Add custom push Loki API path support (#39)

* feat: add pushApiPath option for Loki Transport configuration

* test: add unit test for LogPusher with custom pushApiPath

* refactor: rename pushApiPath to endpoint

---------

Co-authored-by: Julien <julien@ripouteau.com>

README.md

@@ -68,6 +68,10 @@ A map of pino log levels to Loki log levels. This can be used to map pino log le
 
 The URL for Loki. This is required.
 
+#### `endpoint`
+
+The path to the Loki push API. Defaults to `/loki/api/v1/push`.
+
 #### `basicAuth`
 
 Basic auth credentials for Loki. An object with the following shape:
@@ -133,6 +137,7 @@ Options:
   -u, --user <user>              Loki username
   -p, --password <password>      Loki password
   --hostname <hostname>          URL for Loki
+  --endpoint <endpoint>          Path to the Loki push API
   -b, --batch                    Should logs be sent in batch mode
   -i, --interval <interval>      The interval at which batched logs are sent in seconds
   -t, --timeout <timeout>        Timeout for request to Loki

src/cli.ts

@@ -10,6 +10,7 @@ program
   .option('-u, --user <user>', 'Loki username')
   .option('-p, --password <password>', 'Loki password')
   .option('--hostname <hostname>', 'URL for Loki')
+  .option('--endpoint <endpoint>', 'Path to the Loki push API')
   .option('-b, --batch', 'Should logs be sent in batch mode')
   .option('-i, --interval <interval>', 'The interval at which batched logs are sent in seconds')
   .option('-t, --timeout <timeout>', 'Timeout for request to Loki')
@@ -32,6 +33,7 @@ export const createPinoLokiConfigFromArgs = () => {
 
   const config: LokiOptions = {
     host: opts.hostname,
+    endpoint: opts.endpoint,
     timeout: opts.timeout,
     silenceErrors: opts.silenceErrors,
     batching: opts.batch,

src/index.ts

@@ -11,6 +11,7 @@ import type { PinoLog, LokiOptions } from './types'
 function resolveOptions(options: LokiOptions) {
   return {
     ...options,
+    endpoint: options.endpoint ?? 'loki/api/v1/push',
     timeout: options.timeout ?? 30_000,
     silenceErrors: options.silenceErrors ?? false,
     batching: options.batching ?? true,

src/log_pusher.ts

@@ -65,22 +65,25 @@ export class LogPusher {
     debug(`[LogPusher] pushing ${lokiLogs.length} logs to Loki`)
 
     try {
-      const response = await fetch(new URL('loki/api/v1/push', this.#options.host), {
-        method: 'POST',
-        signal: AbortSignal.timeout(this.#options.timeout ?? 30_000),
-        headers: {
-          ...this.#options.headers,
-          ...(this.#options.basicAuth && {
-            Authorization:
-              'Basic ' +
-              Buffer.from(
-                `${this.#options.basicAuth.username}:${this.#options.basicAuth.password}`,
-              ).toString('base64'),
-          }),
-          'Content-Type': 'application/json',
+      const response = await fetch(
+        new URL(this.#options.endpoint ?? 'loki/api/v1/push', this.#options.host),
+        {
+          method: 'POST',
+          signal: AbortSignal.timeout(this.#options.timeout ?? 30_000),
+          headers: {
+            ...this.#options.headers,
+            ...(this.#options.basicAuth && {
+              Authorization:
+                'Basic ' +
+                Buffer.from(
+                  `${this.#options.basicAuth.username}:${this.#options.basicAuth.password}`,
+                ).toString('base64'),
+            }),
+            'Content-Type': 'application/json',
+          },
+          body: JSON.stringify({ streams: lokiLogs }),
         },
-        body: JSON.stringify({ streams: lokiLogs }),
-      })
+      )
 
       if (!response.ok) {
         throw new RequestError('Got error when trying to send log to loki', await response.text())

src/types.ts

@@ -44,6 +44,13 @@ export interface LokiOptions {
    */
   host: string
 
+  /**
+   * Url for Loki push API
+   *
+   * @default loki/api/v1/push
+   */
+  endpoint?: string
+
   /**
    * Timeout for request to Loki
    *

tests/unit/log_pusher.spec.ts

@@ -9,6 +9,9 @@ test.group('LogPusher', (group) => {
     http.post('http://localhost:3100/loki/api/v1/push', () => {
       return new Response(null, { status: 204 })
     }),
+    http.post('http://localhost:3100/loki/api/v1/push/test', () => {
+      return new Response(null, { status: 204 })
+    }),
   )
 
   group.setup(() => {
@@ -87,4 +90,20 @@ test.group('LogPusher', (group) => {
 
     console.error = consoleError
   })
+
+  test("should be send logs to Loki's push API if specified", async ({ assert }) => {
+    const pusher = new LogPusher({
+      host: 'http://localhost:3100',
+      endpoint: 'loki/api/v1/push/test',
+    })
+
+    let url = ''
+    server.events.on('request:start', ({ request }) => {
+      url = request.url
+    })
+
+    pusher.push({ level: 30 })
+
+    assert.equal(url, 'http://localhost:3100/loki/api/v1/push/test')
+  })
 })