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commit df1a1de159b842135b313740a97609b48f1f73e7 Author: Pasquale Congiusti <[email protected]> AuthorDate: Fri Oct 30 09:27:56 2026 +0100 feat(micrometer): don't lookup at every exchange done Enhance the logic to avoid a linear lookup at every exchange call Closes CAMEL-26415 --- .../MicrometerExchangeEventNotifier.java | 21 ++-- ...eterExchangeEventNotifierLastTimestampTest.java | 121 +++++++++++++++++++++ 2 files changed, 131 insertions(+), 11 deletions(-) diff --git a/components/camel-micrometer/src/main/java/org/apache/camel/component/micrometer/eventnotifier/MicrometerExchangeEventNotifier.java b/components/camel-micrometer/src/main/java/org/apache/camel/component/micrometer/eventnotifier/MicrometerExchangeEventNotifier.java index 01939f952477..07814fbe2709 100644 --- a/components/camel-micrometer/src/main/java/org/apache/camel/component/micrometer/eventnotifier/MicrometerExchangeEventNotifier.java +++ b/components/camel-micrometer/src/main/java/org/apache/camel/component/micrometer/eventnotifier/MicrometerExchangeEventNotifier.java @@ -42,7 +42,7 @@ import org.apache.camel.support.SimpleEventNotifierSupport; public class MicrometerExchangeEventNotifier extends AbstractMicrometerEventNotifier<ExchangeEvent> { // Used as a backing value for the camel exchange last timestamp meter - private static AtomicLong lastExchangeTimestampHolder = new AtomicLong(0); + private final AtomicLong lastExchangeTimestampHolder = new AtomicLong(0); private InflightRepository inflightRepository; @@ -100,6 +100,14 @@ public class MicrometerExchangeEventNotifier extends AbstractMicrometerEventNoti inflightRepository = getCamelContext().getInflightRepository(); + // Register once at startup — backing value updated via AtomicLong on each exchange + Gauge.builder( + MicrometerConstants.CAMEL_EXCHANGE_LAST_TIME_METER_NAME, + lastExchangeTimestampHolder, + AtomicLong::get) + .description("Last exchange processed time in milliseconds since the Unix epoch") + .register(getMeterRegistry()); + // need to be able to add/remove meter accordingly to route changes getCamelContext().getManagementStrategy().addEventNotifier(new SimpleEventNotifierSupport() { @Override @@ -215,16 +223,7 @@ public class MicrometerExchangeEventNotifier extends AbstractMicrometerEventNoti } private void setLastTimeExchange() { - Gauge meter = getMeterRegistry().find(MicrometerConstants.CAMEL_EXCHANGE_LAST_TIME_METER_NAME).gauge(); - if (meter == null) { - meter = Gauge.builder( - MicrometerConstants.CAMEL_EXCHANGE_LAST_TIME_METER_NAME, - MicrometerExchangeEventNotifier.lastExchangeTimestampHolder, - AtomicLong::get) - .description("Last exchange processed time in milliseconds since the Unix epoch") - .register(getMeterRegistry()); - } - MicrometerExchangeEventNotifier.lastExchangeTimestampHolder.set(System.currentTimeMillis()); + lastExchangeTimestampHolder.set(System.currentTimeMillis()); } } diff --git a/components/camel-micrometer/src/test/java/org/apache/camel/component/micrometer/eventnotifier/MicrometerExchangeEventNotifierLastTimestampTest.java b/components/camel-micrometer/src/test/java/org/apache/camel/component/micrometer/eventnotifier/MicrometerExchangeEventNotifierLastTimestampTest.java new file mode 100644 index 000000000000..477d08c43888 --- /dev/null +++ b/components/camel-micrometer/src/test/java/org/apache/camel/component/micrometer/eventnotifier/MicrometerExchangeEventNotifierLastTimestampTest.java @@ -0,0 +1,121 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package org.apache.camel.component.micrometer.eventnotifier; + +import java.util.concurrent.atomic.AtomicInteger; + +import io.micrometer.core.instrument.Gauge; +import