snapshot of https://github.com/ory/kratos.git (master, 2026-09-15; blobs > 131072B omitted)

oryx/watcherx/definitions.go

@@ -0,0 +1,78 @@
+// Copyright © 2023 Ory Corp
+// SPDX-License-Identifier: Apache-2.0
+
+package watcherx
+
+import (
+	"context"
+	"fmt"
+	"net/url"
+
+	"github.com/pkg/errors"
+)
+
+type (
+	errSchemeUnknown struct {
+		scheme string
+	}
+	EventChannel chan Event
+	Watcher      interface {
+		// DispatchNow fires the watcher and causes an event.
+		//
+		// WARNING: The returned channel must be read or no further events will
+		// be propagated due to a deadlock.
+		DispatchNow() (<-chan int, error)
+	}
+	dispatcher struct {
+		ctx     context.Context
+		trigger chan struct{}
+		done    chan int
+	}
+)
+
+var (
+	// ErrSchemeUnknown is just for checking with errors.Is()
+	ErrSchemeUnknown     = &errSchemeUnknown{}
+	ErrWatcherNotRunning = fmt.Errorf("watcher is not running")
+)
+
+func (e *errSchemeUnknown) Is(other error) bool {
+	_, ok := other.(*errSchemeUnknown)
+	return ok
+}
+
+func (e *errSchemeUnknown) Error() string {
+	return fmt.Sprintf("unknown scheme '%s' to watch", e.scheme)
+}
+
+func newDispatcher(ctx context.Context) *dispatcher {
+	return &dispatcher{
+		ctx:     ctx,
+		trigger: make(chan struct{}),
+		done:    make(chan int),
+	}
+}
+
+func (d *dispatcher) DispatchNow() (<-chan int, error) {
+	if d.trigger == nil {
+		return nil, ErrWatcherNotRunning
+	}
+	// The trigger send must respect cancellation. Once the watcher's context is
+	// done its receiver goroutine has returned, so a bare send would block
+	// forever and wedge the caller.
+	select {
+	case d.trigger <- struct{}{}:
+		return d.done, nil
+	case <-d.ctx.Done():
+		return nil, errors.WithStack(ErrWatcherNotRunning)
+	}
+}
+
+func Watch(ctx context.Context, u *url.URL, c EventChannel) (Watcher, error) {
+	switch u.Scheme {
+	// see urlx.Parse for why the empty string is also file
+	case "file", "":
+		return WatchFile(ctx, u.Path, c)
+	}
+	return nil, &errSchemeUnknown{u.Scheme}
+}