Support proxy configuration field in all exporters

[cloudnativestack]

Is your feature request related to a problem? Please describe.
We have collectors running in hosts within internal network which does not allow outgoing traffic to backends in public internet. A proxy must be used. However, currently OpenTelemetry collector only supports setting a proxy through HTTP[S]_PROXY environment variable, which is extremely unfriendly for collectors running in physical hosts. Only SREs have the privilege to start/stop/restart collectors and it's very hard to inject environment variables to these processes.

Describe the solution you'd like
I would like to field of configuration that can be explicitly set such as:

     some_exporter:
         proxy: example.com:1234

The config can be added to places like https://github.com/open-telemetry/opentelemetry-collector/tree/main/exporter/exporterhelper

Each exporter should be able have a separate proxy config and should override proxies set by environment variables.

Describe alternatives you've considered
No alternative.

Additional context
Some exporters already support proxy, such as awsxray exporter.

[hrittikhere]

@jpkrohling saw your LI post. Would love to work on this with help of your guidance if it's still available 🙌

[jpkrohling]

Absolutely, ping me on Slack, and I can help you further. But basically, I believe it's just a matter of adding a new config option here:

opentelemetry-collector/config/confighttp/confighttp.go

Line 31 in cdbe8e7

type HTTPClientSettings struct {

And then add the proxy URL to the transport around here:

opentelemetry-collector/config/confighttp/confighttp.go

Line 126 in cdbe8e7

You can probably set the Proxy attribute of the transport to this:

https://pkg.go.dev/net/http#ProxyURL

[rvyash]

Hey @jpkrohling, I’m interested in this issue. If it has been solved by @hrittikhere thats great 😊. I’m also looking for some good first issues, if you have any recommendations.

[jpkrohling]

We do have other good first issues in this repository: good first issue Good for newcomers

Feel free to choose one.

[hrittikhere]

We can close this as fixed @jpkrohling 👀

[loicdescotte]

Hi, It seems there is no documentation about this setting usage

[jpkrohling]

@loicdescotte, would you mind opening a PR, and perhaps another issue? Basically, one can set proxy_url on any exporters using the confighttp's HTTPClientSettings, like OTLP Exporter. It's to be set at the same level as the endpoint property, and follows the semantics of https://pkg.go.dev/net/http#ProxyURL

[loicdescotte]

Hi, I can't open a PR as I won't be able to test it, because I am using AWS Distro for OTEL, that is not using the same semantics for the proxy. I can't open an issue though.