Monitoring Elasticsearch Java REST Client by Elastic APM Java Agent - demo

ElasticsearchRestClientInstrumentation.java

public class ElasticsearchRestClientInstrumentation extends ElasticApmInstrumentation {
    private static class ElasticsearchRestClientAdvice {
        @Advice.OnMethodEnter(suppress = Throwable.class)
        private static void onBeforeExecute(@Advice.Argument(0) Request request,
                                            @Advice.Local("span") Span span) {
            span = tracer.getActive().createSpan()
                    .withType("db").withSubtype("elasticsearch").withAction("request")
                    .appendToName("Elasticsearch: ").appendToName(request.getMethod())
                    .appendToName(" ").appendToName(request.getEndpoint());
            span.getContext().getDb().withType("elasticsearch");
            span.activate();
            span.getContext().getHttp().withMethod(request.getMethod());
            if (request.getEndpoint().endsWith("_search")) {
                HttpEntity entity = request.getEntity();
                if (entity != null && entity.isRepeatable()) {
                    IOUtils.readUtf8Stream(entity.getContent(),
                            span.getContext().getDb().withStatementBuffer());
                }
            }
        }

        @Advice.OnMethodExit(suppress = Throwable.class, onThrowable = Throwable.class)
        public static void onAfterExecute(@Advice.Return @Nullable Response response,
                                          @Advice.Local("span") @Nullable Span span,
                                          @Advice.Thrown @Nullable Throwable t) {
            try {
                String url = null; int statusCode = -1;
                if (response != null) {
                    url = response.getHost().toURI();
                    statusCode = response.getStatusLine().getStatusCode();
                } else if (t != null) {
                    if (t instanceof ResponseException) {
                        ResponseException esre = (ResponseException) t;
                        url = esre.getResponse().getHost().toURI();
                        statusCode = esre.getResponse().getStatusLine().getStatusCode();
                    }
                    span.captureException(t);}
                span.getContext().getHttp().withUrl(url);
                span.getContext().getHttp().withStatusCode(statusCode);
            } finally {
                span.deactivate().end();
            }
        }
    }

    public Class<?> getAdviceClass() {
        return ElasticsearchRestClientAdvice.class;
    }

    public ElementMatcher<? super TypeDescription> getTypeMatcher() {
        return named("org.elasticsearch.client.RestClient");
    }

    public ElementMatcher<? super MethodDescription> getMethodMatcher() {
        return named("performRequest").and(takesArguments(1)
                .and(takesArgument(0, named("org.elasticsearch.client.Request"))));
    }
}