From 28b077b84efa378bda7a3c3041d99ee573be9511 Mon Sep 17 00:00:00 2001
From: Joachim Van Herwegen <joachimvh@gmail.com>
Date: Thu, 25 Feb 2021 17:07:30 +0100
Subject: [PATCH] feat: Create initializer to instantiate dynamic pods

---
 src/index.ts                                |  1 +
 src/init/ConfigPodInitializer.ts            | 47 +++++++++++++++++++++
 test/unit/init/ConfigPodInitializer.test.ts | 44 +++++++++++++++++++
 3 files changed, 92 insertions(+)
 create mode 100644 src/init/ConfigPodInitializer.ts
 create mode 100644 test/unit/init/ConfigPodInitializer.test.ts

diff --git a/src/index.ts b/src/index.ts
index d015f9981..1facec8e7 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -18,6 +18,7 @@ export * from './authorization/WebAclAuthorizer';
 // Init
 export * from './init/AclInitializer';
 export * from './init/CliRunner';
+export * from './init/ConfigPodInitializer';
 export * from './init/Initializer';
 export * from './init/LoggerInitializer';
 export * from './init/RootContainerInitializer';
diff --git a/src/init/ConfigPodInitializer.ts b/src/init/ConfigPodInitializer.ts
new file mode 100644
index 000000000..7704a4ddb
--- /dev/null
+++ b/src/init/ConfigPodInitializer.ts
@@ -0,0 +1,47 @@
+import type { ResourceIdentifier } from '../ldp/representation/ResourceIdentifier';
+import { getLoggerFor } from '../logging/LogUtil';
+import type { ComponentsJsFactory } from '../pods/generate/ComponentsJsFactory';
+import { TEMPLATE, TEMPLATE_VARIABLE } from '../pods/generate/variables/Variables';
+import type { KeyValueStorage } from '../storage/keyvalue/KeyValueStorage';
+import type { ResourceStore } from '../storage/ResourceStore';
+import { Initializer } from './Initializer';
+
+/**
+ * Initializes all pods that have been stored and loads them in memory.
+ * This reads the pod settings from a permanent storage and uses those
+ * to create the corresponding ResourceStores in memory,
+ * so this is required every time the server starts.
+ *
+ * Part of the dynamic pod creation.
+ * Reads the contents from the configuration storage, uses those values to instantiate ResourceStores,
+ * and then adds them to the routing storage.
+ * @see {@link ConfigPodManager}, {@link TemplatedPodGenerator}, {@link BaseUrlRouterRule}
+ */
+export class ConfigPodInitializer extends Initializer {
+  protected readonly logger = getLoggerFor(this);
+  private readonly storeFactory: ComponentsJsFactory;
+  private readonly configStorage: KeyValueStorage<string, unknown>;
+  private readonly routingStorage: KeyValueStorage<ResourceIdentifier, ResourceStore>;
+
+  public constructor(storeFactory: ComponentsJsFactory,
+    configStorage: KeyValueStorage<string, unknown>,
+    routingStorage: KeyValueStorage<ResourceIdentifier, ResourceStore>) {
+    super();
+    this.storeFactory = storeFactory;
+    this.configStorage = configStorage;
+    this.routingStorage = routingStorage;
+  }
+
+  public async handle(): Promise<void> {
+    let count = 0;
+    for await (const [ path, value ] of this.configStorage.entries()) {
+      const config = value as NodeJS.Dict<string>;
+      const store: ResourceStore =
+        await this.storeFactory.generate(config[TEMPLATE_VARIABLE.templateConfig]!, TEMPLATE.ResourceStore, config);
+      await this.routingStorage.set({ path }, store);
+      this.logger.debug(`Initialized pod at ${path}`);
+      count += 1;
+    }
+    this.logger.info(`Initialized ${count} dynamic pods.`);
+  }
+}
diff --git a/test/unit/init/ConfigPodInitializer.test.ts b/test/unit/init/ConfigPodInitializer.test.ts
new file mode 100644
index 000000000..c36b5e6cf
--- /dev/null
+++ b/test/unit/init/ConfigPodInitializer.test.ts
@@ -0,0 +1,44 @@
+import { ConfigPodInitializer } from '../../../src/init/ConfigPodInitializer';
+import type { ResourceIdentifier } from '../../../src/ldp/representation/ResourceIdentifier';
+import type { ComponentsJsFactory } from '../../../src/pods/generate/ComponentsJsFactory';
+import { TEMPLATE, TEMPLATE_VARIABLE } from '../../../src/pods/generate/variables/Variables';
+import type { KeyValueStorage } from '../../../src/storage/keyvalue/KeyValueStorage';
+import type { ResourceStore } from '../../../src/storage/ResourceStore';
+
+describe('A ConfigPodInitializer', (): void => {
+  let storeFactory: ComponentsJsFactory;
+  let configStorage: KeyValueStorage<string, unknown>;
+  let routingStorage: KeyValueStorage<ResourceIdentifier, ResourceStore>;
+  let initializer: ConfigPodInitializer;
+  const identifierA = { path: 'http://test.com/A' };
+  const identifierB = { path: 'http://test.com/B' };
+  const configA = { [TEMPLATE_VARIABLE.templateConfig]: 'templateA' };
+  const configB = { [TEMPLATE_VARIABLE.templateConfig]: 'templateB' };
+
+  beforeEach(async(): Promise<void> => {
+    storeFactory = {
+      generate: jest.fn().mockResolvedValue('store'),
+    } as any;
+
+    configStorage = new Map<string, unknown>() as any;
+    await configStorage.set(identifierA.path, configA);
+    await configStorage.set(identifierB.path, configB);
+
+    const map = new Map();
+    routingStorage = {
+      get: async(identifier: ResourceIdentifier): Promise<ResourceStore | undefined> => map.get(identifier.path),
+      set: async(identifier: ResourceIdentifier, value: ResourceStore): Promise<any> => map.set(identifier.path, value),
+    } as any;
+
+    initializer = new ConfigPodInitializer(storeFactory, configStorage, routingStorage);
+  });
+
+  it('generates a pod for every entry in the config storage.', async(): Promise<void> => {
+    await initializer.handle();
+    expect(storeFactory.generate).toHaveBeenCalledTimes(2);
+    expect(storeFactory.generate).toHaveBeenCalledWith('templateA', TEMPLATE.ResourceStore, configA);
+    expect(storeFactory.generate).toHaveBeenCalledWith('templateB', TEMPLATE.ResourceStore, configB);
+    await expect(routingStorage.get(identifierA)).resolves.toBe('store');
+    await expect(routingStorage.get(identifierB)).resolves.toBe('store');
+  });
+});