add cache testing utilities

Signed-off-by: Fredrik Adelöw <freben@gmail.com>

.changeset/cyan-jobs-visit.md

@@ -0,0 +1,5 @@
+---
+'@backstage/backend-test-utils': minor
+---
+
+Added `TestCaches` that functions just like `TestDatabases`

.github/workflows/ci.yml

@@ -188,7 +188,7 @@ jobs:
         ports:
           - 3306/tcp
       redis:
-        image: redis
+        image: redis:7
         options: >-
           --health-cmd "redis-cli ping"
           --health-interval 10s
@@ -240,7 +240,7 @@ jobs:
           BACKSTAGE_TEST_DATABASE_POSTGRES16_CONNECTION_STRING: postgresql://postgres:postgres@localhost:${{ job.services.postgres16.ports[5432] }}
           BACKSTAGE_TEST_DATABASE_POSTGRES12_CONNECTION_STRING: postgresql://postgres:postgres@localhost:${{ job.services.postgres12.ports[5432] }}
           BACKSTAGE_TEST_DATABASE_MYSQL8_CONNECTION_STRING: mysql://root:root@localhost:${{ job.services.mysql8.ports[3306] }}/ignored
-          BACKSTAGE_TEST_CACHE_REDIS_CONNECTION_STRING: redis://localhost:${{ job.services.redis.ports[6379] }}
+          BACKSTAGE_TEST_CACHE_REDIS7_CONNECTION_STRING: redis://localhost:${{ job.services.redis.ports[6379] }}
 
       # We run the test cases before verifying the specs to prevent any failing tests from causing errors.
       - name: verify openapi specs against test cases

.github/workflows/deploy_packages.yml

@@ -55,6 +55,15 @@ jobs:
           --health-retries 5
         ports:
           - 3306/tcp
+      redis:
+        image: redis:7
+        options: >-
+          --health-cmd "redis-cli ping"
+          --health-interval 10s
+          --health-timeout 5s
+          --health-retries 5
+        ports:
+          - 6379/tcp
 
     env:
       CI: true
@@ -115,6 +124,7 @@ jobs:
           BACKSTAGE_TEST_DATABASE_POSTGRES16_CONNECTION_STRING: postgresql://postgres:postgres@localhost:${{ job.services.postgres16.ports[5432] }}
           BACKSTAGE_TEST_DATABASE_POSTGRES12_CONNECTION_STRING: postgresql://postgres:postgres@localhost:${{ job.services.postgres12.ports[5432] }}
           BACKSTAGE_TEST_DATABASE_MYSQL8_CONNECTION_STRING: mysql://root:root@localhost:${{ job.services.mysql8.ports[3306] }}/ignored
+          BACKSTAGE_TEST_CACHE_REDIS7_CONNECTION_STRING: redis://localhost:${{ job.services.redis.ports[6379] }}
 
       - name: Discord notification
         if: ${{ failure() }}

packages/backend-defaults/src/entrypoints/cache/CacheManager.test.ts

@@ -14,8 +14,9 @@
  * limitations under the License.
  */
 
-import { mockServices } from '@backstage/backend-test-utils';
+import { mockServices, TestCaches } from '@backstage/backend-test-utils';
 import KeyvRedis from '@keyv/redis';
+import KeyvMemcache from '@keyv/memcache';
 import { CacheManager } from './CacheManager';
 
 // This test is in a separate file because the main test file uses other mocking
@@ -23,28 +24,32 @@ import { CacheManager } from './CacheManager';
 
