fix(metrics): store service name in defaultDimensions to avoid clearing it (#1146)

* fix: store service name in defaultDimensions

* fix: changed behavior also in singleMetric

* chore: unit test

Author: dreamorosi

Diff for: packages/metrics/src/Metrics.ts

@@ -198,8 +198,8 @@ class Metrics extends Utility implements MetricsInterface {
     if (!this.isColdStart()) return;
     const singleMetric = this.singleMetric();
 
-    if (this.dimensions.service) {
-      singleMetric.addDimension('service', this.dimensions.service);
+    if (this.defaultDimensions.service) {
+      singleMetric.setDefaultDimensions({ service: this.defaultDimensions.service });
     }
     if (this.functionName != null) {
       singleMetric.addDimension('function_name', this.functionName);
@@ -475,7 +475,7 @@ class Metrics extends Utility implements MetricsInterface {
       this.getCustomConfigService()?.getServiceName() ||
       this.getEnvVarsService().getServiceName()) as string;
     if (targetService.length > 0) {
-      this.addDimension('service', targetService);
+      this.setDefaultDimensions({ service: targetService });
     }
   }
 

Diff for: packages/metrics/tests/unit/middleware/middy.test.ts

@@ -247,14 +247,14 @@ describe('Middy middleware', () => {
             CloudWatchMetrics: [
               {
                 Namespace: 'serverlessAirline',
-                Dimensions: [[ 'environment', 'aws_region', 'service', 'function_name' ]],
+                Dimensions: [[ 'service', 'environment', 'aws_region', 'function_name' ]],
                 Metrics: [{ Name: 'ColdStart', Unit: 'Count' }],
               },
             ],
           },
+          service: 'orders',
           environment: 'prod',
           aws_region: 'eu-west-1',
-          service: 'orders',
           function_name: 'foo-bar-function',
           ColdStart: 1,
         })
@@ -267,14 +267,14 @@ describe('Middy middleware', () => {
             CloudWatchMetrics: [
               {
                 Namespace: 'serverlessAirline',
-                Dimensions: [[ 'environment', 'aws_region', 'service' ]],
+                Dimensions: [[ 'service', 'environment', 'aws_region' ]],
                 Metrics: [{ Name: 'successfulBooking', Unit: 'Count' }],
               },
             ],
           },
+          service: 'orders',
           environment: 'prod',
           aws_region: 'eu-west-1',
-          service: 'orders',
           successfulBooking: 1,
         })
       );