com.linecorp.armeria.common.metric.PrometheusMeterRegistries Java Examples

@Test
public void sameCacheTwice() {
    final MockCache cache = new MockCache(1, 2, 3, 4, 5);
    final MeterRegistry registry = PrometheusMeterRegistries.newRegistry();
    final MeterIdPrefix idPrefix = new MeterIdPrefix("baz");

    // Register the same cache twice at the same meter ID.
    CaffeineMetricSupport.setup(registry, idPrefix, cache);
    CaffeineMetricSupport.setup(registry, idPrefix, cache);

    // .. and check if the stats are *not* doubled.
    assertThat(MoreMeters.measureAll(registry))
            .containsEntry("baz.requests#count{result=hit}", 1.0)
            .containsEntry("baz.requests#count{result=miss}", 2.0)
            .containsEntry("baz.evictions#count", 3.0)
            .containsEntry("baz.eviction.weight#count", 4.0)
            .containsEntry("baz.estimated.size#value", 5.0);
}
 

@Test
public void aggregation() {
    final MockLoadingCache cache1 = new MockLoadingCache(1, 2, 3, 4, 5, 6, 7, 8);
    final MockLoadingCache cache2 = new MockLoadingCache(9, 10, 11, 12, 13, 14, 15, 16);
    final MeterRegistry registry = PrometheusMeterRegistries.newRegistry();
    final MeterIdPrefix idPrefix = new MeterIdPrefix("baz");

    // Register two caches at the same meter ID.
    CaffeineMetricSupport.setup(registry, idPrefix, cache1);
    CaffeineMetricSupport.setup(registry, idPrefix, cache2);

    // .. and their stats are aggregated.
    assertThat(MoreMeters.measureAll(registry))
            .containsEntry("baz.requests#count{result=hit}", 10.0)
            .containsEntry("baz.requests#count{result=miss}", 12.0)
            .containsEntry("baz.loads#count{result=success}", 14.0)
            .containsEntry("baz.loads#count{result=failure}", 16.0)
            .containsEntry("baz.load.duration#count", 18.0)
            .containsEntry("baz.evictions#count", 20.0)
            .containsEntry("baz.eviction.weight#count", 22.0)
            .containsEntry("baz.estimated.size#value", 24.0);
}
 

@Test
public void testNonLoadingCache() {
    final MockCache cache = new MockCache(1, 2, 3, 4, 5);
    final AtomicLong ticker = new AtomicLong();
    final MeterRegistry registry = PrometheusMeterRegistries.newRegistry();
    CaffeineMetricSupport.setup(registry, new MeterIdPrefix("bar"), cache, ticker::get);

    assertThat(cache.statsCalls()).isOne();
    assertThat(cache.estimatedSizeCalls()).isOne();

    assertThat(MoreMeters.measureAll(registry))
            .containsEntry("bar.requests#count{result=hit}", 1.0)
            .containsEntry("bar.requests#count{result=miss}", 2.0)
            .containsEntry("bar.evictions#count", 3.0)
            .containsEntry("bar.eviction.weight#count", 4.0)
            .containsEntry("bar.estimated.size#value", 5.0);

    // Make sure the meters related with loading are not registered.
    assertThat(MoreMeters.measureAll(registry)).doesNotContainKeys(
            "bar.loads#count{result=success}",
            "bar.loads#count{result=failure}",
            "bar.load.duration#count");
}
 

@Test
void rpc() {
    final MeterRegistry registry = PrometheusMeterRegistries.newRegistry();
    final ClientRequestContext ctx =
            ClientRequestContext.builder(HttpRequest.of(HttpMethod.POST, "/bar"))
                                .meterRegistry(registry)
                                .endpoint(Endpoint.of("example.com", 8080))
                                .build();

    final MeterIdPrefixFunction meterIdPrefixFunction = MeterIdPrefixFunction.ofDefault("bar");
    RequestMetricSupport.setup(ctx, REQUEST_METRICS_SET, meterIdPrefixFunction, false);

    ctx.logBuilder().name("BarService", "baz");

    assertThat(measureAll(registry))
            .containsEntry("bar.active.requests#value{method=baz,service=BarService}", 1.0);
}
 

