[Trace SDK] OTLP Trace Exporter secure connection configuration options

[marcalff]

Greetings,

In the spec, for the OpenTelemetry Protocol Exporter configurations options:

https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/protocol/exporter.md#specifying-headers-via-environment-variables

The spec says:

The following configuration options MUST be available to configure the OTLP exporter. Each configuration option MUST be overridable by a signal specific option.

(...)

(1) Certificate File:

Env vars: OTEL_EXPORTER_OTLP_CERTIFICATE OTEL_EXPORTER_OTLP_TRACES_CERTIFICATE ...

(2) Client key file:

Env vars: OTEL_EXPORTER_OTLP_CLIENT_KEY OTEL_EXPORTER_OTLP_TRACES_CLIENT_KEY ...

(3) Client certificate file:

Env vars: OTEL_EXPORTER_OTLP_CLIENT_CERTIFICATE OTEL_EXPORTER_OTLP_TRACES_CLIENT_CERTIFICATE ...

Currently, opentelemetry-cpp supports the following environment variables:

• OTEL_EXPORTER_OTLP_CERTIFICATE
• OTEL_EXPORTER_OTLP_TRACES_CERTIFICATE
  which covers (1), per the spec.
• OTEL_EXPORTER_OTLP_CERTIFICATE_STRING
• OTEL_EXPORTER_OTLP_TRACES_CERTIFICATE_STRING
  which covers (1), in addition to the spec (great).

Implementation for (2) and (3) appear to be missing.

Also, secure connection options are only used for the OtlpGrpcExporter

Should the OtlpHttpExporter honor the same variables as well ?

Currently there are no security options in OtlpHttpExporterOptions.

My understanding from the spec is that secure options apply to the OTLP exporter in general: that is, to both OTLP/gRPC and OTLP/HTTP end points.

Regards.

[lalitb]

Implementation for (2) and (3) appear to be missing.

Client authentication is missing. There is open issue for that - #389, and some work done in #938

Should the OtlpHttpExporter honor the same variables as well ?

Yes security options should be there for both gRPC and HTTP.

[marcalff]

Thanks @lalitb for the clarifications.
Sorry I missed the existing issues.

[lalitb]

No problem. We can use this issue to track supporting secure options for OtlpHttpExporter.

[github-actions]

This issue was marked as stale due to lack of activity.

[rgc183]

Otlp grpc exporter is also missing default options for SSL: https://grpc.io/docs/guides/auth/#using-client-side-ssltls

// Create a default SSL ChannelCredentials object. auto channel_creds = grpc::SslCredentials(grpc::SslCredentialsOptions());

Update:
According to this: grpc/grpc#25829 (comment) certificate needs to be given explicitly.