feat(metrics): logMetrics middleware (#338)

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

* chore(metrics): lint changes

* docs(metrics): logMetric middleware and examples

* test(metrics): add array input for middleware

* Update packages/metrics/package.json

Co-authored-by: Andrea Amorosi <dreamorosi@gmail.com>

* Update docs/core/metrics.md

Co-authored-by: ijemmy <ijemmy@users.noreply.github.com>

* Update docs/core/metrics.md

Co-authored-by: ijemmy <ijemmy@users.noreply.github.com>

* Update docs/core/metrics.md

Co-authored-by: ijemmy <ijemmy@users.noreply.github.com>

* Update docs/core/metrics.md

Co-authored-by: ijemmy <ijemmy@users.noreply.github.com>

* improv(metrics): improve docs, examples, naming

* Update packages/metrics/examples/decorator/default-dimensions.ts

Co-authored-by: ijemmy <ijemmy@users.noreply.github.com>

* Update packages/metrics/examples/decorator/empty-metrics.ts

Co-authored-by: ijemmy <ijemmy@users.noreply.github.com>

* Update docs/core/metrics.md

Co-authored-by: Florian Chazal <florianchazal@gmail.com>

* Update docs/core/metrics.md

Co-authored-by: Florian Chazal <florianchazal@gmail.com>

* Update docs/core/metrics.md

Co-authored-by: Florian Chazal <florianchazal@gmail.com>

* Update docs/core/metrics.md

Co-authored-by: Florian Chazal <florianchazal@gmail.com>

* Update docs/core/metrics.md

Co-authored-by: Florian Chazal <florianchazal@gmail.com>

* Update packages/metrics/examples/decorator/manual-flushing.ts

Co-authored-by: ijemmy <ijemmy@users.noreply.github.com>

* improv(metrics): logMetricsAfterOrError middleware, examples update

* improv(metrics): logMetricsAfterOrError middleware, examples update

* improv(metrics): logMetricsAfterOrError middleware, examples update

* tests(metrics): fix handlers type

* fix(metrics): examples file path

* revert(metrics): jest groups

* chore(metrics): rename examples script, prepending 'decorator'

* fix(metrics): removed empty lint file

* ci(all): exclude examples CDK for linting

* chore(all): lint fix for CDK examples

* test(metrics): added metrics middleware jest group

Co-authored-by: Andrea Amorosi <dreamorosi@gmail.com>
Co-authored-by: ijemmy <ijemmy@users.noreply.github.com>
Co-authored-by: Florian Chazal <florianchazal@gmail.com>

Author: 4 people

docs/core/metrics.md

@@ -24,7 +24,7 @@ Metrics has two global settings that will be used across all metrics emitted:
 
