feat: metadata upstream passing

src/microservice/transport/provider/grpc/index.ts

@@ -4,7 +4,7 @@ import { Logger } from 'winston';
 import type { Server as GRPCServer, ServiceImplementation } from 'nice-grpc';
 import type { CompatServiceDefinition } from 'nice-grpc/lib/service-definitions';
 import { createServer } from 'nice-grpc';
-import { loggingMiddleware, tracingMiddleware, WithRequestID } from './middlewares';
+import { loggingMiddleware, metaMiddleware, tracingMiddleware, WithRequestID } from './middlewares';
 
 /**
  * Name of the transport
@@ -50,6 +50,7 @@ export class Server {
 
     this.server = createServer()
       .use(tracingMiddleware)
+      .use(metaMiddleware)
       .use(loggingMiddleware(this.logger));
 
     this.name = NAME;

src/microservice/transport/provider/grpc/middlewares.ts

@@ -2,6 +2,8 @@ import { CallContext, ServerError, ServerMiddlewareCall } from 'nice-grpc';
 import { isAbortError } from 'abort-controller-x';
 import { Logger } from 'winston';
 import { v1 as uuidv1 } from 'uuid';
+import { metadataPassThrough } from '@restorecommerce/grpc-client/dist/middleware';
+import { AsyncLocalStorage } from 'async_hooks';
 
 const tracingHeader = 'x-request-id';
 
@@ -61,3 +63,37 @@ export const loggingMiddleware = (logger: Logger) => {
     }
   };
 };
+
+
+function bindAsyncGenerator<T = any, TReturn = any, TNext = any>(
+  store: AsyncLocalStorage<any>,
+  generator: AsyncGenerator<any, any, any>,
+): AsyncGenerator<T, TReturn, TNext> {
+  const ctx = store.getStore();
+  return {
+    next: () => store.run(ctx, generator.next.bind(generator)),
+    return: (args) => store.run(ctx, generator.return.bind(generator), args),
+    throw: (args) => store.run(ctx, generator.throw.bind(generator), args),
+
+    [Symbol.asyncIterator]() {
+      return this;
+    },
+  };
+}
+
+export async function* metaMiddleware<Request, Response>(
+  call: ServerMiddlewareCall<Request, Response>,
+  context: CallContext,
+) {
+  const mapped = {};
+  for (const [a, b] of context.metadata) {
+    mapped[a] = b;
+  }
+
+  const val = JSON.stringify(mapped);
+  metadataPassThrough.enterWith(val);
+
+  return yield* bindAsyncGenerator(metadataPassThrough, call.next(call.request, {
+    ...context,
+  }));
+}