chore: adds LDTransactionalFeatureStore, LDTransactionalDataSourceUpdates, and FDv2 DataSource impls. (#833)

**Requirements**

- [x] I have added test coverage for new or changed functionality
- [x] I have followed the repository's [pull request submission
guidelines](../blob/main/CONTRIBUTING.md#submitting-pull-requests)
- [x] I have validated my changes against all supported platform
versions

This PR moves changes for FDv2 from the temporary holding branch to
main. All picked code has been previously reviewed and was picked from
the temporary holding branch using file pick commands.

Resolved conflicts with @abarker-launchdarkly's recent initMetadata
changes. Please verify those conflict resolutions @abarker-launchdarkly
.

---------

Co-authored-by: Todd Anderson <[email protected]>

Author: tanderson-ld

packages/shared/common/src/api/subsystem/DataSystem/DataSource.ts

@@ -23,7 +23,7 @@ export interface DataSource {
   ): void;
 
   /**
-   * May be called any number of times, if already stopped, has no effect.
+   * May be called any number of times, if already stopped, has no effect. Datasource will not make any additional callbacks after stop returns.
    */
   stop(): void;
 }

packages/shared/sdk-server/__tests__/data_sources/DataSourceUpdates.test.ts

@@ -2,9 +2,9 @@ import { AsyncQueue } from 'launchdarkly-js-test-helpers';
 
 import { internal } from '@launchdarkly/js-sdk-common';
 
-import { LDFeatureStore } from '../../src/api/subsystems';
+import { LDTransactionalFeatureStore } from '../../src/api/subsystems';
 import promisify from '../../src/async/promisify';
-import DataSourceUpdates from '../../src/data_sources/DataSourceUpdates';
+import DataSourceUpdates from '../../src/data_sources/TransactionalDataSourceUpdates';
 import InMemoryFeatureStore from '../../src/store/InMemoryFeatureStore';
 import VersionedDataKinds from '../../src/store/VersionedDataKinds';
 
@@ -13,21 +13,28 @@ type InitMetadata = internal.InitMetadata;
 it('passes initialization metadata to underlying feature store', () => {
   const metadata: InitMetadata = { environmentId: '12345' };
   const store = new InMemoryFeatureStore();
-  store.init = jest.fn();
+  store.applyChanges = jest.fn();
   const updates = new DataSourceUpdates(
     store,
     () => false,
     () => {},
   );
   updates.init({}, () => {}, metadata);
-  expect(store.init).toHaveBeenCalledTimes(1);
-  expect(store.init).toHaveBeenNthCalledWith(1, expect.any(Object), expect.any(Function), metadata);
+  expect(store.applyChanges).toHaveBeenCalledTimes(1);
+  expect(store.applyChanges).toHaveBeenNthCalledWith(
+    1,
+    true,
+    expect.any(Object),
+    expect.any(Function),
+    metadata,
+    undefined,
+  );
 });
 
 describe.each([true, false])(
   'given a DataSourceUpdates with in memory store and change listeners: %s',
   (listen) => {
-    let store: LDFeatureStore;
+    let store: LDTransactionalFeatureStore;
     let updates: DataSourceUpdates;
 
     const queue = new AsyncQueue<string>();

packages/shared/sdk-server/__tests__/data_sources/OneShotInitializerFDv2.test.ts

@@ -0,0 +1,77 @@
+import { subsystem } from '../../src';
+import OneShotInitializerFDv2 from '../../src/data_sources/OneShotInitializerFDv2';
+import Requestor from '../../src/data_sources/Requestor';
+import TestLogger from '../Logger';
+
+describe('given a one shot initializer', () => {
+  const requestor = {
+    requestAllData: jest.fn(),
+  };
+  const allEvents = {
+    events: [
+      {
+        event: 'server-intent',
+        data: { payloads: [{ code: 'xfer-full', id: 'mockId' }] },
+      },
+      {
+        event: 'put-object',
+        data: {
+          kind: 'flag',
+          key: 'flagA',
+          version: 123,
+          object: { objectFieldA: 'objectValueA' },
+        },
+      },
+      {
+        event: 'payload-transferred',
+        data: { state: 'mockState', version: 1 },
+      },
+    ],
+  };
+  const jsonData = JSON.stringify(allEvents);
+
+  let initializer: OneShotInitializerFDv2;
+  const mockDataCallback = jest.fn();
+  const mockStatusCallback = jest.fn();
+  let testLogger: TestLogger;
+
+  beforeEach(() => {
+    testLogger = new TestLogger();
+    initializer = new OneShotInitializerFDv2(requestor as unknown as Requestor, testLogger);
+  });
+
+  afterEach(() => {
+    initializer.stop();
+    jest.restoreAllMocks();
+  });
+
+  it('makes no requests before being started', () => {
+    expect(requestor.requestAllData).not.toHaveBeenCalled();
+  });
+
+  it('polls immediately on start', () => {
+    initializer.start(mockDataCallback, mockStatusCallback);
+    expect(requestor.requestAllData).toHaveBeenCalledTimes(1);
+    expect(mockDataCallback).not.toHaveBeenCalled();
+    expect(mockStatusCallback).toHaveBeenNthCalledWith(1, subsystem.DataSourceState.Initializing);
+  });
+
+  it('calls callback on success', () => {
+    requestor.requestAllData = jest.fn((cb) => cb(undefined, jsonData));
+    initializer.start(mockDataCallback, mockStatusCallback);
+    expect(mockDataCallback).toHaveBeenNthCalledWith(1, true, {
+      basis: true,
+      id: `mockId`,
+      state: `mockState`,
+      updates: [
+        {
+          kind: `flag`,
+          key: `flagA`,
+          version: 123,
+          object: { objectFieldA: 'objectValueA' },
+        },
+      ],
+      version: 1,
+    });
+  });
+});

