feat: allow defining custom build log transport for techdocs

should enable way to overcome #24583 memory leak, maybe.

Signed-off-by: Heikki Hellgren <heikki.hellgren@op.fi>

plugins/techdocs-backend/src/plugin.ts

@@ -38,6 +38,7 @@ import {
 } from '@backstage/plugin-techdocs-node';
 import Docker from 'dockerode';
 import { createRouter } from '@backstage/plugin-techdocs-backend';
+import * as winston from 'winston';
 
 /**
  * The TechDocs plugin is responsible for serving and building documentation for any entity.
@@ -47,6 +48,7 @@ export const techdocsPlugin = createBackendPlugin({
   pluginId: 'techdocs',
   register(env) {
     let docsBuildStrategy: DocsBuildStrategy | undefined;
+    let buildLogTransport: winston.transport | undefined;
     env.registerExtensionPoint(techdocsBuildsExtensionPoint, {
       setBuildStrategy(buildStrategy: DocsBuildStrategy) {
         if (docsBuildStrategy) {
@@ -54,6 +56,12 @@ export const techdocsPlugin = createBackendPlugin({
         }
         docsBuildStrategy = buildStrategy;
       },
+      setBuildLogTransport(transport: winston.transport) {
+        if (buildLogTransport) {
+          throw new Error('BuildLogTransport may only be set once');
+        }
+        buildLogTransport = transport;
+      },
     });
 
     let customTechdocsGenerator: TechdocsGenerator | undefined;
@@ -138,6 +146,7 @@ export const techdocsPlugin = createBackendPlugin({
             logger: winstonLogger,
             cache: cacheManager,
             docsBuildStrategy,
+            buildLogTransport,
             preparers,
             generators,
             publisher,