@Test
void writeTimedOutInClientSide() {
    final MeterRegistry registry = PrometheusMeterRegistries.newRegistry();
    final ClientRequestContext ctx = setupClientRequestCtx(registry);

    ctx.logBuilder().endRequest(WriteTimeoutException.get());
    ctx.logBuilder().endResponse(WriteTimeoutException.get());

    final Map<String, Double> measurements = measureAll(registry);
    assertThat(measurements)
            .containsEntry("foo.active.requests#value{method=POST}", 0.0)
            .containsEntry("foo.requests#count{http.status=0,method=POST,result=success}", 0.0)
            .containsEntry("foo.requests#count{http.status=0,method=POST,result=failure}", 1.0)
            .containsEntry("foo.timeouts#count{cause=WriteTimeoutException,http.status=0,method=POST}", 1.0)
            .containsEntry("foo.timeouts#count{cause=ResponseTimeoutException," +
                           "http.status=0,method=POST}", 0.0)
            .containsEntry("foo.response.duration#count{http.status=0,method=POST}", 0.0)
            .containsEntry("foo.response.length#count{http.status=0,method=POST}", 0.0)
            .containsEntry("foo.total.duration#count{http.status=0,method=POST}", 0.0);
}
 

@Test
void responseTimedOutInClientSide() {
    final MeterRegistry registry = PrometheusMeterRegistries.newRegistry();
    final ClientRequestContext ctx = setupClientRequestCtx(registry);

    ctx.logBuilder().requestFirstBytesTransferred();
    ctx.logBuilder().endRequest();
    ctx.logBuilder().endResponse(ResponseTimeoutException.get());

    final Map<String, Double> measurements = measureAll(registry);
    assertThat(measurements)
            .containsEntry("foo.active.requests#value{method=POST}", 0.0)
            .containsEntry("foo.requests#count{http.status=0,method=POST,result=success}", 0.0)
            .containsEntry("foo.requests#count{http.status=0,method=POST,result=failure}", 1.0)
            .containsEntry("foo.timeouts#count{cause=WriteTimeoutException,http.status=0,method=POST}", 0.0)
            .containsEntry("foo.timeouts#count{cause=ResponseTimeoutException," +
                           "http.status=0,method=POST}", 1.0)
            .containsEntry("foo.response.duration#count{http.status=0,method=POST}", 1.0)
            .containsEntry("foo.response.length#count{http.status=0,method=POST}", 1.0)
            .containsEntry("foo.total.duration#count{http.status=0,method=POST}", 1.0);
}
 

@Test
void httpFailure() {
    final MeterRegistry registry = PrometheusMeterRegistries.newRegistry();
    final ClientRequestContext ctx = setupClientRequestCtx(registry);

    ctx.logBuilder().requestFirstBytesTransferred();
    ctx.logBuilder().responseHeaders(ResponseHeaders.of(500));
    ctx.logBuilder().responseFirstBytesTransferred();
    ctx.logBuilder().responseLength(456);
    ctx.logBuilder().endRequest();
    ctx.logBuilder().endResponse();

    final Map<String, Double> measurements = measureAll(registry);
    assertThat(measurements)
            .containsEntry("foo.active.requests#value{method=POST}", 0.0)
            .containsEntry("foo.requests#count{http.status=500,method=POST,result=success}", 0.0)
            .containsEntry("foo.requests#count{http.status=500,method=POST,result=failure}", 1.0)
            .containsEntry("foo.response.duration#count{http.status=500,method=POST}", 1.0)
            .containsEntry("foo.response.length#count{http.status=500,method=POST}", 1.0)
            .containsEntry("foo.total.duration#count{http.status=500,method=POST}", 1.0);
}
 

@Test
public void notRecording() {
    when(policy.isRecordingStats()).thenReturn(false);
    final MockLoadingCache cache = new MockLoadingCache(1, 2, 3, 4, 5, 6, 7, 8);
    final AtomicLong ticker = new AtomicLong();
    final MeterRegistry registry = PrometheusMeterRegistries.newRegistry();
    CaffeineMetricSupport.setup(registry, new MeterIdPrefix("foo"), cache, ticker::get);
    assertThat(registry.getMeters()).isEmpty();
}
 