 // Contrived code because it's hard to spy on a default export
 jest.mock('@keyv/redis', () => {
-  const ActualKeyvRedis = jest.requireActual('@keyv/redis');
+  const Actual = jest.requireActual('@keyv/redis');
   return jest.fn((...args: any[]) => {
-    return new ActualKeyvRedis(...args);
+    return new Actual(...args);
+  });
+});
+jest.mock('@keyv/memcache', () => {
+  const Actual = jest.requireActual('@keyv/memcache');
+  return jest.fn((...args: any[]) => {
+    return new Actual(...args);
   });
 });
 
 describe('CacheManager integration', () => {
-  describe('redis', () => {
-    it('only creates one underlying connection', async () => {
-      const connection =
-        process.env.BACKSTAGE_TEST_CACHE_REDIS7_CONNECTION_STRING;
-      if (!connection) {
-        return;
-      }
+  const caches = TestCaches.create();
+
+  afterEach(jest.clearAllMocks);
+
+  it.each(caches.eachSupportedId())(
+    'only creates one underlying connection, %p',
+    async cacheId => {
+      const { store, connection } = await caches.init(cacheId);
 
       const manager = CacheManager.fromConfig(
         mockServices.rootConfig({
-          data: {
-            backend: { cache: { store: 'redis', connection } },
-          },
+          data: { backend: { cache: { store, connection } } },
         }),
-        { onError: e => expect(e).not.toBeDefined() },
       );
 
       manager.forPlugin('p1').getClient();
@@ -52,25 +57,27 @@ describe('CacheManager integration', () => {
       manager.forPlugin('p2').getClient();
       manager.forPlugin('p3').getClient({});
 
-      expect(KeyvRedis).toHaveBeenCalledTimes(1);
-    });
-
-    it('interacts correctly with redis', async () => {
-      // TODO(freben): This could be frameworkified as TestCaches just like
-      // TestDatabases, but that will have to come some other day
-      const connection =
-        process.env.BACKSTAGE_TEST_CACHE_REDIS7_CONNECTION_STRING;
-      if (!connection) {
-        return;
+      if (store === 'redis') {
+        // eslint-disable-next-line jest/no-conditional-expect
+        expect(KeyvRedis).toHaveBeenCalledTimes(1);
+      } else if (store === 'memcache') {
+        // eslint-disable-next-line jest/no-conditional-expect
+        expect(KeyvMemcache).toHaveBeenCalledTimes(1);
       }
+    },
+  );
+
+  it.each(caches.eachSupportedId())(
+    'interacts correctly with store, %p',
+    async cacheId => {
+      const { store, connection } = await caches.init(cacheId);
 
       const manager = CacheManager.fromConfig(
         mockServices.rootConfig({
           data: {
-            backend: { cache: { store: 'redis', connection } },
+            backend: { cache: { store, connection } },
           },
         }),
-        { onError: e => expect(e).not.toBeDefined() },
       );
 
       const plugin1 = manager.forPlugin('p1').getClient();
@@ -84,6 +91,6 @@ describe('CacheManager integration', () => {
       await expect(plugin1.get('a')).resolves.toBe('plugin1');
       await expect(plugin2a.get('a')).resolves.toBe('plugin2b');
       await expect(plugin2b.get('a')).resolves.toBe('plugin2b');
-    });
-  });
+    },
+  );
 });

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

@@ -25,6 +25,7 @@ import { HttpRouterFactoryOptions } from '@backstage/backend-app-api';
 import { HttpRouterService } from '@backstage/backend-plugin-api';
 import { IdentityService } from '@backstage/backend-plugin-api';
 import { JsonObject } from '@backstage/types';
+import Keyv from 'keyv';
 import { Knex } from 'knex';
 import { LifecycleService } from '@backstage/backend-plugin-api';
 import { LoggerService } from '@backstage/backend-plugin-api';
@@ -423,6 +424,28 @@ export interface TestBackendOptions<TExtensionPoints extends any[]> {
   >;
 }
 
