feat: allow specifying custom Docker registry for tests

this allows to utilize private Docker registries for the tests that are
pulling images for the database tests.

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

.changeset/angry-ducks-shake.md

@@ -0,0 +1,5 @@
+---
+'@backstage/backend-test-utils': patch
+---
+
+Allow specifying custom Docker registry for database tests

packages/backend-test-utils/README.md

@@ -12,6 +12,26 @@ cd plugins/my-plugin-backend
 yarn add --dev @backstage/backend-test-utils
 ```
 
+## Environment variables
+
+- `BACKSTAGE_TEST_DISABLE_DOCKER`
+  - Setting the value to `1` disables Docker for tests
+- `CI`
+  - Setting the value to `1` enables long-running tests, including the ones utilizing Docker
+- `BACKSTAGE_TEST_DOCKER_REGISTRY`
+  - Docker registry mirror address where to pull images for tests, for example `mycompany.docker.io/mirror`
+  - See [documentation](https://node.testcontainers.org/configuration/) for information
+    about authentication (`DOCKER_AUTH_CONFIG`)
+
+Connection strings for different databases that are used for testing. The value of the
+string should point to the running instance of the database.
+
+- `BACKSTAGE_TEST_DATABASE_POSTGRES13_CONNECTION_STRING`
+- `BACKSTAGE_TEST_DATABASE_POSTGRES12_CONNECTION_STRING`
+- `BACKSTAGE_TEST_DATABASE_POSTGRES11_CONNECTION_STRING`
+- `BACKSTAGE_TEST_DATABASE_POSTGRES9_CONNECTION_STRING`
+- `BACKSTAGE_TEST_DATABASE_MYSQL8_CONNECTION_STRING`
+
 ## Documentation
 
 - [Backstage Readme](https://github.com/backstage/backstage/blob/master/README.md)

packages/backend-test-utils/api-report.md

@@ -25,6 +25,9 @@ import { ServiceRef } from '@backstage/backend-plugin-api';
 import { TokenManagerService } from '@backstage/backend-plugin-api';
 import { UrlReaderService } from '@backstage/backend-plugin-api';
 
+// @public (undocumented)
+export const getDockerImageForName: (name: string) => string;
+
 // @public (undocumented)
 export function isDockerDisabledForTests(): boolean;
 

packages/backend-test-utils/src/database/types.ts

@@ -16,6 +16,7 @@
 
 import { DatabaseManager } from '@backstage/backend-common';
 import { Knex } from 'knex';
+import { getDockerImageForName } from '../util';
 
 /**
  * The possible databases to test against.
@@ -48,35 +49,35 @@ export const allDatabases: Record<TestDatabaseId, TestDatabaseProperties> =
     POSTGRES_13: {
       name: 'Postgres 13.x',
       driver: 'pg',
-      dockerImageName: 'postgres:13',
+      dockerImageName: getDockerImageForName('postgres:13'),
       connectionStringEnvironmentVariableName:
         'BACKSTAGE_TEST_DATABASE_POSTGRES13_CONNECTION_STRING',
     },
     POSTGRES_12: {
       name: 'Postgres 12.x',
       driver: 'pg',
-      dockerImageName: 'postgres:12',
+      dockerImageName: getDockerImageForName('postgres:12'),
       connectionStringEnvironmentVariableName:
         'BACKSTAGE_TEST_DATABASE_POSTGRES12_CONNECTION_STRING',
     },
     POSTGRES_11: {
       name: 'Postgres 11.x',
       driver: 'pg',
-      dockerImageName: 'postgres:11',
+      dockerImageName: getDockerImageForName('postgres:11'),
       connectionStringEnvironmentVariableName:
         'BACKSTAGE_TEST_DATABASE_POSTGRES11_CONNECTION_STRING',
     },
     POSTGRES_9: {
       name: 'Postgres 9.x',
       driver: 'pg',
-      dockerImageName: 'postgres:9',
+      dockerImageName: getDockerImageForName('postgres:9'),
       connectionStringEnvironmentVariableName:
         'BACKSTAGE_TEST_DATABASE_POSTGRES9_CONNECTION_STRING',
     },
     MYSQL_8: {
       name: 'MySQL 8.x',
       driver: 'mysql2',
-      dockerImageName: 'mysql:8',
+      dockerImageName: getDockerImageForName('mysql:8'),
       connectionStringEnvironmentVariableName:
         'BACKSTAGE_TEST_DATABASE_MYSQL8_CONNECTION_STRING',
     },

packages/backend-test-utils/src/util/getDockerImageForName.ts

@@ -0,0 +1,22 @@
+/*
+ * Copyright 2021 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/** @public */
+export const getDockerImageForName = (name: string) => {
+  return process.env.BACKSTAGE_TEST_DOCKER_REGISTRY
+    ? `${process.env.BACKSTAGE_TEST_DOCKER_REGISTRY}/${name}`
+    : name;
+};

packages/backend-test-utils/src/util/index.ts

@@ -15,3 +15,4 @@
  */
 
 export { isDockerDisabledForTests } from './isDockerDisabledForTests';
+export { getDockerImageForName } from './getDockerImageForName';