Add ability to specify capabilities in setup (#255)

and clarify that setup options are merged instead of replaced.

src/InvocationModel.ts

@@ -24,7 +24,7 @@ import { AzFuncSystemError } from './errors';
 import { waitForProxyRequest } from './http/httpProxy';
 import { createStreamRequest } from './http/HttpRequest';
 import { InvocationContext } from './InvocationContext';
-import { isHttpStreamEnabled } from './setup';
+import { enableHttpStream } from './setup';
 import { isHttpTrigger, isTimerTrigger, isTrigger } from './utils/isTrigger';
 import { isDefined, nonNullProp, nonNullValue } from './utils/nonNull';
 
@@ -76,7 +76,7 @@ export class InvocationModel implements coreTypes.InvocationModel {
                 const bindingType = rpcBinding.type;
 
                 let input: unknown;
-                if (isHttpTrigger(bindingType) && isHttpStreamEnabled()) {
+                if (isHttpTrigger(bindingType) && enableHttpStream) {
                     const proxyRequest = await waitForProxyRequest(this.#coreCtx.invocationId);
                     input = createStreamRequest(proxyRequest, nonNullProp(req, 'triggerMetadata'));
                 } else {

src/ProgrammingModel.ts

@@ -6,7 +6,7 @@ import { CoreInvocationContext, WorkerCapabilities } from '@azure/functions-core
 import { version } from './constants';
 import { setupHttpProxy } from './http/httpProxy';
 import { InvocationModel } from './InvocationModel';
-import { isHttpStreamEnabled, lockSetup } from './setup';
+import { capabilities as libraryCapabilities, enableHttpStream, lockSetup } from './setup';
 
 export class ProgrammingModel implements coreTypes.ProgrammingModel {
     name = '@azure/functions';
@@ -16,14 +16,16 @@ export class ProgrammingModel implements coreTypes.ProgrammingModel {
         return new InvocationModel(coreCtx);
     }
 
-    async getCapabilities(capabilities: WorkerCapabilities): Promise<WorkerCapabilities> {
+    async getCapabilities(workerCapabilities: WorkerCapabilities): Promise<WorkerCapabilities> {
         lockSetup();
 
-        if (isHttpStreamEnabled()) {
+        if (enableHttpStream) {
             const httpUri = await setupHttpProxy();
-            capabilities.HttpUri = httpUri;
+            workerCapabilities.HttpUri = httpUri;
         }
 
-        return capabilities;
+        Object.assign(workerCapabilities, libraryCapabilities);
+
+        return workerCapabilities;
     }
 }

src/converters/toRpcHttp.ts

@@ -5,7 +5,7 @@ import { RpcHttpData, RpcTypedData } from '@azure/functions-core';
 import { AzFuncSystemError } from '../errors';
 import { sendProxyResponse } from '../http/httpProxy';
 import { HttpResponse } from '../http/HttpResponse';
-import { isHttpStreamEnabled } from '../setup';
+import { enableHttpStream } from '../setup';
 import { toRpcHttpCookie } from './toRpcHttpCookie';
 import { toRpcTypedData } from './toRpcTypedData';
 
@@ -19,7 +19,7 @@ export async function toRpcHttp(invocationId: string, data: unknown): Promise<Rp
     }
 
     const response = data instanceof HttpResponse ? data : new HttpResponse(data);
-    if (isHttpStreamEnabled()) {
+    if (enableHttpStream) {
         // send http data over http proxy instead of rpc
         await sendProxyResponse(invocationId, response);
         return;

src/setup.ts

@@ -3,16 +3,18 @@
 
 import { SetupOptions } from '../types';
 import { AzFuncSystemError } from './errors';
+import { isDefined } from './utils/nonNull';
 import { tryGetCoreApiLazy } from './utils/tryGetCoreApiLazy';
 import { workerSystemLog } from './utils/workerSystemLog';
 
-let options: SetupOptions = {};
 let setupLocked = false;
-
 export function lockSetup(): void {
     setupLocked = true;
 }
 
+export let enableHttpStream = false;
+export const capabilities: Record<string, string> = {};
+
 export function setup(opts: SetupOptions): void {
     if (setupLocked) {
         throw new AzFuncSystemError("Setup options can't be changed after app startup has finished.");
@@ -27,10 +29,21 @@ export function setup(opts: SetupOptions): void {
         }
     }
 
-    options = opts;
-    workerSystemLog('information', `Setup options: ${JSON.stringify(options)}`);
-}
+    if (isDefined(opts.enableHttpStream)) {
+        enableHttpStream = opts.enableHttpStream;
+    }
 
-export function isHttpStreamEnabled(): boolean {
-    return !!options.enableHttpStream;
+    if (opts.capabilities) {
+        for (let [key, val] of Object.entries(opts.capabilities)) {
+            if (isDefined(val)) {
+                val = String(val);
+                workerSystemLog('debug', `Capability ${key} set to ${val}.`);
+                capabilities[key] = val;
+            }
+        }
+    }
+
+    if (enableHttpStream) {
+        workerSystemLog('debug', `HTTP streaming enabled.`);
+    }
 }

test/setup.test.ts

@@ -0,0 +1,46 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT License.
+
+import 'mocha';
+import { expect } from 'chai';
+import { capabilities, enableHttpStream, setup } from '../src/setup';
+
+describe('setup', () => {
+    it('enableHttpStream', () => {
+        // default
+        expect(enableHttpStream).to.equal(false);
+
+        // set to true
+        setup({ enableHttpStream: true });
+        expect(enableHttpStream).to.equal(true);
+
+        // don't change if not explicitly set
+        setup({});
+        expect(enableHttpStream).to.equal(true);
+        setup({ capabilities: {} });
+        expect(enableHttpStream).to.equal(true);
+
+        // set to false
+        setup({ enableHttpStream: false });
+        expect(enableHttpStream).to.equal(false);
+    });
+
+    it('capabilities', () => {
+        // default
+        expect(capabilities).to.deep.equal({});
+
+        // various setting & merging without replacing
+        setup({ capabilities: { a: '1' } });
+        expect(capabilities).to.deep.equal({ a: '1' });
+        setup({});
+        expect(capabilities).to.deep.equal({ a: '1' });
+        setup({ capabilities: { b: '2' } });
+        expect(capabilities).to.deep.equal({ a: '1', b: '2' });
+        setup({ capabilities: { a: '3' } });
+        expect(capabilities).to.deep.equal({ a: '3', b: '2' });
+
+        // boolean converted to string
+        setup({ capabilities: { c: true } });
+        expect(capabilities).to.deep.equal({ a: '3', b: '2', c: 'true' });
+    });
+});

types/app.d.ts

@@ -15,7 +15,8 @@ import { WarmupFunctionOptions } from './warmup';
 
 /**
  * Optional method to configure the behavior of your app.
- * This can only be done during app startup, before invocations occur
+ * This can only be done during app startup, before invocations occur.
+ * If called multiple times, options will be merged with the previous options specified.
  */
 export declare function setup(options: SetupOptions): void;
 

types/setup.d.ts

@@ -3,8 +3,14 @@
 
 export interface SetupOptions {
     /**
-     * PREVIEW: Stream http requests and responses instead of loading entire body in memory.
+     * Stream http requests and responses instead of loading entire body in memory.
      * [Learn more here](https://aka.ms/AzFuncNodeHttpStreams)
      */
     enableHttpStream?: boolean;
+
+    /**
+     * Dictionary of Node.js worker capabilities.
+     * This will be merged with existing capabilities specified by the Node.js worker and library.
+     */
+    capabilities?: Record<string, string | boolean>;
 }