feat(metric): add logic, unit tests for the middy middleware

Author: saragerion

packages/metrics/.eslintrc.json

@@ -37,6 +37,7 @@
   "typedocMain": "src/index.ts",
   "devDependencies": {
     "@commitlint/cli": "^15.0.0",
+    "@middy/core": "^2.5.3",
     "@types/aws-lambda": "^8.10.72",
     "@types/jest": "^27.0.0",
     "@types/node": "^16.6.0",

packages/metrics/lerna

@@ -1,12 +1,12 @@
 import { MetricsInterface } from '.';
 import { ConfigServiceInterface, EnvironmentVariablesService } from './config';
 import {
-  DecoratorOptions,
+  MetricsOptions,
   Dimensions,
   EmfOutput,
   HandlerMethodDecorator,
   StoredMetrics,
-  MetricsOptions,
+  ExtraOptions,
   MetricUnit,
   MetricUnits,
 } from './types';
@@ -165,7 +165,6 @@ class Metrics implements MetricsInterface {
     this.storedMetrics = {};
   }
 
-
   /**
    * Throw an Error if the metrics buffer is empty.
    *
@@ -212,7 +211,7 @@ class Metrics implements MetricsInterface {
    *
    * @decorator Class
    */
-  public logMetrics(options: DecoratorOptions = {}): HandlerMethodDecorator {
+  public logMetrics(options: ExtraOptions = {}): HandlerMethodDecorator {
     const { raiseOnEmptyMetrics, defaultDimensions, captureColdStartMetric } = options;
     if (raiseOnEmptyMetrics) {
       this.raiseOnEmptyMetrics();
@@ -228,7 +227,8 @@ class Metrics implements MetricsInterface {
 
         if (captureColdStartMetric) this.captureColdStartMetric();
         try {
-          const result = originalMethod?.apply(this, [event, context, callback]);
+          const result = originalMethod?.apply(this, [ event, context, callback ]);
+          
           return result;
         } finally {
           this.purgeStoredMetrics();
@@ -284,7 +284,7 @@ class Metrics implements MetricsInterface {
       {},
     );
 
-    const dimensionNames = [...Object.keys(this.defaultDimensions), ...Object.keys(this.dimensions)];
+    const dimensionNames = [ ...Object.keys(this.defaultDimensions), ...Object.keys(this.dimensions) ];
 
     return {
       _aws: {
@@ -334,6 +334,7 @@ class Metrics implements MetricsInterface {
     return new Metrics({
       namespace: this.namespace,
       service: this.dimensions.service,
+      defaultDimensions: this.defaultDimensions,
       singleMetric: true,
     });
   }
@@ -373,6 +374,10 @@ class Metrics implements MetricsInterface {
     singleMetric.addMetric('ColdStart', MetricUnits.Count, 1);
   }
 
+  public setFunctionName(value: string): void {
+    this.functionName = value;
+  }
+
   private getCurrentDimensionsCount(): number {
     return Object.keys(this.dimensions).length + Object.keys(this.defaultDimensions).length;
   }

packages/metrics/package-lock.json

@@ -1,20 +1,20 @@
 import { Metrics } from './Metrics';
-import { MetricUnit, EmfOutput, HandlerMethodDecorator, Dimensions, DecoratorOptions } from './types';
+import { MetricUnit, EmfOutput, HandlerMethodDecorator, Dimensions, MetricsOptions } from './types';
 
 interface MetricsInterface {
-  addDimension(name: string, value: string): void;
-  addDimensions(dimensions: {[key: string]: string}): void;
-  addMetadata(key: string, value: string): void;
-  addMetric(name: string, unit:MetricUnit, value:number): void;
-  clearDimensions(): void;
-  clearMetadata(): void;
-  clearMetrics(): void;
-  clearDefaultDimensions(): void;
-  logMetrics(options?: DecoratorOptions): HandlerMethodDecorator;
-  purgeStoredMetrics(): void;
-  serializeMetrics(): EmfOutput;
-  setDefaultDimensions(dimensions: Dimensions | undefined): void;
-  singleMetric(): Metrics;
+  addDimension(name: string, value: string): void
+  addDimensions(dimensions: {[key: string]: string}): void
+  addMetadata(key: string, value: string): void
+  addMetric(name: string, unit:MetricUnit, value:number): void
+  clearDimensions(): void
+  clearMetadata(): void
+  clearMetrics(): void
+  clearDefaultDimensions(): void
+  logMetrics(options?: MetricsOptions): HandlerMethodDecorator
+  purgeStoredMetrics(): void
+  serializeMetrics(): EmfOutput
+  setDefaultDimensions(dimensions: Dimensions | undefined): void
+  singleMetric(): Metrics
 }
 
 export {

packages/metrics/package.json

@@ -0,0 +1 @@
+export * from './middy';