[jira] [Created] (CAMEL-24505) camel-micrometer-starter - uri metric tag falls back to the raw request path, giving unbounded tag cardinality

["Andrea Cosentino (Jira)" <ji...@apache.org>]

Andrea Cosentino created CAMEL-24505:
----------------------------------------

             Summary: camel-micrometer-starter - uri metric tag falls back to the raw request path, giving unbounded tag cardinality
                 Key: CAMEL-24505
                 URL: https://issues.apache.org/jira/browse/CAMEL-24505
             Project: Camel
          Issue Type: Improvement
          Components: camel-spring-boot-starters, camel-micrometer
            Reporter: Andrea Cosentino
            Assignee: Andrea Cosentino


{{MicrometerTagsAutoConfiguration.custom()}} builds the {{uri}} tag for the servlet observation:

{code:java}
if (servlet.isPresent() && !configuration.isUriTagDynamic()) {
    HttpConsumer consumer = servlet.get().getServletResolveConsumerStrategy().resolve(request, servlet.get().getConsumers());
    if (consumer != null) {
        uri = consumer.getPath();
    }
}

// the request may not be for camel servlet, so we need to capture uri from request
if (uri == null || uri.isEmpty()) {
    uri = request.getServletPath();
    if (uri == null || uri.isEmpty()) {
        uri = request.getPathInfo();
    } else {
        String p = request.getPathInfo();
        if (p != null) {
            uri = uri + p;
        }
    }
}
{code}

(MicrometerTagsAutoConfiguration:70)

When the request does not resolve to a Camel consumer - any 404, any request to a non-Camel path - the tag value becomes the request path verbatim. Micrometer creates one meter per distinct tag value and keeps them for the process lifetime, so the number of meters follows the number of distinct paths requested rather than the number of routes.

Spring's own convention for this case is a constant {{UNKNOWN}} tag, precisely because the value is client-supplied. Only the resolved consumer path template is a bounded, route-author-authored value.

*Proposal*

- Replace the raw {{servletPath}}/{{pathInfo}} fallback with a constant such as {{UNKNOWN}}.
- Keep the raw path only behind the existing {{uriTagDynamic}} opt-in, and normalise or cap it there.
- Add a test asserting that N requests to N distinct unmatched paths produce one meter, not N.

----
_This issue was drafted by Claude Code on behalf of Andrea Cosentino._



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