Add prometheus metrics

[nicholasgibson2]

Replacement PR for https://github.com/Yelp/elastalert/pull/2211

[nicholasgibson2]

@andres-tw FYI

[kannanvr]

Hi All, When the metrics part will be available to use. We are all eagerly awiting for this PR to get merge... Please do the needful

[Shashankft9]

Just mentioning this here as well: https://github.com/abhishekjiitr/elastalert/pull/1#issuecomment-582265932

[nicholasgibson2]

Can someone assist me with the build issues?

[abhishek-jaisingh]

@nicholasgibson2 the code seems to be running fine, flake8 is exiting with NZEC because of some code-style errors:

./elastalert/prometheus_wrapper.py:3:1: E302 expected 2 blank lines, found 1

./elastalert/prometheus_wrapper.py:15:26: E221 multiple spaces before operator

./elastalert/prometheus_wrapper.py:16:23: E221 multiple spaces before operator

./elastalert/prometheus_wrapper.py:17:26: E221 multiple spaces before operator

./elastalert/prometheus_wrapper.py:18:29: E221 multiple spaces before operator

./elastalert/prometheus_wrapper.py:19:30: E221 multiple spaces before operator

./elastalert/prometheus_wrapper.py:20:141: E501 line too long (144 > 140 characters)

./elastalert/prometheus_wrapper.py:21:25: E221 multiple spaces before operator

./elastalert/prometheus_wrapper.py:22:141: E501 line too long (144 > 140 characters)

./elastalert/elastalert.py:58:1: E302 expected 2 blank lines, found 1

./elastalert/elastalert.py:108:141: E501 line too long (145 > 140 characters)

./elastalert/elastalert.py:2055:9: F841 local variable 'p' is assigned to but never used

Check detailed log here: https://travis-ci.org/Yelp/elastalert/jobs/648613367?utm_medium=notification&utm_source=github_status

[nicholasgibson2]

Alright fixed the build issues

[andres-tw]

@nicholasgibson2 have you thought about submitting this PR to https://github.com/jertel/elastalert ?

[nicholasgibson2]

@andres-tw I'll check it out!