feat(metrics): introduce MetricsUtils.withMetricsLogger utility (#1000)

feat(metrics): introduce  MetricsUtils.withMetricsLogger utility (#1000)

Author: humanzz

docs/core/metrics.md

@@ -233,4 +233,28 @@ CloudWatch EMF uses the same dimensions across all your metrics. Use `withSingle
             });
         }
     }
-    ```
+    ```
+
+## Creating metrics with different configurations
+
+Use `withMetricsLogger` if you have one or more metrics that should have different configurations e.g. dimensions or namespace.
+
+=== "App.java"
+
+    ```java hl_lines="7 8 9 10 11 12 13" 
+    import static software.amazon.lambda.powertools.metrics.MetricsUtils.withMetricsLogger;
+
+    public class App implements RequestHandler<Object, Object> {
+
+        @Override
+        public Object handleRequest(Object input, Context context) {
+             withMetricsLogger(logger -> {
+                // override default dimensions
+                logger.setDimensions(DimensionSet.of("AnotherService", "CustomService"));
+                // add metrics
+                logger.putMetric("CustomMetrics1", 1, Unit.COUNT);
+                logger.putMetric("CustomMetrics2", 5, Unit.COUNT);
+            });
+        }
+    }
+    ```

powertools-metrics/src/main/java/software/amazon/lambda/powertools/metrics/MetricsUtils.java

@@ -81,16 +81,10 @@ public static void withSingleMetric(final String name,
                                         final double value,
                                         final Unit unit,
                                         final Consumer<MetricsLogger> logger) {
-        MetricsLogger metricsLogger = logger();
-
-        try {
-            metricsLogger.setNamespace(defaultNameSpace());
+        withMetricLogger(metricsLogger -> {
             metricsLogger.putMetric(name, value, unit);
-            captureRequestAndTraceId(metricsLogger);
             logger.accept(metricsLogger);
-        } finally {
-            metricsLogger.flush();
-        }
+        });
     }
 
     /**
@@ -109,11 +103,26 @@ public static void withSingleMetric(final String name,
                                         final Unit unit,
                                         final String namespace,
                                         final Consumer<MetricsLogger> logger) {
+        withMetricLogger(metricsLogger -> {
+            metricsLogger.setNamespace(namespace);
+            metricsLogger.putMetric(name, value, unit);
+            logger.accept(metricsLogger);
+        });
+    }
+
+    /**
+     * Provide and immediately flush a {@link MetricsLogger}. It uses the default namespace
+     * specified either on {@link Metrics} annotation or via POWERTOOLS_METRICS_NAMESPACE env var.
+     * It by default captures function_request_id as property if used together with {@link Metrics} annotation. It will also
+     * capture xray_trace_id as property if tracing is enabled.
+     *
+     * @param logger the MetricsLogger
+     */
+    public static void withMetricLogger(final Consumer<MetricsLogger> logger) {
         MetricsLogger metricsLogger = logger();
 
         try {
-            metricsLogger.setNamespace(namespace);
-            metricsLogger.putMetric(name, value, unit);
+            metricsLogger.setNamespace(defaultNameSpace());
             captureRequestAndTraceId(metricsLogger);
             logger.accept(metricsLogger);
         } finally {

powertools-metrics/src/test/java/software/amazon/lambda/powertools/metrics/MetricsLoggerTest.java

@@ -6,7 +6,6 @@
 
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
-import org.assertj.core.api.Assertions;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.BeforeEach;
@@ -16,9 +15,9 @@
 import software.amazon.cloudwatchlogs.emf.model.DimensionSet;
 import software.amazon.cloudwatchlogs.emf.model.Unit;
 
-import static java.util.Collections.*;
-import static org.assertj.core.api.Assertions.*;
+import static java.util.Collections.emptyMap;
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatNullPointerException;
 import static org.mockito.Mockito.mockStatic;
 import static software.amazon.lambda.powertools.core.internal.SystemWrapper.getenv;
 
@@ -123,6 +122,38 @@ void singleMetricsCaptureUtilityWithDefaultNameSpace() {
         }
     }
 
+    @Test
+    void metricsLoggerCaptureUtilityWithDefaultNameSpace() {
+        try (MockedStatic<SystemWrapper> mocked = mockStatic(SystemWrapper.class);
+             MockedStatic<software.amazon.lambda.powertools.core.internal.SystemWrapper> internalWrapper = mockStatic(software.amazon.lambda.powertools.core.internal.SystemWrapper.class)) {
+            mocked.when(() -> SystemWrapper.getenv("AWS_EMF_ENVIRONMENT")).thenReturn("Lambda");
+            mocked.when(() -> SystemWrapper.getenv("POWERTOOLS_METRICS_NAMESPACE")).thenReturn("GlobalName");
+            internalWrapper.when(() -> getenv("_X_AMZN_TRACE_ID")).thenReturn("Root=1-5759e988-bd862e3fe1be46a994272793;Parent=53995c3f42cd8ad8;Sampled=1\"");
+
+            MetricsUtils.withMetricLogger(metricsLogger -> {
+                metricsLogger.setDimensions(DimensionSet.of("Dimension1", "Value1"));
+                metricsLogger.putMetric("Metric1", 1, Unit.COUNT);
+            });
+
+            assertThat(out.toString())
+                    .satisfies(s -> {
+                        Map<String, Object> logAsJson = readAsJson(s);
+
+                        assertThat(logAsJson)
+                                .containsEntry("Metric1", 1.0)
+                                .containsEntry("Dimension1", "Value1")
+                                .containsKey("_aws")
+                                .containsEntry("xray_trace_id", "1-5759e988-bd862e3fe1be46a994272793");
+
+                        Map<String, Object> aws = (Map<String, Object>) logAsJson.get("_aws");
+
+                        assertThat(aws.get("CloudWatchMetrics"))
+                                .asString()
+                                .contains("Namespace=GlobalName");
+                    });
+        }
+    }
+
     @Test
     void shouldThrowExceptionWhenDefaultDimensionIsNull() {
         assertThatNullPointerException()