cmd: Improve stop command by trying API before signaling process

This allows graceful shutdown on all platforms

cmd/commandfuncs.go

@@ -35,6 +35,7 @@ import (
 	"github.com/caddyserver/caddy/v2/caddyconfig"
 	"github.com/keybase/go-ps"
 	"github.com/mholt/certmagic"
+	"go.uber.org/zap"
 )
 
 func cmdStart(fl Flags) (int, error) {
@@ -193,19 +194,43 @@ func cmdRun(fl Flags) (int, error) {
 	select {}
 }
 
-func cmdStop(_ Flags) (int, error) {
+func cmdStop(fl Flags) (int, error) {
+	stopCmdAddrFlag := fl.String("address")
+
+	adminAddr := caddy.DefaultAdminListen
+	if stopCmdAddrFlag != "" {
+		adminAddr = stopCmdAddrFlag
+	}
+	stopEndpoint := fmt.Sprintf("http://%s/stop", adminAddr)
+
+	req, err := http.NewRequest(http.MethodPost, stopEndpoint, nil)
+	if err != nil {
+		return caddy.ExitCodeFailedStartup, fmt.Errorf("making request: %v", err)
+	}
+	req.Header.Set("Origin", adminAddr)
+
+	err = apiRequest(req)
+	if err != nil {
+		// if the caddy instance doesn't have an API listener set up,
+		// or we are unable to reach it for some reason, try signaling it
+
+		caddy.Log().Warn("unable to use API to stop instance; will try to signal the process",
+			zap.String("endpoint", stopEndpoint),
+			zap.Error(err),
+		)
+
 		processList, err := ps.Processes()
 		if err != nil {
 			return caddy.ExitCodeFailedStartup, fmt.Errorf("listing processes: %v", err)
 		}
 		thisProcName := getProcessName()
+
 		var found bool
 		for _, p := range processList {
-		// the process we're looking for should have the same name but different PID
+			// the process we're looking for should have the same name as us but different PID
 			if p.Executable() == thisProcName && p.Pid() != os.Getpid() {
 				found = true
 				fmt.Printf("pid=%d\n", p.Pid())
-
 				if err := gracefullyStopProcess(p.Pid()); err != nil {
 					return caddy.ExitCodeFailedStartup, err
 				}
@@ -214,7 +239,10 @@ func cmdStop(_ Flags) (int, error) {
 		if !found {
 			return caddy.ExitCodeFailedStartup, fmt.Errorf("Caddy is not running")
 		}
+
 		fmt.Println(" success")
+	}
+
 	return caddy.ExitCodeSuccess, nil
 }
 
@@ -251,25 +279,19 @@ func cmdReload(fl Flags) (int, error) {
 	if adminAddr == "" {
 		adminAddr = caddy.DefaultAdminListen
 	}
-	adminEndpoint := fmt.Sprintf("http://%s/load", adminAddr)
+	loadEndpoint := fmt.Sprintf("http://%s/load", adminAddr)
 
-	// send the configuration to the instance
+	// prepare the request to update the configuration
-	resp, err := http.Post(adminEndpoint, "application/json", bytes.NewReader(config))
+	req, err := http.NewRequest(http.MethodPost, loadEndpoint, bytes.NewReader(config))
 	if err != nil {
-		return caddy.ExitCodeFailedStartup,
+		return caddy.ExitCodeFailedStartup, fmt.Errorf("making request: %v", err)
-			fmt.Errorf("sending configuration to instance: %v", err)
 	}
-	defer resp.Body.Close()
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("Origin", adminAddr)
 
-	// if it didn't work, let the user know
+	err = apiRequest(req)
-	if resp.StatusCode >= 400 {
-		respBody, err := ioutil.ReadAll(io.LimitReader(resp.Body, 1024*10))
 	if err != nil {
-			return caddy.ExitCodeFailedStartup,
+		return caddy.ExitCodeFailedStartup, fmt.Errorf("sending configuration to instance: %v", err)
-				fmt.Errorf("HTTP %d: reading error message: %v", resp.StatusCode, err)
-		}
-		return caddy.ExitCodeFailedStartup,
-			fmt.Errorf("caddy responded with error: HTTP %d: %s", resp.StatusCode, respBody)
 	}
 
 	return caddy.ExitCodeSuccess, nil
@@ -522,3 +544,22 @@ commands:
 
 	return caddy.ExitCodeSuccess, nil
 }
+
+func apiRequest(req *http.Request) error {
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return fmt.Errorf("performing request: %v", err)
+	}
+	defer resp.Body.Close()
+
+	// if it didn't work, let the user know
+	if resp.StatusCode >= 400 {
+		respBody, err := ioutil.ReadAll(io.LimitReader(resp.Body, 1024*10))
+		if err != nil {
+			return fmt.Errorf("HTTP %d: reading error message: %v", resp.StatusCode, err)
+		}
+		return fmt.Errorf("caddy responded with error: HTTP %d: %s", resp.StatusCode, respBody)
+	}
+
+	return nil
+}

cmd/commands.go

@@ -134,11 +134,18 @@ not quit after printing, and can be useful for troubleshooting.`,
 		Long: `
 Stops the background Caddy process as gracefully as possible.
 
-On Windows, this stop is forceful and Caddy will not have an opportunity to
+It will first try to use the admin API's /stop endpoint; the address of
-clean up any active locks; for a graceful shutdown on Windows, use Ctrl+C
+this request can be customized using the --address flag if it is not the
-or the /stop API endpoint.
+default.
 
-Note: this will stop any process named the same as the executable (os.Args[0]).`,
+If that fails for any reason, it will attempt to signal the first process
+it can find named the same as this one (os.Args[0]). On Windows, such
+a stop is forceful because Windows does not have signals.`,
+		Flags: func() *flag.FlagSet {
+			fs := flag.NewFlagSet("stop", flag.ExitOnError)
+			fs.String("address", "", "The address to use to reach the admin API endpoint, if not the default")
+			return fs
+		}(),
 	})
 
 	RegisterCommand(Command{

cmd/proc_posix.go

@@ -24,7 +24,7 @@ import (
 )
 
 func gracefullyStopProcess(pid int) error {
-	fmt.Printf("Graceful stop...\n")
+	fmt.Print("Graceful stop... ")
 	err := syscall.Kill(pid, syscall.SIGINT)
 	if err != nil {
 		return fmt.Errorf("kill: %v", err)

cmd/proc_windows.go

@@ -23,7 +23,7 @@ import (
 )
 
 func gracefullyStopProcess(pid int) error {
-	fmt.Printf("Forceful Stop...\n")
+	fmt.Print("Forceful stop... ")
 	// process on windows will not stop unless forced with /f
 	cmd := exec.Command("taskkill", "/pid", strconv.Itoa(pid), "/f")
 	if err := cmd.Run(); err != nil {