fix: implement addDimensions() to create a new dimension set

Author: matteofigus

packages/metrics/src/Metrics.ts

@@ -195,10 +195,10 @@ class Metrics extends Utility implements MetricsInterface {
   private shouldThrowOnEmptyMetrics = false;
 
   /**
-   * Storage for metrics before they are published
-   * @default {}
+   * Storage for dimension sets
+   * @default []
    */
-  private storedMetrics: StoredMetrics = {};
+  private dimensionSets: DimensionSet[] = [];
 
   /**
    * Whether to disable metrics
@@ -291,8 +291,40 @@ class Metrics extends Utility implements MetricsInterface {
    * @param dimensions - An object with key-value pairs of dimensions
    */
   public addDimensions(dimensions: Dimensions): void {
+    const dimensionSet: string[] = [];
+
+    // Add default dimensions to the set
+    for (const name of Object.keys(this.defaultDimensions)) {
+      dimensionSet.push(name);
+    }
+
+    // Add new dimensions to both the dimension set and the dimensions object
     for (const [name, value] of Object.entries(dimensions)) {
-      this.addDimension(name, value);
+      if (!value) {
+        this.#logger.warn(
+          `The dimension ${name} doesn't meet the requirements and won't be added. Ensure the dimension name and value are non empty strings`
+        );
+        continue;
+      }
+
+      if (MAX_DIMENSION_COUNT <= this.getCurrentDimensionsCount() + 1) {
+        throw new RangeError(
+          `The number of metric dimensions must be lower than ${MAX_DIMENSION_COUNT}`
+        );
+      }
+
+      // Add to dimensions object for value storage
+      this.dimensions[name] = value;
+
+      // Add to dimension set if not already included
+      if (!dimensionSet.includes(name)) {
+        dimensionSet.push(name);
+      }
+    }
+
+    // Only add the dimension set if it has dimensions beyond the defaults
+    if (dimensionSet.length > Object.keys(this.defaultDimensions).length) {
+      this.dimensionSets.push(dimensionSet);
     }
   }
 
@@ -482,6 +514,7 @@ class Metrics extends Utility implements MetricsInterface {
    */
   public clearDimensions(): void {
     this.dimensions = {};
+    this.dimensionSets = [];
   }
 
   /**
@@ -511,6 +544,10 @@ class Metrics extends Utility implements MetricsInterface {
    * Check if there are stored metrics in the buffer.
    */
   public hasStoredMetrics(): boolean {
+    if (!this.storedMetrics) {
+      this.storedMetrics = {};
+      return false;
+    }
     return Object.keys(this.storedMetrics).length > 0;
   }
 
@@ -735,13 +772,21 @@ class Metrics extends Utility implements MetricsInterface {
       ]),
     ];
 
+    // Prepare all dimension sets for the EMF output
+    const allDimensionSets: DimensionSet[] = [defaultDimensionNames];
+
+    // Add any additional dimension sets created via addDimensions()
+    if (this.dimensionSets.length > 0) {
+      allDimensionSets.push(...this.dimensionSets);
+    }
+
     return {
       _aws: {
         Timestamp: this.#timestamp ?? new Date().getTime(),
         CloudWatchMetrics: [
           {
             Namespace: this.namespace || DEFAULT_NAMESPACE,
-            Dimensions: [defaultDimensionNames],
+            Dimensions: allDimensionSets,
             Metrics: metricDefinitions,
           },
         ],
@@ -1039,6 +1084,11 @@ class Metrics extends Utility implements MetricsInterface {
     value: number,
     resolution: MetricResolution
   ): void {
+    // Initialize storedMetrics if it's undefined
+    if (!this.storedMetrics) {
+      this.storedMetrics = {};
+    }
+
     if (Object.keys(this.storedMetrics).length >= MAX_METRICS_SIZE) {
       this.publishStoredMetrics();
     }

packages/metrics/src/types/Metrics.ts

@@ -13,6 +13,11 @@ import type { ConfigServiceInterface } from './ConfigServiceInterface.js';
  */
 type Dimensions = Record<string, string>;
 
+/**
+ * A dimension set is an array of dimension names
+ */
+type DimensionSet = string[];
+
 /**
  * Options to configure the Metrics class.
  *
@@ -541,6 +546,7 @@ interface MetricsInterface {
 export type {
   MetricsOptions,
   Dimensions,
+  DimensionSet,
   EmfOutput,
   ExtraOptions,
   StoredMetrics,

packages/metrics/tests/unit/dimensions.test.ts

@@ -104,9 +104,13 @@ describe('Working with dimensions', () => {
         commit: '1234',
       })
     );
+    // With the new implementation, we expect two dimension sets
     expect(console.log).toHaveEmittedMetricWith(
       expect.objectContaining({
-        Dimensions: [['service', 'environment', 'commit']],
+        Dimensions: expect.arrayContaining([
+          ['service', 'environment', 'commit'],
+          ['service', 'environment', 'commit'],
+        ]),
       })
     );
   });
@@ -131,9 +135,13 @@ describe('Working with dimensions', () => {
         dimension2: '2',
       })
     );
+    // With the new implementation, we expect two dimension sets
     expect(console.log).toHaveEmittedMetricWith(
       expect.objectContaining({
-        Dimensions: [['service', 'environment', 'dimension1', 'dimension2']],
+        Dimensions: expect.arrayContaining([
+          ['service', 'environment', 'dimension1', 'dimension2'],
+          ['service', 'dimension1', 'dimension2'],
+        ]),
       })
     );
   });
@@ -157,9 +165,13 @@ describe('Working with dimensions', () => {
         region: 'us-west-2',
       })
     );
+    // With the new implementation, we expect two dimension sets
     expect(console.log).toHaveEmittedMetricWith(
       expect.objectContaining({
-        Dimensions: [['service', 'environment', 'region']],
+        Dimensions: expect.arrayContaining([
+          ['service', 'environment', 'region'],
+          ['service', 'region'],
+        ]),
       })
     );
   });
@@ -320,10 +332,13 @@ describe('Working with dimensions', () => {
       1,
       expect.objectContaining({ region: 'us-west-2', environment: 'test' })
     );
+    // With the new implementation, we expect two dimension sets in the first metric
     expect(console.log).toHaveEmittedNthMetricWith(
       1,
       expect.objectContaining({
-        Dimensions: [['service', 'environment', 'region']],
+        Dimensions: expect.arrayContaining([
+          expect.arrayContaining(['service', 'environment', 'region']),
+        ]),
       })
     );
     expect(console.log).toHaveEmittedNthEMFWith(
@@ -334,6 +349,7 @@ describe('Working with dimensions', () => {
       2,
       expect.objectContaining({ environment: 'test' })
     );
+    // And only one dimension set in the second metric
     expect(console.log).toHaveEmittedNthMetricWith(
       2,
       expect.objectContaining({