Cannot Capture Custom Headers from Instrumented Servers

[baole229801]

Describe the bug

Hi everyone,
I have attached the java opentelemetry agent to our application, anh I want to capture one custom header from its response to the clients.

This is the response header:

Date: Tue, 25 Feb 2025 06:12:47 GMT
X-Content-Type-Options: nosniff
Content-Length: 0
X-ORACLE-DMS-ECID: 006Bj5OWiBcA_MYjLp2VOA00060m000JuW
X-ORACLE-DMS-RID: 0:1
X-XSS-Protection: 1; mode=block
Keep-Alive: timeout=5, max=1000
Connection: Keep-Alive
Content-Type: text/xml; charset=iso-8859-1

And inside properties file, I use this configration:

otel.instrumentation.http.server.capture-response-headers=Content-Type,X-ORACLE-DMS-ECID

I dont understand why it only captures the Content-Type, but not the X-ORACLE-DMS-ECID header. Is there any additional configuration for the custom header.

Thank everyone.

Steps to reproduce

This is the response header:

Date: Tue, 25 Feb 2025 06:12:47 GMT
X-Content-Type-Options: nosniff
Content-Length: 0
X-ORACLE-DMS-ECID: 006Bj5OWiBcA_MYjLp2VOA00060m000JuW
X-ORACLE-DMS-RID: 0:1
X-XSS-Protection: 1; mode=block
Keep-Alive: timeout=5, max=1000
Connection: Keep-Alive
Content-Type: text/xml; charset=iso-8859-1

The configuration:

otel.instrumentation.http.server.capture-response-headers=Content-Type,X-ORACLE-DMS-ECID

Expected behavior

It should show both values for the configured headers.

Actual behavior

It should show both values for the configured headers.

Javaagent or library instrumentation version

1.37

Environment

JDK:
OS:

Additional context

No response

[laurit]

Is this weblogic or some other server? Can you observe these headers being set when you call HttpServletResponse.getHeaderNames() or HttpServletResponse.getHeaders()?

[baole229801]

Hi Laurit,
This is Weblogic and the application is Oracle Service Bus.

From the client side, when I set to otel.instrumentation.http.client.capture-response-headers=X-ORACLE-DMS-ECID, I can get the header's value.