feat: add support for custom counter increment value

Author: netanelavr

README.md

@@ -133,6 +133,12 @@ export class UserService {
                user_type: 'standard'
           } );
 
+          // Increment counter with custom value
+          ReporterService.counter( 'batch_users_created_total', {
+               source: 'batch',
+               user_type: 'standard'
+          }, 5 );
+          
           // Update active user gauge
           ReporterService.gauge( 'active_users', 42, {
                region: 'us-east-1'
@@ -152,7 +158,7 @@ The global static service for reporting metrics:
 
 | Method          | Description                 | Parameters                                                  |
 |-----------------|-----------------------------|-------------------------------------------------------------|
-| `counter()`     | Increment a counter metric  | `key: string, labels?: Record<string, string \| number>`                          
+| `counter()`     | Increment a counter metric  | `key: string, labels?: Record<string, string \| number>, value?: number = 1`                          
 | `gauge()`       | Set a gauge value           | `key: string, value: number, labels?: Record<string, string \| number>`           
 | `histogram()`   | Record a histogram value    | `key: string, value: number, labels?: Record<string, string \| number>, buckets?: number[]` 
 | `summary()`     | Record a summary value      | `key: string, value: number, labels?: Record<string, string \| number>, percentiles?: number[]`

src/metrics/metrics.service.spec.ts

@@ -126,6 +126,25 @@ describe( 'MetricsService', () => {
 				service.incCounter( 'test_counter', { '': 'invalid' } );
 			} ).toThrow();
 		} );
+
+		it( 'should increment counter with custom value', async () => {
+			service.incCounter( 'test_counter', {}, 5 );
+			const metrics = await registry.metrics();
+			expect( metrics ).toContain( 'test_counter 5' );
+		} );
+
+		it( 'should increment counter with custom value and labels', async () => {
+			service.incCounter( 'test_counter', { method: 'GET' }, 3 );
+			const metrics = await registry.metrics();
+			expect( metrics ).toContain( 'test_counter{method="GET"} 3' );
+		} );
+
+		it( 'should accumulate custom values correctly', async () => {
+			service.incCounter( 'test_counter', { method: 'GET' }, 3 );
+			service.incCounter( 'test_counter', { method: 'GET' }, 2 );
+			const metrics = await registry.metrics();
+			expect( metrics ).toContain( 'test_counter{method="GET"} 5' );
+		} );
 	} );
 
 	describe( 'setGauge', () => {

src/metrics/metrics.service.ts

@@ -25,7 +25,7 @@ export class MetricsService {
 		}
 	}
 
-	public incCounter( key: string, labels?: Record<string, string | number> ): void {
+	public incCounter( key: string, labels?: Record<string, string | number>, value: number = 1 ): void {
 		if ( ! this.counter[ key ] ) {
 			this.counter[ key ] = new Counter( {
 				name: key,
@@ -34,7 +34,7 @@ export class MetricsService {
 				registers: [ this.registry ],
 			} );
 		}
-		this.counter[ key ].inc( labels || {} );
+		this.counter[ key ].inc( labels || {}, value );
 	}
 
 	public setGauge( key: string, value: number, labels?: Record<string, string | number> ): void {

src/reporter/reporter.service.spec.ts

@@ -70,6 +70,25 @@ describe( 'ReporterService', () => {
 			const metrics = await registry.metrics();
 			expect( metrics ).toContain( 'test_counter 1' );
 		} );
+
+		it( 'should increment counter with custom value', async () => {
+			ReporterService.counter( 'test_counter', undefined, 5 );
+			const metrics = await registry.metrics();
+			expect( metrics ).toContain( 'test_counter 5' );
+		} );
+
+		it( 'should increment counter with custom value and labels', async () => {
+			ReporterService.counter( 'test_counter', { method: 'POST' }, 3 );
+			const metrics = await registry.metrics();
+			expect( metrics ).toContain( 'test_counter{method="POST"} 3' );
+		} );
+
+		it( 'should accumulate custom values correctly', async () => {
+			ReporterService.counter( 'test_counter', { method: 'POST' }, 3 );
+			ReporterService.counter( 'test_counter', { method: 'POST' }, 2 );
+			const metrics = await registry.metrics();
+			expect( metrics ).toContain( 'test_counter{method="POST"} 5' );
+		} );
 	} );
 
 	describe( 'gauge', () => {

src/reporter/reporter.service.ts

@@ -12,9 +12,9 @@ export class ReporterService implements OnApplicationBootstrap {
 		ReporterService.metricsService = this.metrics;
 	}
 
-	static counter( key: string, labels?: Record<string, string | number> ): void {
+	static counter( key: string, labels?: Record<string, string | number>, value: number = 1 ): void {
 		try {
-			ReporterService.metricsService.incCounter( key, labels );
+			ReporterService.metricsService.incCounter( key, labels, value );
 		} catch ( error ) {
 			this.logError( 'increment counter', key, labels, error );
 		}