+// @public
+export type TestCacheId = 'MEMORY' | 'REDIS_7' | 'MEMCACHED_1';
+
+// @public
+export class TestCaches {
+  static create(options?: {
+    ids?: TestCacheId[];
+    disableDocker?: boolean;
+  }): TestCaches;
+  // (undocumented)
+  eachSupportedId(): [TestCacheId][];
+  init(id: TestCacheId): Promise<{
+    store: string;
+    connection: string;
+    keyv: Keyv;
+  }>;
+  // (undocumented)
+  static setDefaults(options: { ids?: TestCacheId[] }): void;
+  // (undocumented)
+  supports(id: TestCacheId): boolean;
+}
+
 // @public
 export type TestDatabaseId =
   | 'POSTGRES_16'

packages/backend-test-utils/package.json

@@ -53,10 +53,14 @@
     "@backstage/plugin-auth-node": "workspace:^",
     "@backstage/plugin-events-node": "workspace:^",
     "@backstage/types": "workspace:^",
+    "@keyv/memcache": "^1.3.5",
+    "@keyv/redis": "^2.5.3",
+    "@types/keyv": "^4.2.0",
     "better-sqlite3": "^9.0.0",
     "cookie": "^0.6.0",
     "express": "^4.17.1",
     "fs-extra": "^11.0.0",
+    "keyv": "^4.5.2",
     "knex": "^3.0.0",
     "msw": "^1.0.0",
     "mysql2": "^3.0.0",

packages/backend-test-utils/src/cache/TestCaches.test.ts

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2024 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.
+ */
+
+import { isDockerDisabledForTests } from '../util';
+import { TestCaches } from './TestCaches';
+
+const itIfDocker = isDockerDisabledForTests() ? it.skip : it;
+
+jest.setTimeout(60_000);
+
+describe('TestCaches', () => {
+  const caches = TestCaches.create();
+
+  it.each(caches.eachSupportedId())('fires up a cache, %p', async cacheId => {
+    const { keyv } = await caches.init(cacheId);
+    await keyv.set('test', 'value');
+    await expect(keyv.get('test')).resolves.toBe('value');
+  });
+
+  itIfDocker('clears between tests, part 1', async () => {
+    const { keyv } = await caches.init('REDIS_7');
+    // eslint-disable-next-line jest/no-standalone-expect
+    await expect(keyv.get('collision')).resolves.toBeUndefined();
+    await keyv.set('collision', 'something');
+  });
+
+  itIfDocker('clears between tests, part 2', async () => {
+    const { keyv } = await caches.init('REDIS_7');
+    // eslint-disable-next-line jest/no-standalone-expect
+    await expect(keyv.get('collision')).resolves.toBeUndefined();
+    await keyv.set('collision', 'something');
+  });
+
+  itIfDocker('clears between tests, part 3', async () => {
+    const { keyv } = await caches.init('REDIS_7');
+    // eslint-disable-next-line jest/no-standalone-expect
+    await expect(keyv.get('collision')).resolves.toBeUndefined();
+    await keyv.set('collision', 'something');
+  });
+});