@Test
void requestTimedOutInServerSide() {
    final MeterRegistry registry = PrometheusMeterRegistries.newRegistry();
    final ServiceRequestContext ctx =
            ServiceRequestContext.builder(HttpRequest.of(HttpMethod.POST, "/foo"))
                                 .meterRegistry(registry)
                                 .build();
    final String serviceTag = "service=" + ctx.config().service().getClass().getName();

    final MeterIdPrefixFunction meterIdPrefixFunction = MeterIdPrefixFunction.ofDefault("foo");
    RequestMetricSupport.setup(ctx, REQUEST_METRICS_SET, meterIdPrefixFunction, true);

    ctx.logBuilder().requestFirstBytesTransferred();
    ctx.logBuilder().responseHeaders(ResponseHeaders.of(503)); // 503 when request timed out
    ctx.logBuilder().responseFirstBytesTransferred();
    ctx.logBuilder().responseLength(456);
    ctx.logBuilder().endRequest();
    ctx.logBuilder().endResponse(RequestTimeoutException.get());

    final Map<String, Double> measurements = measureAll(registry);
    assertThat(measurements)
            .containsEntry("foo.active.requests#value{hostname.pattern=*,method=POST," + serviceTag + '}',
                           0.0)
            .containsEntry("foo.requests#count{hostname.pattern=*,http.status=503,method=POST," +
                           "result=success," + serviceTag + '}', 0.0)
            .containsEntry("foo.requests#count{hostname.pattern=*,http.status=503,method=POST," +
                           "result=failure," + serviceTag + '}', 1.0)
            .containsEntry("foo.timeouts#count{cause=RequestTimeoutException,hostname.pattern=*," +
                           "http.status=503,method=POST," + serviceTag + '}', 1.0)
            .containsEntry("foo.response.duration#count{hostname.pattern=*,http.status=503,method=POST," +
                           serviceTag + '}', 1.0)
            .containsEntry("foo.response.length#count{hostname.pattern=*,http.status=503,method=POST," +
                           serviceTag + '}', 1.0)
            .containsEntry("foo.total.duration#count{hostname.pattern=*,http.status=503,method=POST," +
                           serviceTag + '}', 1.0);
}
 

@Test
void actualRequestsIncreasedWhenRetrying() {
    final MeterRegistry registry = PrometheusMeterRegistries.newRegistry();
    final ClientRequestContext ctx = setupClientRequestCtx(registry);

    addLogInfoInDerivedCtx(ctx);

    Map<String, Double> measurements = measureAll(registry);
    assertThat(measurements).containsEntry("foo.active.requests#value{method=POST}", 1.0);

    addLogInfoInDerivedCtx(ctx);
    // Does not increase the active requests.
    assertThat(measurements).containsEntry("foo.active.requests#value{method=POST}", 1.0);

    ctx.logBuilder().endResponseWithLastChild();

    measurements = measureAll(registry);
    assertThat(measurements)
            .containsEntry("foo.active.requests#value{method=POST}", 0.0)
            .containsEntry("foo.requests#count{http.status=500,method=POST,result=success}", 0.0)
            .containsEntry("foo.requests#count{http.status=500,method=POST,result=failure}", 1.0)
            .containsEntry("foo.actual.requests#count{http.status=500,method=POST}", 2.0)
            .containsEntry("foo.connection.acquisition.duration#count{http.status=500,method=POST}", 1.0)
            .containsEntry("foo.dns.resolution.duration#count{http.status=500,method=POST}", 1.0)
            .containsEntry("foo.socket.connect.duration#count{http.status=500,method=POST}", 1.0)
            .containsEntry("foo.pending.acquisition.duration#count{http.status=500,method=POST}", 1.0)
            .containsEntry("foo.request.length#count{http.status=500,method=POST}", 1.0)
            .containsEntry("foo.request.length#total{http.status=500,method=POST}", 123.0)
            .containsEntry("foo.response.duration#count{http.status=500,method=POST}", 1.0)
            .containsEntry("foo.response.length#count{http.status=500,method=POST}", 1.0)
            .containsEntry("foo.response.length#total{http.status=500,method=POST}", 456.0)
            .containsEntry("foo.total.duration#count{http.status=500,method=POST}", 1.0);
}
 

@Override
protected void configure(ServerBuilder sb) throws Exception {
    sb.meterRegistry(PrometheusMeterRegistries.newRegistry());
    sb.serviceUnder("/qux/", composite);

    // Should not hit the following services
    sb.serviceUnder("/foo/", otherService);
    sb.serviceUnder("/bar/", otherService);
    sb.service(Route.builder().glob("/*").build(), otherService);
}
 

