PHP doesnt follow Otel spec to not capture custom http headers by default.

[HeenaBansal20]

Does PHP supports any explicit config to capture custom http headers.?

http.request.header: Instrumentations SHOULD require an explicit configuration of which headers are to be captured. Including all request headers can be a security risk - explicit configuration helps avoid leaking sensitive information. The User-Agent header is already captured in the user_agent.original attribute. Users MAY explicitly configure instrumentations to capture them even though it is not recommended. The attribute value MUST consist of either multiple header values as an array of strings or a single-item array containing a possibly comma-concatenated string, depending on the way the HTTP library provides access to headers.

[brettmc]

Most of our http-based auto-instrumentation packages allow capturing request and response headers, eg https://github.com/open-telemetry/opentelemetry-php-contrib/blob/main/src/Instrumentation/Psr18/src/Psr18Instrumentation.php#L74
Is this what you mean?

[HeenaBansal20]

yes , but this is library specific implementation ... I am also looking something like OTEL_PHP_ config whose scope is wider and applicable to each auto instrumented library ?

Do we have something like it exists for JAVA , https://opentelemetry.io/docs/zero-code/java/agent/instrumentation/http/

[HeenaBansal20]

IS this setting can be used PHP wide for all instrumented libraries by otel "otel.instrumentation.http.request_headers"?
I see that curl library supports these variables. Is this specific to curl library or it can also be used with any auto I instrumented libraries.

OTEL_PHP_INSTRUMENTATION_HTTP_RESPONSE_HEADERS=content-type,server
OTEL_PHP_INSTRUMENTATION_HTTP_REQUEST_HEADERS=host,accept