client: add a StaticWatcher utility constructor

client/setec/static.go

@@ -0,0 +1,53 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package setec
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+)
+
+// StaticSecret returns a Secret that vends a static string value.
+// This is useful as a placeholder for development, migration, and testing.
+// The value reported by a static secret never changes.
+func StaticSecret(value string) Secret {
+	return func() []byte { return []byte(value) }
+}
+
+// StaticWatcher returns a Watcher that vends a static string value.
+// This is useful as a placeholder for development, migration, and testing.
+// The value reported by a static watcher never changes, and the watcher
+// channel is never ready.
+func StaticWatcher(value string) Watcher {
+	return Watcher{secret: StaticSecret(value)}
+}
+
+// StaticFile returns a Secret that vends the contents of path.  The contents
+// of the file are returned exactly as stored.
+//
+// This is useful as a placeholder for development, migration, and testing.
+// The value reported by this secret is the contents of path at the
+// time this function is called, and never changes.
+func StaticFile(path string) (Secret, error) {
+	bs, err := os.ReadFile(path)
+	if err != nil {
+		return nil, fmt.Errorf("reading static secret: %w", err)
+	}
+	return func() []byte { return bs }, nil
+}
+
+// StaticTextFile returns a secret that vends the contents of path, which are
+// treated as text with leading and trailing whitespace trimmed.
+//
+// This is useful as a placeholder for development, migration, and testing.
+// The value reported by a static secret never changes.
+func StaticTextFile(path string) (Secret, error) {
+	bs, err := os.ReadFile(path)
+	if err != nil {
+		return nil, fmt.Errorf("reading static secret: %w", err)
+	}
+	text := bytes.TrimSpace(bs)
+	return func() []byte { return text }, nil
+}

client/setec/store.go

@@ -4,15 +4,13 @@
 package setec
 
 import (
-	"bytes"
 	"context"
 	"encoding/json"
 	"errors"
 	"expvar"
 	"fmt"
 	"log"
 	"math/rand"
-	"os"
 	"sync"
 	"time"
 
@@ -492,41 +490,6 @@ func (s Secret) GetString() string {
 	return string(s())
 }
 
-// StaticSecret returns a Secret that vends a static string value.
-// This is useful as a placeholder for development, migration, and testing.
-// The value reported by a static secret never changes.
-func StaticSecret(value string) Secret {
-	return func() []byte { return []byte(value) }
-}
-
-// StaticFile returns a Secret that vends the contents of path.  The contents
-// of the file are returned exactly as stored.
-//
-// This is useful as a placeholder for development, migration, and testing.
-// The value reported by this secret is the contents of path at the
-// time this function is called, and never changes.
-func StaticFile(path string) (Secret, error) {
-	bs, err := os.ReadFile(path)
-	if err != nil {
-		return nil, fmt.Errorf("reading static secret: %w", err)
-	}
-	return func() []byte { return bs }, nil
-}
-
-// StaticTextFile returns a secret that vends the contents of path, which are
-// treated as text with leading and trailing whitespace trimmed.
-//
-// This is useful as a placeholder for development, migration, and testing.
-// The value reported by a static secret never changes.
-func StaticTextFile(path string) (Secret, error) {
-	bs, err := os.ReadFile(path)
-	if err != nil {
-		return nil, fmt.Errorf("reading static secret: %w", err)
-	}
-	text := bytes.TrimSpace(bs)
-	return func() []byte { return text }, nil
-}
-
 // hasExpired reports whether cs is an undeclared secret whose last access time
 // was longer ago than the expiry window.
 func (s *Store) hasExpired(cs *cachedSecret) bool {