packages/backend-test-utils/src/cache/TestCaches.ts

@@ -0,0 +1,210 @@
+/*
+ * Copyright 2024 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.
+ */
+
+import Keyv from 'keyv';
+import { isDockerDisabledForTests } from '../util/isDockerDisabledForTests';
+import { connectToExternalMemcache, startMemcachedContainer } from './memcache';
+import { connectToExternalRedis, startRedisContainer } from './redis';
+import { Instance, TestCacheId, TestCacheProperties, allCaches } from './types';
+
+/**
+ * Encapsulates the creation of ephemeral test cache instances for use inside
+ * unit or integration tests.
+ *
+ * @public
+ */
+export class TestCaches {
+  private readonly instanceById: Map<string, Instance>;
+  private readonly supportedIds: TestCacheId[];
+  private static defaultIds?: TestCacheId[];
+
+  /**
+   * Creates an empty `TestCaches` instance, and sets up Jest to clean up all of
+   * its acquired resources after all tests finish.
+   *
+   * You typically want to create just a single instance like this at the top of
+   * your test file or `describe` block, and then call `init` many times on that
+   * instance inside the individual tests. Spinning up a "physical" cache
+   * instance takes a considerable amount of time, slowing down tests. But
+   * wiping the contents of an instance using `init` is very fast.
+   */
+  static create(options?: {
+    ids?: TestCacheId[];
+    disableDocker?: boolean;
+  }): TestCaches {
+    const ids = options?.ids;
+    const disableDocker = options?.disableDocker ?? isDockerDisabledForTests();
+
+    let testCacheIds: TestCacheId[];
+    if (ids) {
+      testCacheIds = ids;
+    } else if (TestCaches.defaultIds) {
+      testCacheIds = TestCaches.defaultIds;
+    } else {
+      testCacheIds = Object.keys(allCaches) as TestCacheId[];
+    }
+
+    const supportedIds = testCacheIds.filter(id => {
+      const properties = allCaches[id];
+      if (!properties) {
+        return false;
+      }
+      // If the caller has set up the env with an explicit connection string,
+      // we'll assume that this target will work
+      if (
+        properties.connectionStringEnvironmentVariableName &&
+        process.env[properties.connectionStringEnvironmentVariableName]
+      ) {
+        return true;
+      }
+      // If the cache doesn't require docker at all, there's nothing to worry
+      // about
+      if (!properties.dockerImageName) {
+        return true;
+      }
+      // If the cache requires docker, but docker is disabled, we will fail.
+      if (disableDocker) {
+        return false;
+      }
+      return true;
+    });
+
+    const caches = new TestCaches(supportedIds);
+
+    if (supportedIds.length > 0) {
+      afterAll(async () => {
+        await caches.shutdown();
+      });
+    }
+
+    return caches;
+  }
+
+  static setDefaults(options: { ids?: TestCacheId[] }) {
+    TestCaches.defaultIds = options.ids;
+  }
+
+  private constructor(supportedIds: TestCacheId[]) {
+    this.instanceById = new Map();
+    this.supportedIds = supportedIds;
+  }
+
+  supports(id: TestCacheId): boolean {
+    return this.supportedIds.includes(id);
+  }
+
+  eachSupportedId(): [TestCacheId][] {
+    return this.supportedIds.map(id => [id]);
+  }
+
+  /**
+   * Returns a fresh, empty cache for the given driver.
+   *
+   * @param id - The ID of the cache to use, e.g. 'REDIS_7'
+   * @returns Cache connection properties
+   */
+  async init(
+    id: TestCacheId,
+  ): Promise<{ store: string; connection: string; keyv: Keyv }> {
+    const properties = allCaches[id];
+    if (!properties) {
+      const candidates = Object.keys(allCaches).join(', ');
+      throw new Error(
+        `Unknown test cache ${id}, possible values are ${candidates}`,
+      );
+    }
+    if (!this.supportedIds.includes(id)) {
+      const candidates = this.supportedIds.join(', ');
+      throw new Error(
+        `Unsupported test cache ${id} for this environment, possible values are ${candidates}`,
+      );
+    }
+
+    // Ensure that a testcontainers instance is up for this ID
+    let instance: Instance | undefined = this.instanceById.get(id);
+    if (!instance) {
+      instance = await this.initAny(properties);
+      this.instanceById.set(id, instance);
+    }
+
+    // Ensure that it's cleared of data from previous tests
+    await instance.keyv.clear();
+
+    return {
+      store: instance.store,
+      connection: instance.connection,
+      keyv: instance.keyv,
+    };
+  }
+
+  private async initAny(properties: TestCacheProperties): Promise<Instance> {
+    switch (properties.store) {
+      case 'memcache':
+        return this.initMemcached(properties);
+      case 'redis':
+        return this.initRedis(properties);
+      case 'memory':
+        return {
+          store: 'memory',
+          connection: 'memory',
+          keyv: new Keyv(),
+          stop: async () => {},
+        };
+      default:
+        throw new Error(`Unknown cache store '${properties.store}'`);
+    }
+  }
+
+  private async initMemcached(
+    properties: TestCacheProperties,
+  ): Promise<Instance> {
+    // Use the connection string if provided
+    const envVarName = properties.connectionStringEnvironmentVariableName;
+    if (envVarName) {
+      const connectionString = process.env[envVarName];
+      if (connectionString) {
+        return connectToExternalMemcache(connectionString);
+      }
+    }
+
+    return await startMemcachedContainer(properties.dockerImageName!);
+  }
+
+  private async initRedis(properties: TestCacheProperties): Promise<Instance> {
+    // Use the connection string if provided
+    const envVarName = properties.connectionStringEnvironmentVariableName;
+    if (envVarName) {
+      const connectionString = process.env[envVarName];
+      if (connectionString) {
+        return connectToExternalRedis(connectionString);
+      }
+    }
+
+    return await startRedisContainer(properties.dockerImageName!);
+  }
+
+  private async shutdown() {
+    const instances = [...this.instanceById.values()];
+    this.instanceById.clear();
+    await Promise.all(
+      instances.map(({ stop }) =>
+        stop().catch(error => {
+          console.warn(`TestCaches: Failed to stop container`, { error });
+        }),
+      ),
+    );
+  }
+}