@Test
void monitorBlockingTaskExecutorAndSchedulersTogetherWithPrometheus() {
    final PrometheusMeterRegistry registry = PrometheusMeterRegistries.newRegistry();
    Metrics.addRegistry(registry);
    Server.builder()
          .meterRegistry(registry)
          .service("/", (ctx, req) -> HttpResponse.of(200))
          .build();
    Schedulers.enableMetrics();
    Schedulers.decorateExecutorService(Schedulers.single(), Executors.newSingleThreadScheduledExecutor());
}
 

@Test
void metrics() {
    final MeterRegistry meterRegistry = PrometheusMeterRegistries.newRegistry();
    final Repository repo = newCachingRepo(meterRegistry);
    final Map<String, Double> meters = MoreMeters.measureAll(meterRegistry);
    assertThat(meters).containsKeys("cache.load#count{cache=repository,result=success}");

    // Do something with 'repo' so that it is not garbage-collected even before the meters are measured.
    assertThat(repo.normalizeNow(HEAD)).isNotEqualTo("");
}
 

Replica(InstanceSpec spec, Map<Integer, ZooKeeperAddress> servers,
        Function<Command<?>, CompletableFuture<?>> delegate, boolean start) throws Exception {
    this.delegate = delegate;

    dataDir = spec.getDataDirectory();
    meterRegistry = PrometheusMeterRegistries.newRegistry();

    final int id = spec.getServerId();
    final ZooKeeperReplicationConfig zkCfg = new ZooKeeperReplicationConfig(id, servers);

    rm = new ZooKeeperCommandExecutor(zkCfg, dataDir, new AbstractCommandExecutor(null, null) {
        @Override
        public int replicaId() {
            return id;
        }

        @Override
        protected void doStart(@Nullable Runnable onTakeLeadership,
                               @Nullable Runnable onReleaseLeadership) {}

        @Override
        protected void doStop(@Nullable Runnable onReleaseLeadership) {}

        @Override
        @SuppressWarnings("unchecked")
        protected <T> CompletableFuture<T> doExecute(Command<T> command) {
            return (CompletableFuture<T>) delegate.apply(command);
        }
    }, meterRegistry, null, null);

    startFuture = start ? rm.start() : null;
}
 

@Test
void httpSuccess() {
    final MeterRegistry registry = PrometheusMeterRegistries.newRegistry();
    final ClientRequestContext ctx = setupClientRequestCtx(registry);

    // FIXME(trustin): In reality, most HTTP requests will not have any name.
    //                 As a result, `activeRequestPrefix()` will be invoked only after
    //                 a request is completed, i.e. active request count will be inaccurate,
    //                 especially for streaming requests.
    ctx.logBuilder().name("FooService", "POST");

    Map<String, Double> measurements = measureAll(registry);
    assertThat(measurements).containsEntry("foo.active.requests#value{method=POST,service=FooService}",
                                           1.0);

    ctx.logBuilder().requestFirstBytesTransferred();
    ctx.logBuilder().requestLength(123);
    ctx.logBuilder().endRequest();

    ctx.logBuilder().responseHeaders(ResponseHeaders.of(200));
    ctx.logBuilder().responseLength(456);
    ctx.logBuilder().endResponse();

    measurements = measureAll(registry);
    assertThat(measurements)
            .containsEntry("foo.active.requests#value{method=POST,service=FooService}", 0.0)
            .containsEntry("foo.requests#count{http.status=200,method=POST,result=success," +
                           "service=FooService}", 1.0)
            .containsEntry("foo.requests#count{http.status=200,method=POST,result=failure," +
                           "service=FooService}", 0.0)
            .containsEntry("foo.connection.acquisition.duration#count{http.status=200,method=POST," +
                           "service=FooService}", 1.0)
            .containsEntry("foo.dns.resolution.duration#count{http.status=200,method=POST," +
                           "service=FooService}", 1.0)
            .containsEntry("foo.socket.connect.duration#count{http.status=200,method=POST," +
                           "service=FooService}", 1.0)
            .containsEntry("foo.pending.acquisition.duration#count{http.status=200,method=POST," +
                           "service=FooService}", 1.0)
            .containsEntry("foo.request.length#count{http.status=200,method=POST," +
                           "service=FooService}", 1.0)
            .containsEntry("foo.request.length#total{http.status=200,method=POST," +
                           "service=FooService}", 123.0)
            .containsEntry("foo.response.duration#count{http.status=200,method=POST," +
                           "service=FooService}", 1.0)
            .containsEntry("foo.response.length#count{http.status=200,method=POST," +
                           "service=FooService}", 1.0)
            .containsEntry("foo.response.length#total{http.status=200,method=POST," +
                           "service=FooService}", 456.0)
            .containsEntry("foo.total.duration#count{http.status=200,method=POST," +
                           "service=FooService}", 1.0)
            // This metric is inserted only when RetryingClient is Used.
            .doesNotContainKey("foo.actual.requests#count{http.status=200,method=POST," +
                               "service=FooService}");
}
 