 |Setting|Description|Environment Variable|Constructor Parameter|
 |---|---|---|---|
-|Metric namespace|Logical container where all metrics will be placed e.g. ServerlessAirline|POWERTOOLS_METRICS_NAMESPACE|namespace|
+|Metric namespace|Logical container where all metrics will be placed e.g. serverlessAirline|POWERTOOLS_METRICS_NAMESPACE|namespace|
 |Service|Optionally, sets service metric dimension across all metrics e.g. payment|POWERTOOLS_SERVICE_NAME|service|
 
 ```typescript

packages/metrics/.eslintrc.json

@@ -1,9 +1,9 @@
 import * as dummyEvent from '../../../tests/resources/events/custom/hello-world.json';
 import { context as dummyContext } from '../../../tests/resources/contexts/hello-world';
-import { LambdaInterface } from './utils/lambda/LambdaInterface';
 import { populateEnvironmentVariables } from '../tests/helpers';
-import { Callback, Context } from 'aws-lambda/handler';
 import { Metrics, MetricUnits } from '../src';
+import middy from '@middy/core';
+import { logMetrics } from '../src/middleware/middy';
 
 // Populate runtime
 populateEnvironmentVariables();
@@ -12,15 +12,15 @@ process.env.POWERTOOLS_METRICS_NAMESPACE = 'hello-world';
 
 const metrics = new Metrics();
 
-class Lambda implements LambdaInterface {
+const lambdaHandler = async (): Promise<void> => {
 
-  @metrics.logMetrics({ captureColdStartMetric: true })
-  public handler<TEvent, TResult>(_event: TEvent, _context: Context, _callback: Callback<TResult>): void | Promise<TResult> {
-    metrics.addDimension('OuterDimension', 'true');
-    metrics.addMetric('test-metric', MetricUnits.Count, 10);
-  }
+  metrics.addDimension('custom-dimension', 'true');
+  metrics.addMetric('test-metric', MetricUnits.Count, 10);
 
-}
+};
 
-new Lambda().handler(dummyEvent, dummyContext, () => console.log('Lambda invoked!'));
-new Lambda().handler(dummyEvent, dummyContext, () => console.log('Lambda invoked again!'));
+const handlerWithMiddleware = middy(lambdaHandler)
+  .use(logMetrics(metrics, { captureColdStartMetric: true }));
+
+handlerWithMiddleware(dummyEvent, dummyContext, () => console.log('Lambda invoked!'));
+handlerWithMiddleware(dummyEvent, dummyContext, () => console.log('Lambda invoked again!'));

packages/metrics/README.md

@@ -1,21 +1,25 @@
 import * as dummyEvent from '../../../tests/resources/events/custom/hello-world.json';
 import { context as dummyContext } from '../../../tests/resources/contexts/hello-world';
+import { populateEnvironmentVariables } from '../tests/helpers';
 import { Metrics, MetricUnits } from '../src';
-import { LambdaInterface } from "./utils/lambda";
-import { Callback, Context } from "aws-lambda/handler";
+import middy from '@middy/core';
+import { logMetrics } from '../src/middleware/middy';
+
+// Populate runtime
+populateEnvironmentVariables();
+// Additional runtime variables
+process.env.POWERTOOLS_METRICS_NAMESPACE = 'hello-world';
 
 const metrics = new Metrics({
   namespace: 'hello-world-constructor',
   service: 'hello-world-service-constructor'
 });
 
-class Lambda implements LambdaInterface {
-
-  @metrics.logMetrics()
-  public handler<TEvent, TResult>(_event: TEvent, _context: Context, _callback: Callback<TResult>): void | Promise<TResult> {
-    metrics.addMetric('test-metric', MetricUnits.Count, 10);
+const lambdaHandler = async (): Promise<void> => {
+  metrics.addMetric('test-metric', MetricUnits.Count, 10);
+};
 
-  }
+const handlerWithMiddleware = middy(lambdaHandler)
+  .use(logMetrics(metrics));
 
-}
-new Lambda().handler(dummyEvent, dummyContext, () => console.log('Lambda invoked!'));
+handlerWithMiddleware(dummyEvent, dummyContext, () => console.log('Lambda invoked!'));

packages/metrics/examples/cold-start.ts

@@ -0,0 +1,26 @@
+import * as dummyEvent from '../../../../tests/resources/events/custom/hello-world.json';
+import { context as dummyContext } from '../../../../tests/resources/contexts/hello-world';
+import { LambdaInterface } from './../utils/lambda/LambdaInterface';
+import { populateEnvironmentVariables } from '../../tests/helpers';
+import { Callback, Context } from 'aws-lambda/handler';
+import { Metrics, MetricUnits } from '../../src';
+
+// Populate runtime
+populateEnvironmentVariables();
+// Additional runtime variables
+process.env.POWERTOOLS_METRICS_NAMESPACE = 'hello-world';
+
+const metrics = new Metrics();
+
+class Lambda implements LambdaInterface {
+
+  @metrics.logMetrics({ captureColdStartMetric: true })
+  public handler<TEvent, TResult>(_event: TEvent, _context: Context, _callback: Callback<TResult>): void | Promise<TResult> {
+    metrics.addDimension('OuterDimension', 'true');
+    metrics.addMetric('test-metric', MetricUnits.Count, 10);
+  }
+
+}
+
+new Lambda().handler(dummyEvent, dummyContext, () => console.log('Lambda invoked!'));
+new Lambda().handler(dummyEvent, dummyContext, () => console.log('Lambda invoked again!'));

packages/metrics/examples/constructor-options.ts

@@ -0,0 +1,21 @@
+import * as dummyEvent from '../../../../tests/resources/events/custom/hello-world.json';
+import { context as dummyContext } from '../../../../tests/resources/contexts/hello-world';
+import { Metrics, MetricUnits } from '../../src';
+import { LambdaInterface } from './../utils/lambda';
+import { Callback, Context } from 'aws-lambda/handler';
+
+const metrics = new Metrics({
+  namespace: 'hello-world-constructor',
+  service: 'hello-world-service-constructor'
+});
+
+class Lambda implements LambdaInterface {
+
+  @metrics.logMetrics()
+  public handler<TEvent, TResult>(_event: TEvent, _context: Context, _callback: Callback<TResult>): void | Promise<TResult> {
+    metrics.addMetric('test-metric', MetricUnits.Count, 10);
+
+  }
+
+}
+new Lambda().handler(dummyEvent, dummyContext, () => console.log('Lambda invoked!'));

packages/metrics/examples/decorator/cold-start.ts

@@ -0,0 +1,27 @@
+import { populateEnvironmentVariables } from '../../tests/helpers';
+
+// Populate runtime
+populateEnvironmentVariables();
+// Additional runtime variables
+process.env.POWERTOOLS_METRICS_NAMESPACE = 'hello-world-constructor';
+process.env.POWERTOOLS_SERVICE_NAME = 'hello-world-service-constructor';
+
+import * as dummyEvent from '../../../tests/resources/events/custom/hello-world.json';
+import { context as dummyContext } from '../../../tests/resources/contexts/hello-world';
+import { LambdaInterface } from './utils/lambda/LambdaInterface';
+import { Callback, Context } from 'aws-lambda/handler';
+import { Metrics, MetricUnits } from '../src';
+
+const metrics = new Metrics({ defaultDimensions:{ 'application': 'hello-world' } });
+
+class Lambda implements LambdaInterface {
+
+  @metrics.logMetrics()
+  public handler<TEvent, TResult>(_event: TEvent, _context: Context, _callback: Callback<TResult>): void | Promise<TResult> {
+    metrics.addMetric('test-metric', MetricUnits.Count, 10);
+
+  }
+
+}
+
+new Lambda().handler(dummyEvent, dummyContext, () => console.log('Lambda invoked!'));