Including spring boot endpoint path variable as a metric dimension

Question

I have api endpoint : /user/{tenant}/create

I am using spring boot 2 with micrometer for metrics.

By default @Timer annotation for spring boot 2 endpoint includes the following tags: exception,method, uri, status

I want to add the passed value for api parameter "tenant" as an extra tag for the endpoint

How do I do that with spring boot 2 and micrometer

Answer 1

Use custom WebMvcTagsProvider, e.g.:

@Bean
public WebMvcTagsProvider webMvcTagsProvider() {
    return new WebMvcTagsProvider() {
        @Override
        public Iterable<Tag> getTags(HttpServletRequest request, HttpServletResponse response, Object handler, Throwable exception) {
            return ((Map<String, String>) request.getAttribute(HandlerMapping.URI_TEMPLATE_VARIABLES_ATTRIBUTE))
                    .entrySet()
                    .stream()
                    .map(entry -> new ImmutableTag(entry.getKey(), entry.getValue()))
                    .collect(Collectors.toList());
        }

        @Override
        public Iterable<Tag> getLongRequestTags(HttpServletRequest request, Object handler) {
            return new ArrayList<>();
        }
    };
}