@Test
void test() throws Exception {
    final MeterRegistry registry = PrometheusMeterRegistries.newRegistry();
    final CircuitBreakerListener l = new MetricCollectingCircuitBreakerListener(registry, "foo");

    // Note: We only use the name of the circuit breaker.
    final CircuitBreaker cb = CircuitBreaker.builder("bar").build();

    // Trigger the first event so that the metric group is registered.
    l.onEventCountUpdated(cb.name(), EventCount.of(1, 2));

    assertThat(MoreMeters.measureAll(registry))
            .containsEntry("foo.state#value{name=bar}", 1.0)
            .containsEntry("foo.requests#value{name=bar,result=success}", 1.0)
            .containsEntry("foo.requests#value{name=bar,result=failure}", 2.0)
            .containsEntry("foo.transitions#count{name=bar,state=CLOSED}", 0.0)
            .containsEntry("foo.transitions#count{name=bar,state=OPEN}", 0.0)
            .containsEntry("foo.transitions#count{name=bar,state=HALF_OPEN}", 0.0)
            .containsEntry("foo.rejected.requests#count{name=bar}", 0.0);

    // Transit to CLOSED.
    l.onStateChanged(cb.name(), CircuitState.CLOSED);
    assertThat(MoreMeters.measureAll(registry))
            .containsEntry("foo.state#value{name=bar}", 1.0)
            .containsEntry("foo.transitions#count{name=bar,state=CLOSED}", 1.0);

    // Transit to OPEN.
    l.onStateChanged(cb.name(), CircuitState.OPEN);
    assertThat(MoreMeters.measureAll(registry))
            .containsEntry("foo.state#value{name=bar}", 0.0)
            .containsEntry("foo.transitions#count{name=bar,state=OPEN}", 1.0);

    // Transit to HALF_OPEN.
    l.onStateChanged(cb.name(), CircuitState.HALF_OPEN);
    assertThat(MoreMeters.measureAll(registry))
            .containsEntry("foo.state#value{name=bar}", 0.5)
            .containsEntry("foo.transitions#count{name=bar,state=HALF_OPEN}", 1.0);

    // Reject a request.
    l.onRequestRejected(cb.name());
    assertThat(MoreMeters.measureAll(registry))
            .containsEntry("foo.rejected.requests#count{name=bar}", 1.0);
}
 

@Test
void serviceAndClientContext() {
    final MeterRegistry registry = PrometheusMeterRegistries.newRegistry();
    final ServiceRequestContext sctx =
            ServiceRequestContext.builder(HttpRequest.of(HttpMethod.POST, "/foo"))
                                 .meterRegistry(registry)
                                 .build();
    final String serviceTag = "service=" + sctx.config().service().getClass().getName();

    RequestMetricSupport.setup(sctx, REQUEST_METRICS_SET, MeterIdPrefixFunction.ofDefault("foo"), true);
    sctx.logBuilder().endRequest();
    try (SafeCloseable ignored = sctx.push()) {
        final ClientRequestContext cctx =
                ClientRequestContext.builder(HttpRequest.of(HttpMethod.POST, "/foo"))
                                    .meterRegistry(registry)
                                    .endpoint(Endpoint.of("example.com", 8080))
                                    .build();
        RequestMetricSupport.setup(cctx, AttributeKey.valueOf("differentKey"),
                                   MeterIdPrefixFunction.ofDefault("bar"), false);
        cctx.logBuilder().endRequest();
        cctx.logBuilder().responseHeaders(ResponseHeaders.of(200));
        cctx.logBuilder().endResponse();
    }
    sctx.logBuilder().responseHeaders(ResponseHeaders.of(200));
    sctx.logBuilder().endResponse();

