otlploggrpc: Add examples with self-signed certificates

[xue20xi]

Towards #6661

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: xue20xi / name: Guilin Liang (d4c7166, 71de665, 50fbb13, c274e4c, dd29234, 35330ae, 832921d, 555ab21, 88a7c44, b27150d, a25ae82, 67eaf3c, 7b5992a)
• ✅ login: pellared / name: Robert Pająk (ac7b5c0, 63c83a4)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 82.8%. Comparing base (5da6cd2) to head (ac7b5c0).

Additional details and impacted files

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##            main   #6882   +/-   ##
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  Coverage   82.8%   82.8%           
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  Files        262     262           
  Lines      24339   24339           
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+ Hits       20153   20154    +1     
+ Misses      3811    3810    -1     
  Partials     375     375           

see 1 file with indirect coverage changes

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[xue20xi]

Hi @pellared ,
I just pushed a new commit to address your comments, could you review again?

[pellared]

This PR seems improperly synced with main.

[pellared]

I like this. I just added some cleanup comments. Hopefully these are my last comments 😉

Do you want to make similar PRs for other OTLP exporters (otlploghttp, otlpmetricgrpc, otlpmetrichttp, otlptracegrpc, otlptracehttp)?

[xue20xi]

I like this. I just added some cleanup comments. Hopefully these are my last comments 😉

Do you want to make similar PRs for other OTLP exporters (otlploghttp, otlpmetricgrpc, otlpmetrichttp, otlptracegrpc, otlptracehttp)?

Yes, I'd like to, if no other comments, will start to work on the other exporters

[pellared]

I made a little refactoring 63c83a4

@open-telemetry/go-approvers, PTAL

[xue20xi]

I like this. I just added some cleanup comments. Hopefully these are my last comments 😉
Do you want to make similar PRs for other OTLP exporters (otlploghttp, otlpmetricgrpc, otlpmetrichttp, otlptracegrpc, otlptracehttp)?

Yes, I'd like to, if no other comments, will start to work on the other exporters

I have checked the otlploghttp module, it seems the example for self-signed certificate is not needed.

It works fine when only specify the environment variable "OTEL_EXPORTER_OTLP_CERTIFICATE" for self-signed certificate TLS connection.
It works fine when only specify the environment variable "OTEL_EXPORTER_OTLP_CERTIFICATE", "OTEL_EXPORTER_OTLP_CLIENT_CERTIFICATE" and "OTEL_EXPORTER_OTLP_CLIENT_KEY" for self-signed certificate mTLS connection.

The reason is otlploghttp.New(ctx) will load the TLS config from the environment variables (newConfig() in otlploghttp/config.go )

So otlploghttp.WithTLSClientConfig() is not needed, this is align with the README (https://pkg.go.dev/go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploghttp)

OTEL_EXPORTER_OTLP_CERTIFICATE, OTEL_EXPORTER_OTLP_LOGS_CERTIFICATE (default: none) - the filepath to the trusted certificate to use when verifying a server's TLS credentials. OTEL_EXPORTER_OTLP_LOGS_CERTIFICATE takes precedence over OTEL_EXPORTER_OTLP_CERTIFICATE. The configuration can be overridden by WithTLSClientConfig option.

[pellared]

I have checked the otlploghttp module, it seems the example for self-signed certificate is not needed.

I quickly checked the otlploggrpc code and docs and I would suspect that this should work the same way as for otlploghttp. I have a strong feeling that my comment #6661 (comment) was incorrect (sorry for that).

Do you know of this issue is true for other gRPC OTLP exporters? I wouldn't be surprised if this is only a problem only in otlploggrpc.

[xue20xi]

I have checked the otlploghttp module, it seems the example for self-signed certificate is not needed.

I quickly checked the otlploggrpc code and docs and I would suspect that this should work the same way as for otlploghttp. I have a strong feeling that my comment #6661 (comment) was incorrect (sorry for that).

Do you know of this issue is true for other gRPC OTLP exporters? I wouldn't be surprised if this is only a problem only in otlploggrpc.

I have checked otlpmetricgrpc and otlptracegrpc, they both work fine, so you're right, it seems a problem only in otlploggrpc

[pellared]

@xue20xi, given the latest comment I think we can close the PR. Do you want to work on fixing #6661 given it seems to be a bug and you already know what code should be invoked so that it works properly? I mean the examples here work and this is the code that should be invoke when e.g. OTEL_EXPORTER_OTLP_LOGS_CERTIFICATE is set.