OpenTelemetry Collector Ecosystem Integration

[Nicolas-MacBeth]

This PR is meant to define the folder and introduce the community to the receiver I've been working on, and get feedback on it. It includes a README with the current state of the config which is also a really good in-depth config explanation.

Hi! I'm Nic, an intern @ Google.

prometheus_exec is a receiver meant to make it easy for users to get up-and-running quickly, collecting metrics from their favorite third-party services (that don't normally support instrumentation). This frictionless experience should help with adoption and be an attractive solution for those holding out on using the Collector because their systems/services were not compatible. In a nutshell, it runs binaries of Prometheus exporters (custom-built code that make third-party services, such as MySQL, Redis, etc. communicate the Prometheus protocol) and spawns the equivalent Prometheus receiver to collect the metrics. It handles crashing binaries by applying exponential backoff, can assign a random port and supports string templating. Please read the README (it really has a lot of useful info) or ask me for more details :) !

README link with markdown applied (much nicer read): link

For example, a user wants to quickly get metrics from their MySQL and Apache servers running on a VM. Simply, they indicate a couple of things in the configuration file, download the exporter binaries and run the Collector. It will handle starting the exporters, starting the equivalent receivers and making everything work like magic (hopefully).

Example configuration:

receivers:
    prometheus_exec/apache:
        exec: ./apache_exporter --retry=false
        port: 1234 
        scrape_interval: 60s

    prometheus_exec/postgresql:
        exec: ./postgresql_exporter --port {{port}} --config conf.xml
        port: 9876
        env:
          - name: DATA_SOURCE_NAME
            value: user:password@url:port/dbname

[codecov]

Codecov Report

Merging #370 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #370   +/-   ##
=======================================
  Coverage   82.59%   82.59%           
=======================================
  Files         170      170           
  Lines        9063     9063           
=======================================
  Hits         7486     7486           
  Misses       1251     1251           
  Partials      326      326           

Flag	Coverage Δ
#integration	0.00% <ø> (ø)
#unit	82.59% <ø> (ø)

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[james-bebbington]

Left a few comments

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Side note:

README link with markdown applied (much nicer read): link

You can get to the raw file from the PR via:

[james-bebbington]

@Nicolas-MacBeth Close this?

[bogdandrutu]

@james-bebbington why closing? Is it no longer needed?

[Nicolas-MacBeth]

It is needed @bogdandrutu ! I had just done it for early review and tweaking of the design/README. The full PR is done and can be found here: #453. That PR was a little massive, so I've broken it into 2 chunks, first part is here: #499. As soon as the first part is merged, I'll make the second.

To recap, I'm closing this PR, have a second huge PR with the entire receiver and finally have a third PR with a chunk of it (easier to review and merge). Thanks @james-bebbington

[james-bebbington]

If this README is still up to date, we can keep this PR - it says "under development" so can be checked in before the rest of the code imo. I just noticed you had the same file committed in both PRs, and this one seems to be out of date.

[Nicolas-MacBeth]

I'll close it since the README is out of date, and to not have too many PRs open at once!