Add once background status

internal/command/background.go

@@ -15,6 +15,7 @@ func newBackgroundCommand() *backgroundCommand {
 
 	b.cmd.AddCommand(newBackgroundInstallCommand().cmd)
 	b.cmd.AddCommand(newBackgroundUninstallCommand().cmd)
+	b.cmd.AddCommand(newBackgroundStatusCommand().cmd)
 	b.cmd.AddCommand(newBackgroundRunCommand().cmd)
 
 	return b

internal/command/background_status.go

@@ -0,0 +1,62 @@
+package command
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/spf13/cobra"
+
+	"github.com/basecamp/once/internal/service"
+)
+
+type backgroundStatusCommand struct {
+	cmd *cobra.Command
+}
+
+func newBackgroundStatusCommand() *backgroundStatusCommand {
+	b := &backgroundStatusCommand{}
+	b.cmd = &cobra.Command{
+		Use:   "status",
+		Short: "Show whether the background tasks service is installed and running",
+		Args:  cobra.NoArgs,
+		RunE:  b.run,
+	}
+	return b
+}
+
+// Private
+
+func (b *backgroundStatusCommand) run(cmd *cobra.Command, args []string) error {
+	ctx := context.Background()
+	namespace := namespaceFlag(cmd)
+
+	svc, err := service.New()
+	if err != nil {
+		return err
+	}
+
+	serviceName := namespace + backgroundServiceSuffix
+
+	switch {
+	case !svc.IsInstalled(serviceName):
+		fmt.Printf("Service %s is not installed\n", svc.ServiceName(serviceName))
+	case svc.IsRunning(ctx, serviceName):
+		fmt.Printf("Service %s is installed and running\n", svc.ServiceName(serviceName))
+		return nil
+	default:
+		fmt.Printf("Service %s is installed but not running\n", svc.ServiceName(serviceName))
+	}
+
+	cmd.SilenceErrors = true
+	return notRunningError{}
+}
+
+type notRunningError struct{}
+
+func (notRunningError) Error() string {
+	return "service is not running"
+}
+
+func (notRunningError) ExitCode() int {
+	return 3
+}

internal/service/launchd.go

@@ -46,6 +46,10 @@ func (l *Launchd) IsInstalled(name string) bool {
 	return err == nil
 }
 
+func (l *Launchd) IsRunning(ctx context.Context, name string) bool {
+	return exec.CommandContext(ctx, "launchctl", "print", "system/"+l.label(name)).Run() == nil
+}
+
 func (l *Launchd) Install(ctx context.Context, name, execPath, namespace string) error {
 	label := l.label(name)
 	path := l.plistPath(name)

internal/service/service.go

@@ -8,6 +8,7 @@ import (
 
 type Service interface {
 	IsInstalled(name string) bool
+	IsRunning(ctx context.Context, name string) bool
 	Install(ctx context.Context, name, execPath, namespace string) error
 	Remove(ctx context.Context, name string) error
 	ServiceName(name string) string

internal/service/systemd.go

@@ -33,6 +33,10 @@ func (s *Systemd) IsInstalled(name string) bool {
 	return err == nil
 }
 
+func (s *Systemd) IsRunning(ctx context.Context, name string) bool {
+	return exec.CommandContext(ctx, "systemctl", "is-active", "--quiet", name).Run() == nil
+}
+
 func (s *Systemd) Install(ctx context.Context, name, execPath, namespace string) error {
 	path := s.unitFilePath(name)