Add Scheduled worker

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

@@ -22,3 +22,8 @@ export async function fetch(req, env, ctx) {
   await run();
   return handleRequest(req, { env, ctx });
 }
+
+export async function scheduled(event, env, ctx) {
+  await run();
+  return runScheduler(event, { env, ctx });
+}

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

@@ -3,4 +3,4 @@ import mod from "./app.wasm";
 
 imports.init(mod);
 
-export default { fetch: imports.fetch }
+export default { fetch: imports.fetch, scheduled: imports.scheduled }

cron.go

@@ -0,0 +1,84 @@
+package workers
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"syscall/js"
+	"time"
+
+	"github.com/syumai/workers/internal/jsutil"
+	"github.com/syumai/workers/internal/runtimecontext"
+)
+
+// CronEvent represents information about the Cron that invoked this worker.
+type CronEvent struct {
+	// Type string
+	Cron          string
+	ScheduledTime time.Time
+}
+
+// toGo converts JS Object to CronEvent
+func (ce *CronEvent) toGo(obj js.Value) error {
+	if obj.IsUndefined() {
+		return errors.New("event is null")
+	}
+	cronVal := obj.Get("cron").String()
+	ce.Cron = cronVal
+	scheduledTimeVal := obj.Get("scheduledTime").Float()
+	ce.ScheduledTime = time.Unix(int64(scheduledTimeVal)/1000, 0).UTC()
+
+	return nil
+}
+
+type CronFunc func(ctx context.Context, event CronEvent) error
+
+var cronTask CronFunc
+
+// ScheduleTask sets the CronFunc to be executed
+func ScheduleTask(task CronFunc) {
+	cronTask = task
+	jsutil.Global.Call("ready")
+	select {}
+}
+
+func runScheduler(eventObj js.Value, runtimeCtxObj js.Value) error {
+	ctx := runtimecontext.New(context.Background(), runtimeCtxObj)
+	event := CronEvent{}
+	err := event.toGo(eventObj)
+	if err != nil {
+		return err
+	}
+	err = cronTask(ctx, event)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func init() {
+	runSchedulerCallback := js.FuncOf(func(_ js.Value, args []js.Value) any {
+		if len(args) != 2 {
+			panic(fmt.Errorf("invalid number of arguments given to runScheduler: %d", len(args)))
+		}
+		event := args[0]
+		runtimeCtx := args[1]
+
+		var cb js.Func
+		cb = js.FuncOf(func(_ js.Value, pArgs []js.Value) any {
+			defer cb.Release()
+			resolve := pArgs[0]
+			go func() {
+				err := runScheduler(event, runtimeCtx)
+				if err != nil {
+					panic(err)
+				}
+				resolve.Invoke(js.Undefined())
+			}()
+			return js.Undefined()
+		})
+
+		return jsutil.NewPromise(cb)
+	})
+	jsutil.Global.Set("runScheduler", runSchedulerCallback)
+}

examples/cron/.gitignore

@@ -0,0 +1 @@
+build

examples/cron/Makefile

@@ -0,0 +1,12 @@
+.PHONY: dev
+dev:
+	wrangler dev
+
+.PHONY: build
+build:
+	go run ../../cmd/workers-assets-gen
+	tinygo build -o ./build/app.wasm -target wasm ./...
+
+.PHONY: publish
+publish:
+	wrangler publish

examples/cron/README.md

@@ -0,0 +1,20 @@
+# [Cron](https://developers.cloudflare.com/workers/platform/triggers/cron-triggers/)
+
+* Create a worker to be triggered by Cron.
+
+## Development
+
+### Requirements
+
+This project requires these tools to be installed globally.
+
+* wrangler
+* tinygo
+
+### Commands
+
+```
+make dev     # run dev server
+make build   # build Go Wasm binary
+make publish # publish worker
+```

examples/cron/go.mod

@@ -0,0 +1,7 @@
+module github.com/syumai/workers/examples/scheduled
+
+go 1.18
+
+require github.com/syumai/workers v0.0.0
+
+replace github.com/syumai/workers => ../../

examples/cron/main.go

@@ -0,0 +1,24 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	"github.com/syumai/workers"
+	"github.com/syumai/workers/cloudflare"
+)
+
+func task(ctx context.Context, event workers.CronEvent) error {
+	fmt.Println(cloudflare.Getenv(ctx, "HELLO"))
+
+	if event.ScheduledTime.Minute()%2 == 0 {
+		return errors.New("even numbers cause errors")
+	}
+
+	return nil
+}
+
+func main() {
+	workers.ScheduleTask(task)
+}

examples/cron/wrangler.toml

@@ -0,0 +1,13 @@
+name = "scheduled"
+main = "./build/worker.mjs"
+compatibility_date = "2023-02-24"
+workers_dev = false
+
+[vars]
+HELLO = "hello, world!"
+
+[triggers]
+crons = ["* * * * *"]
+
+[build]
+command = "make build"