packages/shared/sdk-server/__tests__/data_sources/PollingProcessor.test.ts

@@ -1,16 +1,12 @@
-import { ClientContext } from '@launchdarkly/js-sdk-common';
-
 import { LDFeatureStore } from '../../src';
 import PollingProcessor from '../../src/data_sources/PollingProcessor';
 import Requestor from '../../src/data_sources/Requestor';
-import Configuration from '../../src/options/Configuration';
 import AsyncStoreFacade from '../../src/store/AsyncStoreFacade';
 import InMemoryFeatureStore from '../../src/store/InMemoryFeatureStore';
 import VersionedDataKinds from '../../src/store/VersionedDataKinds';
-import { createBasicPlatform } from '../createBasicPlatform';
 import TestLogger, { LogLevel } from '../Logger';
 
-describe('given an event processor', () => {
+describe('given a polling processor', () => {
   const requestor = {
     requestAllData: jest.fn(),
   };
@@ -23,24 +19,19 @@ describe('given an event processor', () => {
 
   let store: LDFeatureStore;
   let storeFacade: AsyncStoreFacade;
-  let config: Configuration;
   let processor: PollingProcessor;
   let initSuccessHandler: jest.Mock;
 
   beforeEach(() => {
     store = new InMemoryFeatureStore();
     storeFacade = new AsyncStoreFacade(store);
-    config = new Configuration({
-      featureStore: store,
-      pollInterval: longInterval,
-      logger: new TestLogger(),
-    });
     initSuccessHandler = jest.fn();
 
     processor = new PollingProcessor(
-      config,
       requestor as unknown as Requestor,
-      config.featureStoreFactory(new ClientContext('', config, createBasicPlatform())),
+      longInterval,
+      store,
+      new TestLogger(),
       initSuccessHandler,
     );
   });
@@ -99,27 +90,22 @@ describe('given a polling processor with a short poll duration', () => {
   const jsonData = JSON.stringify(allData);
 
   let store: LDFeatureStore;
-  let config: Configuration;
+  let testLogger: TestLogger;
   let processor: PollingProcessor;
   let initSuccessHandler: jest.Mock;
   let errorHandler: jest.Mock;
 
   beforeEach(() => {
     store = new InMemoryFeatureStore();
-    config = new Configuration({
-      featureStore: store,
-      pollInterval: shortInterval,
-      logger: new TestLogger(),
-    });
+    testLogger = new TestLogger();
     initSuccessHandler = jest.fn();
     errorHandler = jest.fn();
 
-    // Configuration will not let us set this as low as needed for the test.
-    Object.defineProperty(config, 'pollInterval', { value: 0.1 });
     processor = new PollingProcessor(
-      config,
       requestor as unknown as Requestor,
-      config.featureStoreFactory(new ClientContext('', config, createBasicPlatform())),
+      shortInterval,
+      store,
+      testLogger,
       initSuccessHandler,
       errorHandler,
     );
@@ -130,14 +116,21 @@ describe('given a polling processor with a short poll duration', () => {
     jest.resetAllMocks();
   });
 
-  it('polls repeatedly', (done) => {
-    requestor.requestAllData = jest.fn((cb) => cb(undefined, jsonData));
+  it('polls repeatedly', async () => {
+    const expectedCalls = new Promise<void>((resolve) => {
+      let callCount = 0;
+      requestor.requestAllData = jest.fn((cb) => {
+        cb(undefined, jsonData);
+        callCount += 1;
+        if (callCount >= 10) {
+          resolve();
+        }
+      });
 
-    processor.start();
-    setTimeout(() => {
-      expect(requestor.requestAllData.mock.calls.length).toBeGreaterThanOrEqual(4);
-      done();
-    }, 500);
+      processor.start();
+    });
+
+    await expectedCalls;
   });
 
   it.each<number | jest.DoneCallback>([400, 408, 429, 500, 503])(
@@ -158,7 +151,6 @@ describe('given a polling processor with a short poll duration', () => {
       expect(errorHandler).not.toBeCalled();
       setTimeout(() => {
         expect(requestor.requestAllData.mock.calls.length).toBeGreaterThanOrEqual(2);
-        const testLogger = config.logger as TestLogger;
         expect(testLogger.getCount(LogLevel.Error)).toBe(0);
         expect(testLogger.getCount(LogLevel.Warn)).toBeGreaterThan(2);
         (done as jest.DoneCallback)();
@@ -176,7 +168,6 @@ describe('given a polling processor with a short poll duration', () => {
 
     setTimeout(() => {
       expect(requestor.requestAllData.mock.calls.length).toBeGreaterThanOrEqual(2);
-      const testLogger = config.logger as TestLogger;
       expect(testLogger.getCount(LogLevel.Error)).toBeGreaterThan(2);
       (done as jest.DoneCallback)();
     }, 300);
@@ -199,7 +190,6 @@ describe('given a polling processor with a short poll duration', () => {
 
       setTimeout(() => {
         expect(requestor.requestAllData.mock.calls.length).toBe(1);
-        const testLogger = config.logger as TestLogger;
         expect(testLogger.getCount(LogLevel.Error)).toBe(1);
         (done as jest.DoneCallback)();
       }, 300);