feat: [WIP] contribute tower-otel-http-metrics middleware crate

[francoposa]

Changes

This contribution is a work in progress, just wanted to get it kicked off to have eyes on it.
I was invited to contribute this by @cijothomas, and have received approval from Grafana to contribute work hours towards maintaining this.

Currently the source code lives at https://github.com/francoposa/tower-otel-http-metrics and the crate is at https://crates.io/crates/tower-otel-http-metrics.

There are some various cleanup tasks here - any advice or direction is appreciated!

• Fixing up the Cargo.toml metadata
• Moving examples into the common example directory? This might be a bit awkward given the current structure.
• Code ownership - I am not yet a member of the OpenTelemetry organization as is a requirement for other other contrib repos
• Change license - it is currently MIT, I am not sure on the specifics of how change it to Apache 2.0 works
• Changelog, need to get it from the release notes of the current repo
• ...?

Merge requirement checklist

• CONTRIBUTING guidelines followed
• Unit tests added/updated (if applicable)
• Appropriate CHANGELOG.md files updated for non-trivial, user-facing changes
• Changes in public API reviewed (if applicable)

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 155 lines in your changes missing coverage. Please review.

Project coverage is 49.4%. Comparing base (e8a88d9) to head (ea81d0b).

Files with missing lines	Patch %	Lines
opentelemetry-instrumentation-tower/src/lib.rs	0.0%	155 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##            main    #248     +/-   ##
=======================================
- Coverage   50.4%   49.4%   -1.1%     
=======================================
  Files         60      61      +1     
  Lines       7629    7784    +155     
=======================================
  Hits        3851    3851             
- Misses      3778    3933    +155     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[lalitb]

Code ownership - I am not yet a member of the OpenTelemetry organization as is a requirement for other other contrib repos
Change license - it is currently MIT, I am not sure on the specifics of how change it to Apache 2.0 works

I believe above two would be pre-requisite for this PR, rest can be discussed and handled in subsequent PRs. The MIT license is compatible with Apache 2.0, so changing the license should be fine, while keeping the attributing to original:

• Include the MIT license attribution and copyright notice for the original MIT-licensed code. This can be done in a separate NOTICE file in the root of this component.

This project includes components originally licensed under the MIT License:
Copyright (c) [Year] [Original Author Name]

[Include the full text of the MIT license here if necessary for clarity]

• The LICENSE file in the root of this component should contain the full text of the Apache 2.0 license, as this will be the primary license for the repository.

Also, if there are any questions specific to license/copyright. more clarity can be obtained by raising the question as issue in the opentelemetry/community repo.

[cijothomas]

https://github.com/open-telemetry/opentelemetry-rust-contrib/tree/main/opentelemetry-instrumentation-actix-web Consider following structure from this, for examples etc.

[cijothomas]

• license attribution and copyright notice for the original MIT-licensed code. This can be done in a separate NOTICE file in the root of this component.

Could this be considered as normal code contribution? Or this is to be treated as a code-donation? @lalitb do you know ?

[francoposa]

LICENSE and NOTICE updated in the form @lalitb suggested.
Package name updated (not sure how this would affect the current crate listing?), and references to the original github repo have been converted.

@cijothomas Re:

https://github.com/open-telemetry/opentelemetry-rust-contrib/tree/main/opentelemetry-instrumentation-actix-web Consider following structure from this

I don't see much structure to follow there considering how much more is in the examples for this package - what I have for examples is a much larger and comprehensive superset of what's in the actix-web directory.

[cijothomas]

for instrumentation's docs, it's easy to use the stdout exporter. It'll be hard to maintain proper OTLP example for each instrumentations.

[cijothomas]

can you add a readme.md file to the development folder explaining how to leverage the docker-compose, and the grafana dashboards?

I am also not sure how much detailed example we want to maintain per instrumentation. it may makes sense to move some of these to common examples, as they are applicable to any web apps...