feat: Use SyncContext from GrpcFetch instead of Metadata Request

Signed-off-by: marcozabel <[email protected]>

Author: marcozabel

libs/providers/flagd/src/lib/SyncMetadataHook.ts

@@ -0,0 +1,13 @@
+import {Hook} from "@openfeature/web-sdk";
+
+export class SyncMetadataHook implements Hook<any> {
+  contextSupplier: () => { [key: string]: any } | null;
+
+  constructor(getContext: () => { [key: string]: any } | null) {
+    this.contextSupplier = getContext;
+  }
+
+  public before(): any {
+    return this.contextSupplier();
+  }
+}

libs/providers/flagd/src/lib/flagd-provider.ts

@@ -5,14 +5,18 @@ import { getConfig } from './configuration';
 import { GRPCService } from './service/grpc/grpc-service';
 import type { Service } from './service/service';
 import { InProcessService } from './service/in-process/in-process-service';
+import { Hook } from "@openfeature/web-sdk";
+import { SyncMetadataHook } from "./SyncMetadataHook";
 
 export class FlagdProvider implements Provider {
   metadata = {
     name: 'flagd',
   };
 
+  readonly hooks: Hook[] = [];
   readonly runsOn = 'server';
   readonly events = new OpenFeatureEventEmitter();
+  private syncContext: { [key: string]: any } | null = null;
 
   private readonly _service: Service;
 
@@ -30,11 +34,27 @@ export class FlagdProvider implements Provider {
   ) {
     const config = getConfig(options);
 
-    this._service = service
-      ? service
-      : config.resolverType === 'in-process'
-        ? new InProcessService(config, undefined, logger)
-        : new GRPCService(config, undefined, logger);
+    if (service === undefined) {
+      if (config.resolverType === "in-process") {
+        this._service = new InProcessService(config, this.setSyncContext, undefined, logger);
+
+        if (config?.offlineFlagSourcePath === undefined) {
+          this.hooks.push(new SyncMetadataHook(this.getSyncContext));
+        }
+      } else {
+        this._service = new GRPCService(config, undefined, logger);
+      }
+    } else {
+      this._service = service;
+    }
+  }
+
+  setSyncContext(context: {[key: string]: any}) {
+    this.syncContext = context;
+  }
+
+  getSyncContext(): {[key: string]: any} | null {
+    return this.syncContext;
   }
 
   async initialize(): Promise<void> {

libs/providers/flagd/src/lib/service/in-process/grpc/grpc-fetch.ts

@@ -15,6 +15,7 @@ export class GrpcFetch implements DataFetch {
   private readonly _syncClient: FlagSyncServiceClient;
   private readonly _request: SyncFlagsRequest;
   private _syncStream: ClientReadableStream<SyncFlagsResponse> | undefined;
+  private readonly _setSyncContext: (syncContext: { [key: string]: any }) => void;
   private _logger: Logger | undefined;
   /**
    * Initialized will be set to true once the initial connection is successful
@@ -29,7 +30,7 @@ export class GrpcFetch implements DataFetch {
    */
   private _isConnected = false;
 
-  constructor(config: Config, syncServiceClient?: FlagSyncServiceClient, logger?: Logger) {
+  constructor(config: Config, setSyncContext: (syncContext: {[key: string]: any }) => void, syncServiceClient?: FlagSyncServiceClient, logger?: Logger) {
     const { host, port, tls, socketPath, selector, defaultAuthority } = config;
     let clientOptions: ClientOptions | undefined;
     if (defaultAuthority) {
@@ -46,6 +47,7 @@ export class GrpcFetch implements DataFetch {
           clientOptions,
         );
 
+    this._setSyncContext = setSyncContext;
     this._logger = logger;
     this._request = { providerId: '', selector: selector ? selector : '' };
   }
@@ -84,6 +86,9 @@ export class GrpcFetch implements DataFetch {
         this._logger?.debug(`Received sync payload`);
 
         try {
+          if (data.syncContext) {
+            this._setSyncContext(data.syncContext);
+          }
           const changes = dataCallback(data.flagConfiguration);
           if (this._initialized && changes.length > 0) {
             changedCallback(changes);

libs/providers/flagd/src/lib/service/in-process/in-process-service.ts

@@ -19,6 +19,7 @@ export class InProcessService implements Service {
 
   constructor(
     private readonly config: Config,
+    setSyncContext: (syncContext: { [key: string]: any }) => void,
     dataFetcher?: DataFetch,
     logger?: Logger,
   ) {
@@ -27,7 +28,7 @@ export class InProcessService implements Service {
       ? dataFetcher
       : config.offlineFlagSourcePath
         ? new FileFetch(config.offlineFlagSourcePath, logger)
-        : new GrpcFetch(config, undefined, logger);
+        : new GrpcFetch(config, setSyncContext, undefined, logger);
   }
 
   connect(