From 2ffd316444e08b16517e8172e76e93c0a52c63de Mon Sep 17 00:00:00 2001
From: Geof Holbrook <geof.holbrook@radancy.com>
Date: Thu, 26 Oct 2023 11:45:28 -0400
Subject: [PATCH] pushgateway: adds configuration for omitting job name (for
 gravel gateway compatibility, etc.)

---
 CHANGELOG.md            |  2 ++
 README.md               | 10 ++++++++++
 lib/pushgateway.js      | 26 ++++++++++++++++----------
 test/pushgatewayTest.js | 17 +++++++++++++++++
 4 files changed, 45 insertions(+), 10 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 127771a1..829147aa 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,6 +16,8 @@ project adheres to [Semantic Versioning](http://semver.org/).
 
 ### Added
 
+- Allow Pushgateway to now require job names for compatibility with Gravel Gateway.
+
 ## [15.0.0] - 2023-10-09
 
 ### Breaking
diff --git a/README.md b/README.md
index 9125dd37..a0d0684d 100644
--- a/README.md
+++ b/README.md
@@ -581,6 +581,16 @@ gateway = new client.Pushgateway('http://127.0.0.1:9091', {
 });
 ```
 
+Some gateways such as [Gravel Gateway](https://github.com/sinkingpoint/prometheus-gravel-gateway) do not support grouping by job name, exposing a plain `/metrics` endpoint instead of `/metrics/job/<jobName>`. It's possible to configure a gateway instance to not require a jobName in the options argument.
+
+```js
+gravelGateway = new client.Pushgateway('http://127.0.0.1:9091', {
+  timeout: 5000,
+  requireJobName: false,
+});
+gravelGateway.pushAdd();
+```
+
 ### Bucket Generators
 
 For convenience, there are two bucket generator functions - linear and
diff --git a/lib/pushgateway.js b/lib/pushgateway.js
index d2bc64d5..8ea65569 100644
--- a/lib/pushgateway.js
+++ b/lib/pushgateway.js
@@ -13,27 +13,32 @@ class Pushgateway {
 		}
 		this.registry = registry;
 		this.gatewayUrl = gatewayUrl;
-		this.requestOptions = Object.assign({}, options);
+		const { requireJobName, ...requestOptions } = {
+			requireJobName: true,
+			...options,
+		};
+		this.requireJobName = requireJobName;
+		this.requestOptions = requestOptions;
 	}
 
-	pushAdd(params) {
-		if (!params || !params.jobName) {
+	pushAdd(params = {}) {
+		if (this.requireJobName && !params.jobName) {
 			throw new Error('Missing jobName parameter');
 		}
 
 		return useGateway.call(this, 'POST', params.jobName, params.groupings);
 	}
 
-	push(params) {
-		if (!params || !params.jobName) {
+	push(params = {}) {
+		if (this.requireJobName && !params.jobName) {
 			throw new Error('Missing jobName parameter');
 		}
 
 		return useGateway.call(this, 'PUT', params.jobName, params.groupings);
 	}
 
-	delete(params) {
-		if (!params || !params.jobName) {
+	delete(params = {}) {
+		if (this.requireJobName && !params.jobName) {
 			throw new Error('Missing jobName parameter');
 		}
 
@@ -48,9 +53,10 @@ async function useGateway(method, job, groupings) {
 		gatewayUrlParsed.pathname && gatewayUrlParsed.pathname !== '/'
 			? gatewayUrlParsed.pathname
 			: '';
-	const path = `${gatewayUrlPath}/metrics/job/${encodeURIComponent(
-		job,
-	)}${generateGroupings(groupings)}`;
+	const jobPath = job
+		? `/job/${encodeURIComponent(job)}${generateGroupings(groupings)}`
+		: '';
+	const path = `${gatewayUrlPath}/metrics${jobPath}`;
 
 	// eslint-disable-next-line node/no-deprecated-api
 	const target = url.resolve(this.gatewayUrl, path);
diff --git a/test/pushgatewayTest.js b/test/pushgatewayTest.js
index 03ab68a3..f7a510e9 100644
--- a/test/pushgatewayTest.js
+++ b/test/pushgatewayTest.js
@@ -96,6 +96,23 @@ describe.each([
 						expect(err.message).toStrictEqual('Pushgateway request timed out');
 					});
 			});
+
+			it('should be possible to configure for gravel gateway integration (no job name required in path)', async () => {
+				const mockHttp = nock('http://192.168.99.100:9091')
+					.post('/metrics', body)
+					.reply(200);
+
+				instance = new Pushgateway(
+					'http://192.168.99.100:9091',
+					{
+						timeout: 10,
+						requireJobName: false,
+					},
+					registry,
+				);
+
+				return instance.pushAdd().then(() => expect(mockHttp.isDone()));
+			});
 		});
 
 		describe('push', () => {