Make Otlp exporter configuration environment variables specs-compliant

[lalitb]

Fixes #971

Changes

This PR makes otlp exporter configuration environment variables specs compliant.
Also add one new env variable ( not part of specs ) - OTEL_EXPORTER_OTLP_CERTIFICATE_STRING to specify certificate as string.

Also introduce new env-variables ( not part of specs ) `

For significant contributions please make sure you have completed the following items:

• CHANGELOG.md updated for non-trivial changes
• Unit tests have been added
• Changes in public API reviewed

[codecov]

Codecov Report

Merging #974 (c192b58) into main (0da25b3) will not change coverage.
The diff coverage is n/a.

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  Hits         6502     6502           
  Misses        315      315           

[jsuereth]

Commented on the bug as well.

I don't think this is sufficient for a 1.0 against the specification.

I think there are two enviornment variables here that you can leave for legacy users BUT you should provide the new environment variables as alternatives, specifically:

OTEL_EXPORTER_OTLP_TRACES_ENDPOINT and OTEL_EXPORTER_OTLP_TRACES_CERTIFICATE

[lalitb]

@jsuereth - It was creating more noise in code to support both legacy and compliant environment variables, and would further increase in future once we start supporting OTEL_EXPORTER_OTLP_[TRACES_]PROTOCOL. Keeping that in mind, have removed legacy environment variables. This would be breaking change ( hopefully won't affect lots of users ), and we will document this in release description.

[lalitb]

will remove this commit later.

[lalitb]

@owent - As these env variables were initially modified by you, would like to have a look into this PR. Thanks.

[owent]

@owent - As these env variables were initially modified by you, would like to have a look into this PR. Thanks.

LGTM.

Should we also make the same changes for OtlpHttpExporter ?

[lalitb]

LGTM.

Should we also make the same changes for OtlpHttpExporter ?

Thanks for reviewing @owais. OtlpHttpExporter doesn't support environment variables yet, so we are not non-compliant there :) Will create a github issue for adding env variables there.

[owent]

LGTM.
Should we also make the same changes for OtlpHttpExporter ?

Thanks for reviewing @owais. OtlpHttpExporter doesn't support environment variables yet, so we are not non-compliant there :) Will create a github issue for adding env variables there.

OK. I think I can add support of these environment variables for OtlpHttpExporter then:

• OTEL_EXPORTER_OTLP_ENDPOINT
• OTEL_EXPORTER_OTLP_TRACES_ENDPOINT
• OTEL_EXPORTER_OTLP_HEADERS
• OTEL_EXPORTER_OTLP_TRACES_HEADERS
• OTEL_EXPORTER_OTLP_TIMEOUT
• OTEL_EXPORTER_OTLP_TRACES_TIMEOUT

But OTEL_EXPORTER_OTLP_CERTIFICATE and OTEL_EXPORTER_OTLP_TRACES_CERTIFICATE can be available only after #938 is finished.

[lalitb]

OK. I think I can add support of these environment variables for OtlpHttpExporter then:

• OTEL_EXPORTER_OTLP_ENDPOINT
• OTEL_EXPORTER_OTLP_TRACES_ENDPOINT
• OTEL_EXPORTER_OTLP_HEADERS
• OTEL_EXPORTER_OTLP_TRACES_HEADERS
• OTEL_EXPORTER_OTLP_TIMEOUT
• OTEL_EXPORTER_OTLP_TRACES_TIMEOUT

That would be awesome :)

But OTEL_EXPORTER_OTLP_CERTIFICATE and OTEL_EXPORTER_OTLP_TRACES_CERTIFICATE can be available only after #938 is finished.

Agree.