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

@@ -0,0 +1,18 @@
+/*
+ * 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.
+ */
+
+export { TestCaches } from './TestCaches';
+export type { TestCacheId } from './types';

packages/backend-test-utils/src/cache/memcache.test.ts

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2024 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.
+ */
+
+import { isDockerDisabledForTests } from '../util/isDockerDisabledForTests';
+import { startMemcachedContainer } from './memcache';
+import { v4 as uuid } from 'uuid';
+
+const itIfDocker = isDockerDisabledForTests() ? it.skip : it;
+
+jest.setTimeout(60_000);
+
+describe('startMemcachedContainer', () => {
+  itIfDocker('successfully launches the container', async () => {
+    const { stop, keyv } = await startMemcachedContainer('memcached:1');
+    const value = uuid();
+    await keyv.set('test', value);
+    // eslint-disable-next-line jest/no-standalone-expect
+    await expect(keyv.get('test')).resolves.toBe(value);
+    await stop();
+  });
+});

packages/backend-test-utils/src/cache/memcache.ts

@@ -0,0 +1,83 @@
+/*
+ * Copyright 2024 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.
+ */
+
+import Keyv from 'keyv';
+import KeyvMemcache from '@keyv/memcache';
+import { v4 as uuid } from 'uuid';
+import { Instance } from './types';
+
+async function attemptMemcachedConnection(connection: string): Promise<Keyv> {
+  const startTime = Date.now();
+
+  for (;;) {
+    try {
+      const store = new KeyvMemcache(connection);
+      const keyv = new Keyv({ store });
+      const value = uuid();
+      await keyv.set('test', value);
+      if ((await keyv.get('test')) === value) {
+        return keyv;
+      }
+    } catch (e) {
+      if (Date.now() - startTime > 30_000) {
+        throw new Error(
+          `Timed out waiting for memcached to be ready for connections, ${e}`,
+        );
+      }
+    }
+
+    await new Promise(resolve => setTimeout(resolve, 100));
+  }
+}
+
+export async function connectToExternalMemcache(
+  connection: string,
+): Promise<Instance> {
+  const keyv = await attemptMemcachedConnection(connection);
+  return {
+    store: 'memcache',
+    connection,
+    keyv,
+    stop: async () => await keyv.disconnect(),
+  };
+}
+
+export async function startMemcachedContainer(
+  image: string,
+): Promise<Instance> {
+  // Lazy-load to avoid side-effect of importing testcontainers
+  const { GenericContainer } = await import('testcontainers');
+
+  const container = await new GenericContainer(image)
+    .withExposedPorts(11211)
+    .start();
+
+  const host = container.getHost();
+  const port = container.getMappedPort(11211);
+  const connection = `${host}:${port}`;
+
+  const keyv = await attemptMemcachedConnection(connection);
+
+  return {
+    store: 'memcache',
+    connection,
+    keyv,
+    stop: async () => {
+      await keyv.disconnect();
+      await container.stop({ timeout: 10_000 });
+    },
+  };
+}

