admin listener as opt-in for initial config (#2834)

* Always cleanup admin endpoint first

* Error out if no config has been set (#2833)

* Ignore explicitly missing admin config (#2833)

* Separate config loading from admin initialization (#2833)

* Add admin option to specify admin listener address (#2833)

* Use zap for reporting admin endpoint status

1 files changed, 14 insertions, 2 deletions

diff --git a/cmd/commandfuncs.go b/cmd/commandfuncs.go
index 7c08c2e..d73644c 100644
--- a/cmd/commandfuncs.go
+++ b/cmd/commandfuncs.go
@@ -161,12 +161,24 @@ func cmdRun(fl Flags) (int, error) {
 	certmagic.UserAgent = "Caddy/" + cleanModVersion
 
 	// start the admin endpoint along with any initial config
+	// a configuration without admin config is considered fine
+	// but does not enable the admin endpoint at all
 	err = caddy.StartAdmin(config)
-	if err != nil {
+	if err == nil {
+		defer caddy.StopAdmin()
+	} else if err != caddy.ErrAdminInterfaceNotConfigured {
 		return caddy.ExitCodeFailedStartup,
 			fmt.Errorf("starting caddy administration endpoint: %v", err)
 	}
-	defer caddy.StopAdmin()
+
+	// if a config has been supplied, load it as initial config
+	if len(config) > 0 {
+		err := caddy.Load(bytes.NewReader(config))
+		if err != nil {
+			return caddy.ExitCodeFailedStartup, fmt.Errorf("loading initial config: %v", err)
+		}
+		caddy.Log().Named("admin").Info("Caddy 2 serving initial configuration")
+	}
 
 	// if we are to report to another process the successful start
 	// of the server, do so now by echoing back contents of stdin