    final Map<String, Double> measurements = measureAll(registry);
    assertThat(measurements)
            // clientRequestContext
            .containsEntry("bar.active.requests#value{method=POST}", 0.0)
            .containsEntry("bar.requests#count{http.status=200,method=POST,result=success}", 1.0)
            .containsEntry("bar.requests#count{http.status=200,method=POST,result=failure}", 0.0)
            .containsEntry("bar.response.duration#count{http.status=200,method=POST}", 1.0)
            .containsEntry("bar.response.length#count{http.status=200,method=POST}", 1.0)
            .containsEntry("bar.total.duration#count{http.status=200,method=POST}", 1.0)
            // serviceRequestContext
            .containsEntry("foo.active.requests#value{hostname.pattern=*,method=POST," +
                           serviceTag + '}', 0.0)
            .containsEntry("foo.requests#count{hostname.pattern=*,http.status=200,method=POST," +
                           "result=success," + serviceTag + '}', 1.0)
            .containsEntry("foo.requests#count{hostname.pattern=*,http.status=200,method=POST," +
                           "result=failure," + serviceTag + '}', 0.0)
            .containsEntry("foo.response.duration#count{hostname.pattern=*,http.status=200,method=POST," +
                           serviceTag + '}', 1.0)
            .containsEntry("foo.response.length#count{hostname.pattern=*,http.status=200,method=POST," +
                           serviceTag + '}', 1.0)
            .containsEntry("foo.total.duration#count{hostname.pattern=*,http.status=200,method=POST," +
                           serviceTag + '}', 1.0);
}
 

@Test
public void test() {
    final MockLoadingCache cache = new MockLoadingCache(1, 2, 3, 4, 5, 6, 7, 8);
    final AtomicLong ticker = new AtomicLong();
    final MeterRegistry registry = PrometheusMeterRegistries.newRegistry();
    CaffeineMetricSupport.setup(registry, new MeterIdPrefix("foo"), cache, ticker::get);
    assertThat(registry.getMeters()).isNotEmpty();

    assertThat(cache.statsCalls()).isOne();
    assertThat(cache.estimatedSizeCalls()).isOne();

    assertThat(MoreMeters.measureAll(registry))
            .containsEntry("foo.requests#count{result=hit}", 1.0)
            .containsEntry("foo.requests#count{result=miss}", 2.0)
            .containsEntry("foo.loads#count{result=success}", 3.0)
            .containsEntry("foo.loads#count{result=failure}", 4.0)
            .containsEntry("foo.load.duration#count", 5.0)
            .containsEntry("foo.evictions#count", 6.0)
            .containsEntry("foo.eviction.weight#count", 7.0)
            .containsEntry("foo.estimated.size#value", 8.0);

    // Make sure Cache.stats() and estimatedSize() are not called since the initial update.
    assertThat(cache.statsCalls()).isOne();
    assertThat(cache.estimatedSizeCalls()).isOne();

    // Advance the ticker so that the next collection triggers stats() and estimatedSize().
    ticker.addAndGet(CaffeineMetricSupport.UPDATE_INTERVAL_NANOS);
    cache.update(9, 10, 11, 12, 13, 14, 15, 16);

    assertThat(MoreMeters.measureAll(registry))
            .containsEntry("foo.requests#count{result=hit}", 9.0)
            .containsEntry("foo.requests#count{result=miss}", 10.0)
            .containsEntry("foo.loads#count{result=success}", 11.0)
            .containsEntry("foo.loads#count{result=failure}", 12.0)
            .containsEntry("foo.load.duration#count", 13.0)
            .containsEntry("foo.evictions#count", 14.0)
            .containsEntry("foo.eviction.weight#count", 15.0)
            .containsEntry("foo.estimated.size#value", 16.0);

    // Make sure Cache.stats() and estimatedSize() were called once more since the initial update.
    assertThat(cache.statsCalls()).isEqualTo(2);
    assertThat(cache.estimatedSizeCalls()).isEqualTo(2);
}
 

@Provides
@Singleton
static MeterRegistry meterRegistry(CollectorRegistry collectorRegistry) {
  return PrometheusMeterRegistries.newRegistry(collectorRegistry);
}
 

@Test
public void aggregationAfterGC() throws Exception {
    final MockCache cache1 = new MockCache(1, 2, 3, 4, 5);
    Object cache2 = new MockLoadingCache(6, 7, 8, 9, 10, 11, 12, 13);
    final MeterRegistry registry = PrometheusMeterRegistries.newRegistry();
    final AtomicLong ticker = new AtomicLong();
    final MeterIdPrefix idPrefix = new MeterIdPrefix("baz");

