feat: kill-server

Author: cfoust

cmd/cy/kill.go

@@ -0,0 +1,59 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+	"syscall"
+)
+
+func killServerCommand() error {
+	socketPath, err := getSocketPath(CLI.Socket)
+	if err != nil {
+		return fmt.Errorf(
+			"failed to detect socket path: %s",
+			err,
+		)
+	}
+
+	pidPath := getPidPath(socketPath)
+	data, err := os.ReadFile(pidPath)
+	if err != nil {
+		return fmt.Errorf(
+			"no server running (could not read %s)",
+			pidPath,
+		)
+	}
+
+	pid, err := strconv.Atoi(strings.TrimSpace(string(data)))
+	if err != nil {
+		return fmt.Errorf(
+			"invalid PID in %s: %s",
+			pidPath,
+			err,
+		)
+	}
+
+	process, err := os.FindProcess(pid)
+	if err != nil {
+		return fmt.Errorf(
+			"could not find process %d: %s",
+			pid,
+			err,
+		)
+	}
+
+	if err := process.Signal(syscall.SIGTERM); err != nil {
+		return fmt.Errorf(
+			"failed to kill server (pid %d): %s",
+			pid,
+			err,
+		)
+	}
+
+	_ = os.Remove(pidPath)
+	_ = os.Remove(socketPath)
+
+	return nil
+}

cmd/cy/main.go

@@ -31,6 +31,8 @@ var CLI struct {
 		CPU    string `help:"Save a CPU performance report to the given path." name:"perf-file" optional:"" default:""`
 		Trace  string `help:"Save a trace report to the given path." name:"trace-file" optional:"" default:""`
 	} `cmd:"" default:"1" aliases:"attach" help:"Connect to the cy server, starting one if necessary."`
+
+	KillServer struct{} `cmd:"" name:"kill-server" help:"Kill the cy server."`
 }
 
 func writeError(err error) {
@@ -113,5 +115,10 @@ func main() {
 		if err != nil {
 			writeError(err)
 		}
+	case "kill-server":
+		err := killServerCommand()
+		if err != nil {
+			writeError(err)
+		}
 	}
 }

cmd/cy/server.go

@@ -19,6 +19,10 @@ func getLockPath(socketPath string) string {
 	return socketPath + ".lock"
 }
 
+func getPidPath(socketPath string) string {
+	return socketPath + ".pid"
+}
+
 type Server struct {
 	cy *cy.Cy
 }
@@ -146,6 +150,16 @@ func getConfig() (string, error) {
 }
 
 func serve(path string) error {
+	pidPath := getPidPath(path)
+	if err := os.WriteFile(
+		pidPath,
+		[]byte(fmt.Sprintf("%d", os.Getpid())),
+		0600,
+	); err != nil {
+		return err
+	}
+	defer func() { _ = os.Remove(pidPath) }()
+
 	cwd, err := os.Getwd()
 	if err != nil {
 		return err