From 05508a9757d24059928cd800e9b12643c1f98e5f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fredrik=20Adel=C3=B6w?= <freben@gmail.com>
Date: Thu, 14 Sep 2023 14:58:16 +0200
Subject: [PATCH] do not create duplicate db connection pools in the old
 backend
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Signed-off-by: Fredrik Adelöw <freben@gmail.com>
---
 .changeset/angry-ghosts-brush.md              | 13 +++++++++++++
 .changeset/thin-ladybugs-lick.md              |  5 +++++
 .../src/database/DatabaseManager.ts           | 19 ++++++-------------
 packages/backend/src/index.ts                 |  2 +-
 .../default-app/packages/backend/src/index.ts |  2 +-
 5 files changed, 26 insertions(+), 15 deletions(-)
 create mode 100644 .changeset/angry-ghosts-brush.md
 create mode 100644 .changeset/thin-ladybugs-lick.md

diff --git a/.changeset/angry-ghosts-brush.md b/.changeset/angry-ghosts-brush.md
new file mode 100644
index 0000000000..e1f3d7bc04
--- /dev/null
+++ b/.changeset/angry-ghosts-brush.md
@@ -0,0 +1,13 @@
+---
+'@backstage/create-app': patch
+---
+
+Updated the backend template to no longer create duplicate connection pools to plugins that use the task scheduler.
+
+To apply this change in your own repository, perform the following small update:
+
+```diff
+// in packages/backend/src/index.ts
+-  const taskScheduler = TaskScheduler.fromConfig(config);
++  const taskScheduler = TaskScheduler.fromConfig(config, { databaseManager });
+```
diff --git a/.changeset/thin-ladybugs-lick.md b/.changeset/thin-ladybugs-lick.md
new file mode 100644
index 0000000000..41707e22d0
--- /dev/null
+++ b/.changeset/thin-ladybugs-lick.md
@@ -0,0 +1,5 @@
+---
+'@backstage/backend-common': patch
+---
+
+Minor internal refactor
diff --git a/packages/backend-common/src/database/DatabaseManager.ts b/packages/backend-common/src/database/DatabaseManager.ts
index db5d36afad..4b655512bb 100644
--- a/packages/backend-common/src/database/DatabaseManager.ts
+++ b/packages/backend-common/src/database/DatabaseManager.ts
@@ -56,13 +56,14 @@ export type DatabaseManagerOptions = {
 /**
  * Manages database connections for Backstage backend plugins.
  *
+ * @public
+ * @remarks
+ *
  * The database manager allows the user to set connection and client settings on
  * a per pluginId basis by defining a database config block under
  * `plugin.<pluginId>` in addition to top level defaults. Optionally, a user may
  * set `prefix` which is used to prefix generated database names if config is
  * not provided.
- *
- * @public
  */
 export class DatabaseManager {
   /**
@@ -105,17 +106,9 @@ export class DatabaseManager {
       pluginMetadata: PluginMetadataService;
     },
   ): PluginDatabaseManager {
-    const _this = this;
-
-    return {
-      getClient(): Promise<Knex> {
-        return _this.getDatabase(pluginId, deps);
-      },
-      migrations: {
-        skip: false,
-        ..._this.options?.migrations,
-      },
-    };
+    const getClient = () => this.getDatabase(pluginId, deps);
+    const migrations = { skip: false, ...this.options?.migrations };
+    return { getClient, migrations };
   }
 
   /**
diff --git a/packages/backend/src/index.ts b/packages/backend/src/index.ts
index 54f0f98e41..b22f7d2983 100644
--- a/packages/backend/src/index.ts
+++ b/packages/backend/src/index.ts
@@ -93,7 +93,7 @@ function makeCreateEnv(config: Config) {
   });
   const databaseManager = DatabaseManager.fromConfig(config, { logger: root });
   const cacheManager = CacheManager.fromConfig(config);
-  const taskScheduler = TaskScheduler.fromConfig(config);
+  const taskScheduler = TaskScheduler.fromConfig(config, { databaseManager });
   const identity = DefaultIdentityClient.create({
     discovery,
   });
diff --git a/packages/create-app/templates/default-app/packages/backend/src/index.ts b/packages/create-app/templates/default-app/packages/backend/src/index.ts
index 1c08288675..04c4ff9392 100644
--- a/packages/create-app/templates/default-app/packages/backend/src/index.ts
+++ b/packages/create-app/templates/default-app/packages/backend/src/index.ts
@@ -39,7 +39,7 @@ function makeCreateEnv(config: Config) {
   const cacheManager = CacheManager.fromConfig(config);
   const databaseManager = DatabaseManager.fromConfig(config, { logger: root });
   const tokenManager = ServerTokenManager.noop();
-  const taskScheduler = TaskScheduler.fromConfig(config);
+  const taskScheduler = TaskScheduler.fromConfig(config, { databaseManager });
 
   const identity = DefaultIdentityClient.create({
     discovery,