From 2e20518cd2d16940fff1f8069e43593e0702e86a Mon Sep 17 00:00:00 2001
From: Patrik Oldsberg <poldsberg@gmail.com>
Date: Fri, 3 May 2024 11:43:07 +0200
Subject: [PATCH] catalog-node: allow location analyzer to be configured as a
 factory as well

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>
---
 .../src/service/CatalogPlugin.ts              | 26 +++++++++++++++----
 plugins/catalog-node/api-report-alpha.md      |  8 +++++-
 plugins/catalog-node/src/extensions.ts        | 17 +++++++++---
 3 files changed, 42 insertions(+), 9 deletions(-)

diff --git a/plugins/catalog-backend/src/service/CatalogPlugin.ts b/plugins/catalog-backend/src/service/CatalogPlugin.ts
index 6171ebbc1c..ac869cdc2b 100644
--- a/plugins/catalog-backend/src/service/CatalogPlugin.ts
+++ b/plugins/catalog-backend/src/service/CatalogPlugin.ts
@@ -38,6 +38,7 @@ import {
 } from '@backstage/plugin-catalog-node';
 import { merge } from 'lodash';
 import { Permission } from '@backstage/plugin-permission-common';
+import { ForwardedError } from '@backstage/errors';
 
 class CatalogProcessingExtensionPointImpl
   implements CatalogProcessingExtensionPoint
@@ -164,14 +165,24 @@ export const catalogPlugin = createBackendPlugin({
       processingExtensions,
     );
 
-    let locationAnalyzer: LocationAnalyzer | undefined = undefined;
+    let locationAnalyzerFactory:
+      | ((options: {
+          scmLocationAnalyzers: ScmLocationAnalyzer[];
+        }) => Promise<{ locationAnalyzer: LocationAnalyzer }>)
+      | undefined = undefined;
     const scmLocationAnalyzers = new Array<ScmLocationAnalyzer>();
     env.registerExtensionPoint(catalogAnalysisExtensionPoint, {
-      setLocationAnalyzer(analyzer: LocationAnalyzer) {
-        if (locationAnalyzer) {
+      setLocationAnalyzer(analyzerOrFactory) {
+        if (locationAnalyzerFactory) {
           throw new Error('LocationAnalyzer has already been set');
         }
-        locationAnalyzer = analyzer;
+        if (typeof analyzerOrFactory === 'function') {
+          locationAnalyzerFactory = analyzerOrFactory;
+        } else {
+          locationAnalyzerFactory = async () => ({
+            locationAnalyzer: analyzerOrFactory,
+          });
+        }
       },
       addScmLocationAnalyzer(analyzer: ScmLocationAnalyzer) {
         scmLocationAnalyzers.push(analyzer);
@@ -240,7 +251,12 @@ export const catalogPlugin = createBackendPlugin({
         Object.entries(processingExtensions.placeholderResolvers).forEach(
           ([key, resolver]) => builder.setPlaceholderResolver(key, resolver),
         );
-        if (locationAnalyzer) {
+        if (locationAnalyzerFactory) {
+          const { locationAnalyzer } = await locationAnalyzerFactory({
+            scmLocationAnalyzers,
+          }).catch(e => {
+            throw new ForwardedError('Failed to create LocationAnalyzer', e);
+          });
           builder.setLocationAnalyzer(locationAnalyzer);
         } else {
           builder.addLocationAnalyzers(...scmLocationAnalyzers);
diff --git a/plugins/catalog-node/api-report-alpha.md b/plugins/catalog-node/api-report-alpha.md
index cc3f7e5fb5..b61d1b1d27 100644
--- a/plugins/catalog-node/api-report-alpha.md
+++ b/plugins/catalog-node/api-report-alpha.md
@@ -22,7 +22,13 @@ import { Validators } from '@backstage/catalog-model';
 // @alpha (undocumented)
 export interface CatalogAnalysisExtensionPoint {
   addScmLocationAnalyzer(analyzer: ScmLocationAnalyzer): void;
-  setLocationAnalyzer(analyzer: LocationAnalyzer): void;
+  setLocationAnalyzer(
+    analyzerOrFactory:
+      | LocationAnalyzer
+      | ((options: { scmLocationAnalyzers: ScmLocationAnalyzer[] }) => Promise<{
+          locationAnalyzer: LocationAnalyzer;
+        }>),
+  ): void;
 }
 
 // @alpha (undocumented)
diff --git a/plugins/catalog-node/src/extensions.ts b/plugins/catalog-node/src/extensions.ts
index 56478ec1db..7c1fe6c30d 100644
--- a/plugins/catalog-node/src/extensions.ts
+++ b/plugins/catalog-node/src/extensions.ts
@@ -81,10 +81,21 @@ export const catalogProcessingExtensionPoint =
  */
 export interface CatalogAnalysisExtensionPoint {
   /**
-   * Replaces the entire location analyzer with a new one. This will cause any
-   * SCM analyzers added through `addScmLocationAnalyzer` to be ignored.
+   * Replaces the entire location analyzer with a new one.
+   *
+   * @remarks
+   *
+   * By providing a factory function you can access all the SCM analyzers that
+   * have been added through `addScmLocationAnalyzer`. If you provide a
+   * `LocationAnalyzer` directly, the SCM analyzers will be ignored.
    */
-  setLocationAnalyzer(analyzer: LocationAnalyzer): void;
+  setLocationAnalyzer(
+    analyzerOrFactory:
+      | LocationAnalyzer
+      | ((options: {
+          scmLocationAnalyzers: ScmLocationAnalyzer[];
+        }) => Promise<{ locationAnalyzer: LocationAnalyzer }>),
+  ): void;
 
   /**
    * Adds an analyzer for a specific SCM type to the default location analyzer.