Promisify pushgateway methods

Author: PierrickP

CHANGELOG.md

@@ -14,6 +14,21 @@ project adheres to [Semantic Versioning](http://semver.org/).
   Fewer bucket bounds will be affected by rounding errors. Histogram bucket
   labels may change.
 
+- changed: The push gateway methods `pushAdd()`, `push()` and `delete()` now
+  return Promises instead of accepting a callback:
+
+  ```js
+  // Old:
+  gateway.pushAdd({ jobName: 'test' }, (err, resp, body) => {});
+  // New:
+  gateway
+    .pushAdd({ jobName: 'test' })
+    .then(({ resp, body }) => {})
+    .catch(err => {});
+  // or
+  const { resp, body } = await gateway.pushAdd({ jobName: 'test' });
+  ```
+
 ### Changed
 
 ### Added

README.md

@@ -490,16 +490,36 @@ It is possible to push metrics via a
 const client = require('prom-client');
 let gateway = new client.Pushgateway('http://127.0.0.1:9091');
 
-gateway.pushAdd({ jobName: 'test' }, function (err, resp, body) {}); //Add metric and overwrite old ones
-gateway.push({ jobName: 'test' }, function (err, resp, body) {}); //Overwrite all metrics (use PUT)
-gateway.delete({ jobName: 'test' }, function (err, resp, body) {}); //Delete all metrics for jobName
+gateway.pushAdd({ jobName: 'test' })
+	.then({resp, body} => {
+		/* ... */
+	})
+	.catch(err => {
+		/* ... */
+	})); //Add metric and overwrite old ones
+gateway.push({ jobName: 'test' })
+	.then({resp, body} => {
+		/* ... */
+	})
+	.catch(err => {
+		/* ... */
+	})); //Overwrite all metrics (use PUT)
+gateway.delete({ jobName: 'test' })
+	.then({resp, body} => {
+		/* ... */
+	})
+	.catch(err => {
+		/* ... */
+	})); //Delete all metrics for jobName
 
 //All gateway requests can have groupings on it
-gateway.pushAdd({ jobName: 'test', groupings: { key: 'value' } }, function (
-  err,
-  resp,
-  body,
-) {});
+gateway.pushAdd({ jobName: 'test', groupings: { key: 'value' } })
+	.then({resp, body} => {
+		/* ... */
+	})
+	.catch(err => {
+		/* ... */
+	}));
 
 // It's possible to extend the Pushgateway with request options from nodes core
 // http/https library. In particular, you might want to provide an agent so that

example/pushgateway.js

@@ -16,11 +16,15 @@ function run() {
 	register.registerMetric(test);
 	test.inc(10);
 
-	gateway.push({ jobName: prefix }, (err, resp, body) => {
-		console.log(`Error: ${err}`);
-		console.log(`Body: ${body}`);
-		console.log(`Response status: ${resp.statusCode}`);
-	});
+	return gateway
+		.push({ jobName: prefix })
+		.then(({ resp, body }) => {
+			console.log(`Body: ${body}`);
+			console.log(`Response status: ${resp.statusCode}`);
+		})
+		.catch(err => {
+			console.log(`Error: ${err}`);
+		});
 }
 
 run();

lib/pushgateway.js

@@ -15,31 +15,31 @@ class Pushgateway {
 		this.requestOptions = Object.assign({}, options);
 	}
 
-	pushAdd(params, callback) {
+	pushAdd(params) {
 		if (!params || !params.jobName) {
 			throw new Error('Missing jobName parameter');
 		}
 
-		useGateway.call(this, 'POST', params.jobName, params.groupings, callback);
+		return useGateway.call(this, 'POST', params.jobName, params.groupings);
 	}
 
-	push(params, callback) {
+	push(params) {
 		if (!params || !params.jobName) {
 			throw new Error('Missing jobName parameter');
 		}
 
-		useGateway.call(this, 'PUT', params.jobName, params.groupings, callback);
+		return useGateway.call(this, 'PUT', params.jobName, params.groupings);
 	}
 
-	delete(params, callback) {
+	delete(params) {
 		if (!params || !params.jobName) {
 			throw new Error('Missing jobName parameter');
 		}
 
-		useGateway.call(this, 'DELETE', params.jobName, params.groupings, callback);
+		return useGateway.call(this, 'DELETE', params.jobName, params.groupings);
 	}
 }
-function useGateway(method, job, groupings, callback) {
+async function useGateway(method, job, groupings) {
 	// `URL` first added in v6.13.0
 	// eslint-disable-next-line node/no-deprecated-api
 	const gatewayUrlParsed = url.parse(this.gatewayUrl);
@@ -60,34 +60,35 @@ function useGateway(method, job, groupings, callback) {
 		method,
 	});
 
-	const req = httpModule.request(options, res => {
-		let body = '';
-		res.setEncoding('utf8');
-		res.on('data', chunk => {
-			body += chunk;
+	return new Promise((resolve, reject) => {
+		const req = httpModule.request(options, resp => {
+			let body = '';
+			resp.setEncoding('utf8');
+			resp.on('data', chunk => {
+				body += chunk;
+			});
+			resp.on('end', () => {
+				resolve({ resp, body });
+			});
 		});
-		res.on('end', () => {
-			callback(null, res, body);
+		req.on('error', err => {
+			reject(err);
 		});
-	});
-	req.on('error', err => {
-		callback(err);
-	});
 
-	if (method !== 'DELETE') {
-		this.registry
-			.metrics()
-			.then(metrics => {
-				req.write(metrics);
-				req.end();
-			})
-			.catch(err => {
-				req.end();
-				callback(err);
-			});
-	} else {
-		req.end();
-	}
+		if (method !== 'DELETE') {
+			this.registry
+				.metrics()
+				.then(metrics => {
+					req.write(metrics);
+					req.end();
+				})
+				.catch(err => {
+					reject(err);
+				});
+		} else {
+			req.end();
+		}
+	});
 }
 
 function generateGroupings(groupings) {

package.json

@@ -40,6 +40,7 @@
 		"husky": "^4.2.1",
 		"jest": "^26.0.1",
 		"lint-staged": "^10.0.4",
+		"nock": "^13.0.5",
 		"prettier": "2.0.5",
 		"typescript": "^4.0.2"
 	},