From 8786b93ef22f96255fcf5215f19d266f6298c63a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fredrik=20Adel=C3=B6w?= <freben@gmail.com>
Date: Tue, 30 Apr 2024 09:31:44 +0200
Subject: [PATCH] add back ddl limiter
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Signed-off-by: Fredrik Adelöw <freben@gmail.com>
---
 .../backend-common/src/database/connectors/mysql.ts  |  8 ++++++--
 .../src/database/connectors/postgres.ts              | 12 +++++++++---
 2 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/packages/backend-common/src/database/connectors/mysql.ts b/packages/backend-common/src/database/connectors/mysql.ts
index 25594d5021..1ad8b0b3be 100644
--- a/packages/backend-common/src/database/connectors/mysql.ts
+++ b/packages/backend-common/src/database/connectors/mysql.ts
@@ -23,11 +23,15 @@ import { InputError } from '@backstage/errors';
 import { JsonObject } from '@backstage/types';
 import knexFactory, { Knex } from 'knex';
 import { merge, omit } from 'lodash';
+import limiterFactory from 'p-limit';
 import yn from 'yn';
 import { Connector, DatabaseConnector } from '../types';
 import defaultNameOverride from './defaultNameOverride';
 import { mergeDatabaseConfig } from './mergeDatabaseConfig';
 
+// Limits the number of concurrent DDL operations to 1
+const ddlLimiter = limiterFactory(1);
+
 /**
  * Creates a knex mysql database connection
  *
@@ -174,7 +178,7 @@ export async function ensureMysqlDatabaseExists(
         let lastErr: Error | undefined = undefined;
         for (let i = 0; i < 3; i++) {
           try {
-            return await ensureDatabase(database);
+            return await ddlLimiter(() => ensureDatabase(database));
           } catch (err) {
             lastErr = err;
           }
@@ -214,7 +218,7 @@ export async function dropMysqlDatabase(
     };
     await Promise.all(
       databases.map(async database => {
-        return await dropDatabase(database);
+        return await ddlLimiter(() => dropDatabase(database));
       }),
     );
   } finally {
diff --git a/packages/backend-common/src/database/connectors/postgres.ts b/packages/backend-common/src/database/connectors/postgres.ts
index 39a1073a30..1ddc096e05 100644
--- a/packages/backend-common/src/database/connectors/postgres.ts
+++ b/packages/backend-common/src/database/connectors/postgres.ts
@@ -23,12 +23,16 @@ import { ForwardedError, InputError } from '@backstage/errors';
 import { JsonObject } from '@backstage/types';
 import knexFactory, { Knex } from 'knex';
 import { merge, omit } from 'lodash';
+import limiterFactory from 'p-limit';
 import { Client } from 'pg';
 import { Connector, DatabaseConnector } from '../types';
 import defaultNameOverride from './defaultNameOverride';
 import defaultSchemaOverride from './defaultSchemaOverride';
 import { mergeDatabaseConfig } from './mergeDatabaseConfig';
 
+// Limits the number of concurrent DDL operations to 1
+const ddlLimiter = limiterFactory(1);
+
 /**
  * Creates a knex postgres database connection
  *
@@ -159,7 +163,7 @@ export async function ensurePgDatabaseExists(
         let lastErr: Error | undefined = undefined;
         for (let i = 0; i < 3; i++) {
           try {
-            return await ensureDatabase(database);
+            return await ddlLimiter(() => ensureDatabase(database));
           } catch (err) {
             lastErr = err;
           }
@@ -198,7 +202,9 @@ export async function ensurePgSchemaExists(
       }
     };
 
-    await Promise.all(schemas.map(ensureSchema));
+    await Promise.all(
+      schemas.map(database => ddlLimiter(() => ensureSchema(database))),
+    );
   } finally {
     await admin.destroy();
   }
@@ -218,7 +224,7 @@ export async function dropPgDatabase(
   try {
     await Promise.all(
       databases.map(async database => {
-        await admin.raw(`DROP DATABASE ??`, [database]);
+        await ddlLimiter(() => admin.raw(`DROP DATABASE ??`, [database]));
       }),
     );
   } finally {