opentelemetry-go-contrib VS opentelemetry-specificatio

While many programming languages provide robust support for Open Telemetry, this instance focuses on Golang. It's important to note that, in the current context, the logs SDK for Golang is not implemented. For future reference consult the list of supported languages and explore the Open Telemetry repositories. Always prioritize the main repository and its contrib repository, housing extensions and instrumentation libraries crucial to the Open Telemetry framework. Stay updated with the latest developments to ensure seamless integration and enhanced functionality.

It’s assumed that the instrumentation of each component has been completed, and the HTTP communication has also been instrumented by net/http auto instrumentation library.

Tracing, including context propagation, is easy to set up with REST or gRPC. You can instrument most important parts of your application with the contrib package. Some libraries like go-redis have their own otel features, which could be a promising trend in the future. There are some important gaps though; for example, you'll have to go third party for database/sql.

I see! Yeah, this is one where where otel-go is a lot harder to use, but it's something the SIG is looking at. A coworker of mine is helping drive a design that's sort of an "easy button" to configure all the things with the least-surprising defaults[0] and we're seeing how people like it in our SDK distribution that uses it[1]. I hope that sometime soon we'll have the design polished-up enough to get merged in. Like most OSS projects, it'll take some time but I'm confident we can get it done.

The main challenge is that there's a large variety of use cases to fulfill (e.g., someone wants custom context propagation, a custom span processor, and export over HTTP+json but not HTTP+protobuf) and today the answer to that is that you have to pull in all the libraries for all the things you need. It's a lot more energy you need to expend to get started with all of this than it needs to be.

As for logging support in the Go SDK, it's frozen mostly just due to lack of bandwidth and a need to finish what's already been started. Metrics have proven to be much more difficult and time-consuming to implement correctly across all languages, with Go being impacted harder than other languages (e.g., Python and .NET). I think you can expect logging integrations in the near-ish future though.

This is great feedback. I'll pass it on folks who haven't seen it. Thank you! And please feel free to file issues about all the things that rub you the wrong way

[0]: https://github.com/open-telemetry/opentelemetry-go-contrib/p...

[1]: https://github.com/honeycombio/honeycomb-opentelemetry-go

OpenTelemetry middleware for Gin

OpenTelemetry is the work-in-progress merge of OpenCensus and OpenTracing. It is still in early stages as of 2021. We are using its instrumentation libraries opentelemetry-go and [opentelemetry-go-contrib]https://github.com/open-telemetry/opentelemetry-go-contrib/) for our Go services.

Usually the span propagation is located in headers Here you can see an example https://github.com/open-telemetry/opentelemetry-go-contrib/blob/main/instrumentation/github.com/gin-gonic/gin/otelgin/gintrace.go

OpenTelemetry has specific instrumentation packages to support popular Golang packages and use cases. For example, this app uses the Gin framework for request routing. OpenTelemetry provides instrumentation package named otelgin to instrument the Gin framework which you need to import in your app. You can find the complete list of supported Golang packages by OpenTelemetry here.

Hi u/brofesor, Your understanding is correct. Though the library you mentioned is not official. I found an issue in the official repo regarding this https://github.com/open-telemetry/opentelemetry-go-contrib/issues/714

Here I described all my experiments: https://github.com/open-telemetry/opentelemetry-go-contrib/issues/746

Sure, happy to provide more specifics!

Our main issue was the lack of a synchronous gauge. The officially supported asynchronous API of registering a callback function to report a gauge metric is very different from how we were doing things before, and would have required lots of refactoring of our code. Instead, we wrote a wrapper that exposes a synchronous-like API: https://gist.github.com/yolken-airplane/027867b753840f7d15d6....

It seems like this is a common feature request across many of the SDKs, and it's in the process of being fixed in some of them (https://github.com/open-telemetry/opentelemetry-specificatio...)? I'm not sure what the plans are for the golang SDK specifically.

Another, more minor issue, is the lack of support for "constant" attributes that are applied to all metrics. We use these to identify the app, among other use cases, so we added wrappers around the various "Add", "Record", "Observe", etc. calls that automatically add these. (It's totally possible that this is supported and I missed it, in which case please let me know!).

Overall, the SDK was generally well-written and well-documented, we just needed some extra work to make the interfaces more similar to the ones were were using before.

Two problems with OpenTelemetry:

1. It doesn't know what the hell it is. Is it a semantic standard? Is a protocol? It is a facade? What layer of abstraction does it provide? Answer: All of the above! All the things! All the layers!

2. No one from OpenTelemetry has actually tried instrumenting a library. And if they have, they haven't the first suggestion on how instrumenters should actually use metrics, traces, and logs. Do you write to all three? To one? I asked this question two years ago, not a single response. [1]

[1] https://github.com/open-telemetry/opentelemetry-specificatio...

That's why you have otel logging: https://github.com/open-telemetry/opentelemetry-specificatio...

There are a large amount of subtle tradeoffs around the bucketing scheme (log, vs. log-linear, base) and memory layout (sparse, dense, chunked) the amount of configurability in the histogram space (circllhist, DDSketch, HDRHistogram, ...). A good overview is this discussion here:

https://github.com/open-telemetry/opentelemetry-specificatio...

As for the circllhist: There are no knobs to turn. It uses base 10 and two decimal digits of precision. In the last 8 years I have not seen a single use-case in the operational domain where this was not appropriate.

A good place to look at is the milestones on GitHub: https://github.com/open-telemetry/opentelemetry-specificatio...

Logging is still experimental in the spec. Metrics API is feature freeze and the protocol is stable, so it's more on language SDKs to stabilize their implementations. This is a focus for several of them right now.