packages/backend-test-utils/src/cache/redis.test.ts

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2024 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.
+ */
+
+import { isDockerDisabledForTests } from '../util/isDockerDisabledForTests';
+import { startRedisContainer } from './redis';
+import { v4 as uuid } from 'uuid';
+
+const itIfDocker = isDockerDisabledForTests() ? it.skip : it;
+
+jest.setTimeout(60_000);
+
+describe('startRedisContainer', () => {
+  itIfDocker('successfully launches the container', async () => {
+    const { stop, keyv } = await startRedisContainer('redis:7');
+    const value = uuid();
+    await keyv.set('test', value);
+    // eslint-disable-next-line jest/no-standalone-expect
+    await expect(keyv.get('test')).resolves.toBe(value);
+    await stop();
+  });
+});

packages/backend-test-utils/src/cache/redis.ts

@@ -0,0 +1,81 @@
+/*
+ * Copyright 2024 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.
+ */
+
+import Keyv from 'keyv';
+import KeyvRedis from '@keyv/redis';
+import { v4 as uuid } from 'uuid';
+import { Instance } from './types';
+
+async function attemptRedisConnection(connection: string): Promise<Keyv> {
+  const startTime = Date.now();
+
+  for (;;) {
+    try {
+      const store = new KeyvRedis(connection);
+      const keyv = new Keyv({ store });
+      const value = uuid();
+      await keyv.set('test', value);
+      if ((await keyv.get('test')) === value) {
+        return keyv;
+      }
+    } catch (e) {
+      if (Date.now() - startTime > 30_000) {
+        throw new Error(
+          `Timed out waiting for redis to be ready for connections, ${e}`,
+        );
+      }
+    }
+
+    await new Promise(resolve => setTimeout(resolve, 100));
+  }
+}
+
+export async function connectToExternalRedis(
+  connection: string,
+): Promise<Instance> {
+  const keyv = await attemptRedisConnection(connection);
+  return {
+    store: 'redis',
+    connection,
+    keyv,
+    stop: async () => await keyv.disconnect(),
+  };
+}
+
+export async function startRedisContainer(image: string): Promise<Instance> {
+  // Lazy-load to avoid side-effect of importing testcontainers
+  const { GenericContainer } = await import('testcontainers');
+
+  const container = await new GenericContainer(image)
+    .withExposedPorts(6379)
+    .start();
+
+  const host = container.getHost();
+  const port = container.getMappedPort(6379);
+  const connection = `redis://${host}:${port}`;
+
+  const keyv = await attemptRedisConnection(connection);
+
+  return {
+    store: 'redis',
+    connection,
+    keyv,
+    stop: async () => {
+      await keyv.disconnect();
+      await container.stop({ timeout: 10_000 });
+    },
+  };
+}

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

@@ -0,0 +1,61 @@
+/*
+ * Copyright 2024 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.
+ */
+
+import Keyv from 'keyv';
+import { getDockerImageForName } from '../util/getDockerImageForName';
+
+/**
+ * The possible caches to test against.
+ *
+ * @public
+ */
+export type TestCacheId = 'MEMORY' | 'REDIS_7' | 'MEMCACHED_1';
+
+export type TestCacheProperties = {
+  name: string;
+  store: string;
+  dockerImageName?: string;
+  connectionStringEnvironmentVariableName?: string;
+};
+
+export type Instance = {
+  store: string;
+  connection: string;
+  keyv: Keyv;
+  stop: () => Promise<void>;
+};
+
+export const allCaches: Record<TestCacheId, TestCacheProperties> =
+  Object.freeze({
+    REDIS_7: {
+      name: 'Redis 7.x',
+      store: 'redis',
+      dockerImageName: getDockerImageForName('redis:7'),
+      connectionStringEnvironmentVariableName:
+        'BACKSTAGE_TEST_CACHE_REDIS7_CONNECTION_STRING',
+    },
+    MEMCACHED_1: {
+      name: 'Memcached 1.x',
+      store: 'memcache',
+      dockerImageName: getDockerImageForName('memcached:1'),
+      connectionStringEnvironmentVariableName:
+        'BACKSTAGE_TEST_CACHE_MEMCACHED1_CONNECTION_STRING',
+    },
+    MEMORY: {
+      name: 'In-memory',
+      store: 'memory',
+    },
+  });

