make restart code a bit more idiomatic

pkg/containerd/restart.go

@@ -42,27 +42,24 @@ func (c *Config) RestartRuntime() error {
 }
 
 func getPid() (int, error) {
-	processList, err := psProcesses()
+	processes, err := psProcesses()
 	if err != nil {
 		slog.Info("psProcesses() Failed, are you using windows?")
-		return -1, fmt.Errorf("could not get processes: %+v", err)
+		return 0, fmt.Errorf("could not get processes: %+v", err)
 	}
 
-	var containerdProcessList = []ps.Process{}
+	var containerdProcesses = []ps.Process{}
 
-	for x := range processList {
-		process := processList[x]
+	for _, process := range processes {
 		if process.Executable() == "containerd" {
-			containerdProcessList = append(containerdProcessList, process)
+			containerdProcesses = append(containerdProcesses, process)
 		}
 
 	}
 
-	if len(containerdProcessList) == 1 {
-		return containerdProcessList[0].Pid(), nil
-	} else if len(containerdProcessList) == 0 {
-		return -1, fmt.Errorf("no containerd process found")
+	if len(containerdProcesses) == 1 {
+		return containerdProcesses[0].Pid(), nil
 	} else {
-		panic("multiple containerd processes found")
+		return 0, fmt.Errorf("need exactly one containerd process, found: %d", len(containerdProcesses))
 	}
 }

pkg/containerd/restart_test.go

@@ -34,7 +34,7 @@ func Test_getPid(t *testing.T) {
 	}{
 		{"no containerd process found", func() ([]ps.Process, error) {
 			return []ps.Process{}, nil
-		}, -1, true},
+		}, 0, true},
 		{"single containerd process found", func() ([]ps.Process, error) {
 			return []ps.Process{
 				&mockProcess{executable: "containerd", pid: 123},
@@ -48,7 +48,7 @@ func Test_getPid(t *testing.T) {
 		}, 0, true},
 		{"error getting processes", func() ([]ps.Process, error) {
 			return nil, fmt.Errorf("error getting processes")
-		}, -1, true},
+		}, 0, true},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {