feat: add createMetadataHook to set request tracing info (#32)

src/client/API.ts

@@ -18,18 +18,26 @@ import { Metadata } from '@grpc/grpc-js';
 import { KV, RequestWithMeta, Map } from '../types/common';
 import { mergeMetadataToMap } from '../utils';
 
+export type CreateMetadataHook = (localStorage?: AsyncLocalStorage<any>) => Record<string, string>;
+
 export interface APIOptions {
   logger?: Console;
   localStorage?: AsyncLocalStorage<any>;
+  /**
+   * Setting more request metadata here, e.g.: tracing headers
+   */
+  createMetadataHook?: CreateMetadataHook;
 }
 
 export class API {
   protected readonly localStorage?: AsyncLocalStorage<any>;
   protected readonly logger: Console;
+  #createMetadataHook?: CreateMetadataHook;
 
   constructor(options?: APIOptions) {
     this.localStorage = options?.localStorage;
     this.logger = options?.logger ?? global.console;
+    this.#createMetadataHook = options?.createMetadataHook;
   }
 
   createMetadata(request: RequestWithMeta<{}>, defaultRequestMeta?: Record<string, string>): Metadata {
@@ -45,6 +53,13 @@ export class API {
         metadata.add(key, request.requestMeta[key]);
       }
     }
+
+    if (this.#createMetadataHook) {
+      const moreMetadata = this.#createMetadataHook(this.localStorage);
+      for (const key in moreMetadata) {
+        metadata.add(key, moreMetadata[key]);
+      }
+    }
     return metadata;
   }
 

src/client/Client.ts

@@ -30,6 +30,7 @@ import File from './File';
 import Binding from './Binding';
 import Oss, { OssOptions } from './Oss';
 import Cryption, { CryptionOptions } from './Cryption';
+import type { CreateMetadataHook } from './API';
 
 const debug = debuglog('layotto:client:main');
 
@@ -39,13 +40,15 @@ export interface ClientOptions {
   cryption?: CryptionOptions;
   logger?: Console;
   localStorage?: AsyncLocalStorage<any>;
+  createMetadataHook?: CreateMetadataHook;
 }
 
 export default class Client {
   readonly host: string;
   readonly port: string;
   protected readonly localStorage?: AsyncLocalStorage<any>;
   protected readonly logger: Console;
+  protected readonly createMetadataHook?: CreateMetadataHook;
   protected readonly _runtime: RuntimeClient;
   private readonly _address: string;
   private readonly _ossClient: ObjectStorageServiceClient;
@@ -77,6 +80,7 @@ export default class Client {
     this._address = address;
     this.localStorage = options?.localStorage;
     this.logger = options?.logger ?? global.console;
+    this.createMetadataHook = options?.createMetadataHook;
     const clientCredentials = ChannelCredentials.createInsecure();
     this._runtime = new RuntimeClient(this._address, clientCredentials);
     debug('Start connection to %o', this._address);
@@ -94,6 +98,7 @@ export default class Client {
     return {
       localStorage: this.localStorage,
       logger: this.logger,
+      createMetadataHook: this.createMetadataHook,
     };
   }
 

test/unit/client/Client.test.ts

@@ -14,6 +14,7 @@
  */
 import { strict as assert } from 'node:assert';
 import { Client } from '../../../src';
+import { CreateMetadataHook } from '../../../src/client/API';
 import { CustomClient } from './fixtures/CustomClient';
 
 describe('client/Client.test.ts', () => {
@@ -34,8 +35,16 @@ describe('client/Client.test.ts', () => {
   describe('custom Client', () => {
     let customClient: CustomClient;
     beforeAll(() => {
+      const createMetadataHook: CreateMetadataHook = localStorage => {
+        return {
+          'x-localStorage': localStorage?.getStore() ?? 'not-exists',
+          'x-foo': 'bar',
+        };
+      };
+
       customClient = new CustomClient({
         logger: console,
+        createMetadataHook,
       });
     });