io.micrometer.core.instrument.search.RequiredSearch; +import io.micrometer.core.instrument.simple.SimpleMeterRegistry; +import org.apache.camel.builder.RouteBuilder; +import org.apache.camel.component.micrometer.MicrometerConstants; +import org.apache.camel.component.mock.MockEndpoint; +import org.junit.jupiter.api.Test; + +import static org.assertj.core.api.Assertions.assertThat; + +/** + * Proves that the current implementation does not perform a MeterRegistry.find() lookup on every exchange completion via + * setLastTimeExchange(). The test wraps the registry in a counting spy and asserts that after N completed exchanges the + * find() call count is 0 — i.e. the gauge is registered once at startup and never looked up again on the hot path. + */ +public class MicrometerExchangeEventNotifierLastTimestampTest extends AbstractMicrometerEventNotifierTest { + + private static final String DIRECT_IN = "direct://in"; + private static final String MOCK_OUT = "mock://out"; + private static final String ROUTE_ID = "test"; + + /** Counts calls to find(CAMEL_EXCHANGE_LAST_TIME_METER_NAME) made after context startup. */ + private final AtomicInteger findCallsAfterStart = new AtomicInteger(0); + + @Override + public void addRegistry() { + meterRegistry = new CountingCompositeMeterRegistry(findCallsAfterStart); + } + + @Override + protected AbstractMicrometerEventNotifier<?> getEventNotifier() { + return new MicrometerExchangeEventNotifier(); + } + + @Test + public void testLastTimestampGaugeIsNotLookedUpOnEveryExchange() throws Exception { + int count = 5; + MockEndpoint mock = getMockEndpoint(MOCK_OUT); + mock.expectedMessageCount(count); + + // Reset counter after startup so we only measure hot-path lookups + findCallsAfterStart.set(0); + + for (int i = 0; i < count; i++) { + template.sendBody(DIRECT_IN, "msg-" + i); + } + mock.assertIsSatisfied(); + + // The gauge should have been registered once at doStart() — never queried again per exchange. + // With the current implementation this assertion FAILS because find() is called `count` times. + assertThat(findCallsAfterStart.get()) + .as("MeterRegistry.find() for the last-timestamp gauge must not be called on every exchange") + .isEqualTo(0); + + // Sanity: the gauge itself must exist and hold a value > 0 + Gauge gauge = meterRegistry.find(MicrometerConstants.CAMEL_EXCHANGE_LAST_TIME_METER_NAME).gauge(); + assertThat(gauge).as("last-timestamp gauge must be registered").isNotNull(); + assertThat(gauge.value()).as("last-timestamp gauge must hold a non-zero timestamp").isGreaterThan(0); + } + + @Override + protected RouteBuilder createRouteBuilder() { + return new RouteBuilder() { + @Override + public void configure() { + from(DIRECT_IN).routeId(ROUTE_ID).to(MOCK_OUT); + } + }; + } + + // --------------------------------------------------------------------------- + // Spy registry that intercepts find() calls for the last-timestamp meter name + // --------------------------------------------------------------------------- + + private static class CountingCompositeMeterRegistry extends io.micrometer.core.instrument.composite.CompositeMeterRegistry { + + private final AtomicInteger counter; + + CountingCompositeMeterRegistry(AtomicInteger counter) { + super(); + add(new SimpleMeterRegistry()); + this.counter = counter; + } + + @Override + public RequiredSearch get(String name) { + if (MicrometerConstants.CAMEL_EXCHANGE_LAST_TIME_METER_NAME.equals(name)) { + counter.incrementAndGet(); + } + return super.get(name); + } + + @Override + public io.micrometer.core.instrument.search.Search find(String name) { + if (MicrometerConstants.CAMEL_EXCHANGE_LAST_TIME_METER_NAME.equals(name)) { + counter.incrementAndGet(); + } + return super.find(name); + } + } +}