    // Register two caches at the same meter ID.
    CaffeineMetricSupport.setup(registry, idPrefix, cache1, ticker::get);
    CaffeineMetricSupport.setup(registry, idPrefix, (Cache<?, ?>) cache2, ticker::get);

    assertThat(MoreMeters.measureAll(registry))
            .containsEntry("baz.requests#count{result=hit}", 7.0)
            .containsEntry("baz.requests#count{result=miss}", 9.0)
            .containsEntry("baz.loads#count{result=success}", 8.0)
            .containsEntry("baz.loads#count{result=failure}", 9.0)
            .containsEntry("baz.load.duration#count", 10.0)
            .containsEntry("baz.evictions#count", 14.0)
            .containsEntry("baz.eviction.weight#count", 16.0)
            .containsEntry("baz.estimated.size#value", 18.0);

    ticker.addAndGet(CaffeineMetricSupport.UPDATE_INTERVAL_NANOS);

    // Ensure the weak reference which held the cache is cleaned up.
    cache2 = new WeakReference<>(cache2);
    System.gc();
    Thread.sleep(1000);
    assertThat(((Reference<?>) cache2).get()).isNull();

    // Check if the counters are not decreased after the second cache is GC'd.
    assertThat(MoreMeters.measureAll(registry))
            .containsEntry("baz.requests#count{result=hit}", 7.0)
            .containsEntry("baz.requests#count{result=miss}", 9.0)
            .containsEntry("baz.loads#count{result=success}", 8.0)
            .containsEntry("baz.loads#count{result=failure}", 9.0)
            .containsEntry("baz.load.duration#count", 10.0)
            .containsEntry("baz.evictions#count", 14.0)
            .containsEntry("baz.eviction.weight#count", 16.0)
            .containsEntry("baz.estimated.size#value", 5.0); // .. except 'estimatedSize' which is a gauge
}
 

private void doStart() throws Exception {
    boolean success = false;
    ExecutorService repositoryWorker = null;
    ScheduledExecutorService purgeWorker = null;
    ProjectManager pm = null;
    CommandExecutor executor = null;
    PrometheusMeterRegistry meterRegistry = null;
    Server server = null;
    SessionManager sessionManager = null;
    try {
        meterRegistry = PrometheusMeterRegistries.newRegistry();

        logger.info("Starting the Central Dogma ..");
        final ThreadPoolExecutor repositoryWorkerImpl = new ThreadPoolExecutor(
                cfg.numRepositoryWorkers(), cfg.numRepositoryWorkers(),
                60, TimeUnit.SECONDS, new LinkedTransferQueue<>(),
                new DefaultThreadFactory("repository-worker", true));
        repositoryWorkerImpl.allowCoreThreadTimeOut(true);
        repositoryWorker = ExecutorServiceMetrics.monitor(meterRegistry, repositoryWorkerImpl,
                                                          "repositoryWorker");

        logger.info("Starting the project manager: {}", cfg.dataDir());

        purgeWorker = Executors.newSingleThreadScheduledExecutor(
                new DefaultThreadFactory("purge-worker", true));

        pm = new DefaultProjectManager(cfg.dataDir(), repositoryWorker, purgeWorker,
                                       meterRegistry, cfg.repositoryCacheSpec());

        logger.info("Started the project manager: {}", pm);

        logger.info("Current settings:\n{}", cfg);

        sessionManager = initializeSessionManager();

        logger.info("Starting the command executor ..");
        executor = startCommandExecutor(pm, repositoryWorker, purgeWorker,
                                        meterRegistry, sessionManager);
        if (executor.isWritable()) {
            logger.info("Started the command executor.");

            initializeInternalProject(executor);

            // Migrate tokens and create metadata files if it does not exist.
            MigrationUtil.migrate(pm, executor);
        }

        logger.info("Starting the RPC server.");
        server = startServer(pm, executor, meterRegistry, sessionManager);
        logger.info("Started the RPC server at: {}", server.activePorts());
        logger.info("Started the Central Dogma successfully.");
        success = true;
    } finally {
        if (success) {
            this.repositoryWorker = repositoryWorker;
            this.purgeWorker = purgeWorker;
            this.pm = pm;
            this.executor = executor;
            this.meterRegistry = meterRegistry;
            this.server = server;
            this.sessionManager = sessionManager;
        } else {
            doStop(server, executor, pm, repositoryWorker, purgeWorker, sessionManager);
        }
    }
}