Attribute `http_route` is not recorded by server metric when using servlet 2.0/3.0.

[k3v1n1k88]

Describe the bug

While using the OpenTelemetry Java agent on an application that uses Servlet 2.0/3.0, the http_route attribute is not recorded by the server metrics. It appears as follows:

http_server_request_duration_seconds_count{http_request_method="POST",http_response_status_code="200",network_protocol_version="1.1",otel_scope_name="io.opentelemetry.jetty-8.0",otel_scope_version="2.8.0-alpha",url_scheme="http"}

Steps to reproduce

Here's a clearer and more structured version of your steps:

1. Build HTTP Server Using Jetty Embedded 9.3 (Servlet 3.0)

   • Create an HTTP server using Jetty embedded 9.3, which supports Servlet 3.0.

2. Run Java Agent with Prometheus Exporter Enabled on Port 9464

   • Start the application with the OpenTelemetry Java agent and enable the Prometheus exporter on port 9464:

     java -javaagent:opentelemetry-javaagent.jar -Dotel.metrics.exporter=prometheus -Dotel.exporter.prometheus.port=9464 -jar myapp.jar

3. Send a Request to the Application

   • Make a request to the running application to trigger the server-side metrics:

     curl http://localhost:8080/your-endpoint

4. Load Metrics via Prometheus

   • Retrieve the metrics exposed by the Prometheus exporter:

     curl http://localhost:9464/metrics

5. Find the http_server_request_duration_seconds_count Metric

   • Look for the http_server_request_duration_seconds_count metric in the Prometheus output to check the recorded server request duration.

Expected behavior

The metric http_server_request_duration_seconds_count should contain the http_route attribute

http_server_request_duration_seconds_count{http_request_method="POST",http_response_status_code="200",http_route="/api/hello",network_protocol_version="1.1",otel_scope_name="io.opentelemetry.jetty-8.0",otel_scope_version="2.8.0-alpha",url_scheme="http"} 1

Actual behavior

The metric http_server_request_duration_seconds_count does not contain the http_route attribute. http_server_request_duration_seconds_count{http_request_method="POST",http_response_status_code="200",network_protocol_version="1.1",otel_scope_name="io.opentelemetry.jetty-8.0",otel_scope_version="2.8.0-alpha",url_scheme="http"} 1`

Javaagent or library instrumentation version

2.8.0

Environment

JDK: OpenJDK 11.0.23 OS: Ubuntu 20.04 Jetty Embedded 9.3, Servlet 3

Additional context

No response

[laurit]

We believe that we can not provide a reasonable route based on just the servlets. If you are using a higher level framework it may be possible to instrument that framework to get a route.