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epsagon / epsagon-go

Automated tracing library for Go 1.x ⚡️
https://epsagon.com
MIT License
28 stars 11 forks source link

Wrapping services that use http.Client #14

Closed dsolonenko closed 3 years ago

dsolonenko commented 5 years ago

It is quite useful to automatically wrap http requests going through http.Client with epsagonhttp.Wrap. Unfortunately this does not work with official golang client for services like Heroku Platform API for example: https://github.com/heroku/heroku-go

client := epsagonhttp.Wrap(http.Client{})
service := heroku.NewService(client)

because ClientWrapper cannot be used in place of http.Client.

This looks like a weird golang design choice to make http.Client a struct instead of interface. But it would be great to explore some alternatives that would not require forking the service to accept ClientWrapper.

enoodle commented 5 years ago

Thank you for your report! I see the issue, yet I am not sure how to solve it now. It is, as you pointed out, a result of architecture flaw that started with http.Client and was adopted here.

The only alternative I can currently think of to keep using http.Client is to create some local server that will get all the calls (by changing the url to something like https://localhost:88888/<ORIGINAL_URL> ) but it will have many other issues with encoding the url, lifecycle management and using parameters. I am not keen to start exploring this, and would love to hear other suggestions.

dsolonenko commented 5 years ago

Hello @enoodle, agree, having a local http client proxy does look like an overkill :)

Another options is to provide a wrapper for the http client's transport http.RoundTripper. The traces would be less accurate, but it would be possible to use the http client as is in the third party services. This seems the approach that Stackdriver tracer is using https://cloud.google.com/trace/docs/setup/go

enoodle commented 5 years ago

Cool I will sure be taking a look into this and put it in our road map. I am a bit swamped at the moment with other things so I am not sure when exactly I will get to it.