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

@@ -14,6 +14,5 @@
  * limitations under the License.
  */
 
-export { isDockerDisabledForTests } from '../util/isDockerDisabledForTests';
 export { TestDatabases } from './TestDatabases';
 export type { TestDatabaseId } from './types';

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

@@ -20,6 +20,7 @@
  * @packageDocumentation
  */
 
+export * from './cache';
 export * from './database';
 export * from './msw';
 export * from './filesystem';

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

@@ -20,7 +20,7 @@ export function isDockerDisabledForTests() {
   // the (relatively heavy, long running) docker based tests. If you want to
   // still run local tests for all databases, just pass either the CI=1 env
   // parameter to your test runner, or individual connection strings per
-  // database.
+  // database or cache.
   return (
     Boolean(process.env.BACKSTAGE_TEST_DISABLE_DOCKER) ||
     !Boolean(process.env.CI)

yarn.lock

@@ -3582,11 +3582,15 @@ __metadata:
     "@backstage/plugin-auth-node": "workspace:^"
     "@backstage/plugin-events-node": "workspace:^"
     "@backstage/types": "workspace:^"
+    "@keyv/memcache": ^1.3.5
+    "@keyv/redis": ^2.5.3
+    "@types/keyv": ^4.2.0
     "@types/supertest": ^2.0.8
     better-sqlite3: ^9.0.0
     cookie: ^0.6.0
     express: ^4.17.1
     fs-extra: ^11.0.0
+    keyv: ^4.5.2
     knex: ^3.0.0
     msw: ^1.0.0
     mysql2: ^3.0.0
@@ -17510,7 +17514,16 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@types/keyv@npm:*, @types/keyv@npm:^3.1.1":
+"@types/keyv@npm:*, @types/keyv@npm:^4.2.0":
+  version: 4.2.0
+  resolution: "@types/keyv@npm:4.2.0"
+  dependencies:
+    keyv: "*"
+  checksum: 8713da9382b9346d664866a6cab2f91b0fd479f61379af891303a618e9a2abad6f347adc38a0850540e3f2dad278427de24e7555339264fddb04d1d17d3b50e0
+  languageName: node
+  linkType: hard
+
+"@types/keyv@npm:^3.1.1":
   version: 3.1.4
   resolution: "@types/keyv@npm:3.1.4"
   dependencies:
@@ -31023,6 +31036,15 @@ __metadata:
   languageName: node
   linkType: hard
 
+"keyv@npm:*, keyv@npm:^4.0.0, keyv@npm:^4.5.2":
+  version: 4.5.4
+  resolution: "keyv@npm:4.5.4"
+  dependencies:
+    json-buffer: 3.0.1
+  checksum: 74a24395b1c34bd44ad5cb2b49140d087553e170625240b86755a6604cd65aa16efdbdeae5cdb17ba1284a0fbb25ad06263755dbc71b8d8b06f74232ce3cdd72
+  languageName: node
+  linkType: hard
+
 "keyv@npm:^3.0.0":
   version: 3.1.0
   resolution: "keyv@npm:3.1.0"
@@ -31032,15 +31054,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"keyv@npm:^4.0.0, keyv@npm:^4.5.2":
-  version: 4.5.4
-  resolution: "keyv@npm:4.5.4"
-  dependencies:
-    json-buffer: 3.0.1
-  checksum: 74a24395b1c34bd44ad5cb2b49140d087553e170625240b86755a6604cd65aa16efdbdeae5cdb17ba1284a0fbb25ad06263755dbc71b8d8b06f74232ce3cdd72
-  languageName: node
-  linkType: hard
-
 "kind-of@npm:^6.0.2, kind-of@npm:^6.0.3":
   version: 6.0.3
   resolution: "kind-of@npm:6.0.3"