GH-823 Add initial support for Observability

spring-cloud-function-context/src/test/java/org/springframework/cloud/function/context/catalog/observability/ObservationFunctionAroundWrapperIntegrationTests.java

@@ -0,0 +1,129 @@
+/*
+ * Copyright 2019-2019 the original author or authors.
+ *
+ * Licensed 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
+ *
+ *      https://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.springframework.cloud.function.context.catalog.observability;
+
+import java.util.Collections;
+import java.util.Deque;
+import java.util.List;
+import java.util.function.BiConsumer;
+import java.util.function.Function;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import io.micrometer.api.instrument.observation.ObservationHandler;
+import io.micrometer.api.instrument.simple.SimpleMeterRegistry;
+import io.micrometer.tracing.Span;
+import io.micrometer.tracing.TraceContext;
+import io.micrometer.tracing.Tracer;
+import io.micrometer.tracing.exporter.FinishedSpan;
+import io.micrometer.tracing.propagation.Propagator;
+import io.micrometer.tracing.test.SampleTestRunner;
+import io.micrometer.tracing.test.reporter.BuildingBlocks;
+import io.micrometer.tracing.test.simple.SpanAssert;
+import io.micrometer.tracing.test.simple.SpansAssert;
+
+import org.springframework.cloud.function.context.FunctionRegistration;
+import org.springframework.cloud.function.context.catalog.FunctionTypeUtils;
+import org.springframework.cloud.function.context.catalog.SimpleFunctionRegistry;
+import org.springframework.cloud.function.context.catalog.observability.tracing.FunctionTracingObservationHandler;
+import org.springframework.cloud.function.context.catalog.observability.tracing.MessageHeaderPropagatorGetter;
+import org.springframework.cloud.function.context.catalog.observability.tracing.MessageHeaderPropagatorSetter;
+import org.springframework.cloud.function.context.config.JsonMessageConverter;
+import org.springframework.cloud.function.json.JacksonMapper;
+import org.springframework.core.convert.support.DefaultConversionService;
+import org.springframework.messaging.Message;
+import org.springframework.messaging.converter.CompositeMessageConverter;
+import org.springframework.messaging.support.MessageBuilder;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class ObservationFunctionAroundWrapperIntegrationTests extends SampleTestRunner {
+
+	CompositeMessageConverter messageConverter = new CompositeMessageConverter(
+		Collections.singletonList(new JsonMessageConverter(new JacksonMapper(new ObjectMapper()))));
+
+	SimpleFunctionRegistry catalog = new SimpleFunctionRegistry(new DefaultConversionService(), messageConverter,
+		new JacksonMapper(new ObjectMapper()));
+
+	ObservationFunctionAroundWrapperIntegrationTests() {
+		super(SampleRunnerConfig.builder().build(), new SimpleMeterRegistry().withTimerObservationHandler());
+	}
+
+	@Override
+	public BiConsumer<BuildingBlocks, Deque<ObservationHandler>> customizeObservationHandlers() {
+		return (buildingBlocks, observationHandlers) -> observationHandlers.addFirst(new FunctionTracingObservationHandler(buildingBlocks.getTracer(), testPropagator(buildingBlocks.getTracer()), new MessageHeaderPropagatorGetter(), new MessageHeaderPropagatorSetter()));
+	}
+
+	private Propagator testPropagator(Tracer tracer) {
+		return new Propagator() {
+
+			@Override
+			public <C> void inject(TraceContext context, C carrier, Setter<C> setter) {
+				setter.set(carrier, "superHeader", "test");
+			}
+
+			@Override
+			public List<String> fields() {
+				return Collections.singletonList("superHeader");
+			}
+
+			@Override
+			public <C> Span.Builder extract(C carrier, Getter<C> getter) {
+				return tracer.spanBuilder();
+			}
+		};
+	}
+
+	@Override
+	public SampleTestRunnerConsumer yourCode() throws Exception {
+		return (buildingBlocks, meterRegistry) -> {
+			ObservationFunctionAroundWrapper wrapper = new ObservationFunctionAroundWrapper(meterRegistry);
+
+			// TESTS
+
+			test_tracing_with_function(wrapper, buildingBlocks);
+		};
+	}
+
+	private void test_tracing_with_function(ObservationFunctionAroundWrapper wrapper, BuildingBlocks bb) {
+		FunctionRegistration<GreeterFunction> registration = new FunctionRegistration<>(new GreeterFunction(),
+			"greeter").type(FunctionTypeUtils.discoverFunctionTypeFromClass(GreeterFunction.class));
+		catalog.register(registration);
+		SimpleFunctionRegistry.FunctionInvocationWrapper function = catalog.lookup("greeter");
+
+		Message<?> result = (Message<?>) wrapper
+			.apply(MessageBuilder.withPayload("hello").setHeader("superHeader", "someValue").build(), function);
+
+		assertThat(result.getPayload()).isEqualTo("HELLO");
+		List<FinishedSpan> spans = bb.getFinishedSpans();
+		SpansAssert.assertThat(spans)
+			.haveSameTraceId()
+			.hasSize(3);
+		SpanAssert.assertThat(spans.get(0)).hasNameEqualTo("handle").isStarted();
+		SpanAssert.assertThat(spans.get(1)).hasNameEqualTo("greeter").isStarted();
+		SpanAssert.assertThat(spans.get(2)).hasNameEqualTo("send").isStarted();
+	}
+
+
+	private static class GreeterFunction implements Function<String, String> {
+
+		@Override
+		public String apply(String in) {
+			return in.toUpperCase();
+		}
+
+	}
+}