pass RuntimeContext on create Go instance

cloudflare/cron/cron.go

@@ -78,5 +78,5 @@ func init() {
 
 		return jsutil.NewPromise(cb)
 	})
-	js.Global().Set("runScheduler", runSchedulerCallback)
+	jsutil.Binding.Set("runScheduler", runSchedulerCallback)
 }

cmd/workers-assets-gen/assets/common/shim.mjs

@@ -21,7 +21,7 @@ export function init(m) {
   mod = m;
 }
 
-async function run() {
+async function run(ctx) {
   let ready;
   const readyPromise = new Promise((resolve) => {
     ready = resolve;
@@ -32,31 +32,35 @@ async function run() {
       ready: () => { ready() }
     },
   });
-  go.run(instance);
+  go.run(instance, ctx);
   await readyPromise;
 }
 
-function createRuntimeContext(env, ctx) {
+function createRuntimeContext(env, ctx, binding) {
   return {
     env,
     ctx,
     connect,
+    binding,
   };
 }
 
 export async function fetch(req, env, ctx) {
-  await run();
-  return handleRequest(req, createRuntimeContext(env, ctx));
+  const binding = {};
+  await run(createRuntimeContext(env, ctx, binding));
+  return binding.handleRequest(req);
 }
 
 export async function scheduled(event, env, ctx) {
-  await run();
-  return runScheduler(event, createRuntimeContext(env, ctx));
+  const binding = {};
+  await run(createRuntimeContext(env, ctx, binding));
+  return binding.runScheduler(event);
 }
 
 // onRequest handles request to Cloudflare Pages
 export async function onRequest(ctx) {
-  await run();
+  const binding = {};
   const { request, env } = ctx;
-  return handleRequest(request, createRuntimeContext(env, ctx));
+  await run(createRuntimeContext(env, ctx, binding));
+  return binding.handleRequest(request);
 }

cmd/workers-assets-gen/assets/wasm_exec_go.js

@@ -462,19 +462,27 @@
 			};
 		}
 
-		async run(instance) {
+		async run(instance, context) {
 			if (!(instance instanceof WebAssembly.Instance)) {
 				throw new Error("Go.run: WebAssembly.Instance expected");
 			}
 			this._inst = instance;
 			this.mem = new DataView(this._inst.exports.mem.buffer);
+			const globalProxy = new Proxy(globalThis, {
+				get(target, prop) {
+					if (prop === 'context') {
+						return context;
+					}
+					return Reflect.get(...arguments);
+				}
+			})
 			this._values = [ // JS values that Go currently has references to, indexed by reference id
 				NaN,
 				0,
 				null,
 				true,
 				false,
-				globalThis,
+				globalProxy,
 				this,
 			];
 			this._goRefCounts = new Array(this._values.length).fill(Infinity); // number of references that Go has to a JS value, indexed by reference id

cmd/workers-assets-gen/assets/wasm_exec_tinygo.js

@@ -458,15 +458,23 @@
 			this.importObject.env = this.importObject.gojs;
 		}
 
-		async run(instance) {
+		async run(instance, context) {
 			this._inst = instance;
+			const globalProxy = new Proxy(global, {
+				get(target, prop) {
+					if (prop === 'context') {
+						return context;
+					}
+					return Reflect.get(...arguments);
+				}
+			})
 			this._values = [ // JS values that Go currently has references to, indexed by reference id
 				NaN,
 				0,
 				null,
 				true,
 				false,
-				global,
+				globalProxy,
 				this,
 			];
 			this._goRefCounts = []; // number of references that Go has to a JS value, indexed by reference id
@@ -513,25 +521,4 @@
 			};
 		}
 	}
-
-	if (
-		global.require &&
-		global.require.main === module &&
-		global.process &&
-		global.process.versions &&
-		!global.process.versions.electron
-	) {
-		if (process.argv.length != 3) {
-			console.error("usage: go_js_wasm_exec [wasm binary] [arguments]");
-			process.exit(1);
-		}
-
-		const go = new Go();
-		WebAssembly.instantiate(fs.readFileSync(process.argv[2]), go.importObject).then((result) => {
-			return go.run(result.instance);
-		}).catch((err) => {
-			console.error(err);
-			process.exit(1);
-		});
-	}
 })();

handler.go

@@ -17,14 +17,11 @@ var httpHandler http.Handler
 func init() {
 	var handleRequestCallback js.Func
 	handleRequestCallback = js.FuncOf(func(this js.Value, args []js.Value) any {
-		if len(args) > 2 {
+		if len(args) > 1 {
 			panic(fmt.Errorf("too many args given to handleRequest: %d", len(args)))
 		}
 		reqObj := args[0]
-		runtimeCtxObj := js.Null()
-		if len(args) > 1 {
-			runtimeCtxObj = args[1]
-		}
+		runtimeCtxObj := jsutil.RuntimeContext
 		var cb js.Func
 		cb = js.FuncOf(func(_ js.Value, pArgs []js.Value) any {
 			defer cb.Release()
@@ -40,7 +37,7 @@ func init() {
 		})
 		return jsutil.NewPromise(cb)
 	})
-	js.Global().Set("handleRequest", handleRequestCallback)
+	jsutil.Binding.Set("handleRequest", handleRequestCallback)
 }
 
 // handleRequest accepts a Request object and returns Response object.

internal/jsutil/jsutil.go

@@ -7,6 +7,8 @@ import (
 )
 
 var (
+	RuntimeContext      = js.Global().Get("context")
+	Binding             = js.Global().Get("context").Get("binding")
 	ObjectClass         = js.Global().Get("Object")
 	PromiseClass        = js.Global().Get("Promise")
 	RequestClass        = js.Global().Get("Request")