Adds helper function for getting NRestarts

README.md

@@ -34,6 +34,7 @@ In fact, if `systemctl` isn't found in the `PATH`, this library will panic.
 - [x] Get start time of a service (`ExecMainStartTimestamp`) as a `Time` type
 - [x] Get current memory in bytes (`MemoryCurrent`) an an int
 - [x] Get the PID of the main process (`MainPID`) as an int
+- [x] Get the restart count of a unit (`NRestarts`) as an int
 
 
 ## Useful errors
@@ -45,10 +46,6 @@ All functions return a predefined error type, and it is highly recommended these
 All calls into this library support go's `context` functionality.
 Therefore, blocking calls can time out according to the caller's needs, and the returned error should be checked to see if a timeout occurred (`ErrExecTimeout`).
 
-## TODO
-
-- [ ] Set up `go test` testing
-- [ ] Document each function using `godoc` standards
 
 ## Simple example
 

helpers.go

@@ -24,6 +24,15 @@ func GetStartTime(ctx context.Context, unit string, opts Options) (time.Time, er
 	return time.Parse(dateFormat, value)
 }
 
+// Get the number of times a process restarted (`systemctl show [unit] --property NRestarts`) as an int
+func GetNumRestarts(ctx context.Context, unit string, opts Options) (int, error) {
+	value, err := Show(ctx, unit, properties.NRestarts, opts)
+	if err != nil {
+		return -1, err
+	}
+	return strconv.Atoi(value)
+}
+
 // Get current memory in bytes (`systemctl show [unit] --property MemoryCurrent`) an an int
 func GetMemoryUsage(ctx context.Context, unit string, opts Options) (int, error) {
 	value, err := Show(ctx, unit, properties.MemoryCurrent, opts)

helpers_test.go

@@ -3,6 +3,7 @@ package systemctl
 import (
 	"context"
 	"fmt"
+	"syscall"
 	"testing"
 	"time"
 )
@@ -80,6 +81,83 @@ func TestGetStartTime(t *testing.T) {
 		}
 	})
 
+}
+func TestGetNumRestarts(t *testing.T) {
+	testCases := []struct {
+		unit      string
+		err       error
+		opts      Options
+		runAsUser bool
+	}{
+		// Run these tests only as a user
+
+		//try nonexistant unit in user mode as user
+		{"nonexistant", ErrValueNotSet, Options{UserMode: false}, true},
+		// try existing unit in user mode as user
+		{"syncthing", ErrValueNotSet, Options{UserMode: true}, true},
+		// try existing unit in system mode as user
+		{"nginx", nil, Options{UserMode: false}, true},
+
+		// Run these tests only as a superuser
+
+		// try nonexistant unit in system mode as system
+		{"nonexistant", ErrValueNotSet, Options{UserMode: false}, false},
+		// try existing unit in system mode as system
+		{"nginx", ErrBusFailure, Options{UserMode: true}, false},
+		// try existing unit in system mode as system
+		{"nginx", nil, Options{UserMode: false}, false},
+	}
+	for _, tc := range testCases {
+		t.Run(fmt.Sprintf("%s as %s", tc.unit, userString), func(t *testing.T) {
+			t.Parallel()
+			if (userString == "root" || userString == "system") && tc.runAsUser {
+				t.Skip("skipping user test while running as superuser")
+			} else if (userString != "root" && userString != "system") && !tc.runAsUser {
+				t.Skip("skipping superuser test while running as user")
+			}
+			ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
+			defer cancel()
+			_, err := GetNumRestarts(ctx, tc.unit, tc.opts)
+			if err != tc.err {
+				t.Errorf("error is %v, but should have been %v", err, tc.err)
+			}
+		})
+	}
+	// Prove restart count increases by one after a restart
+	t.Run(fmt.Sprintf("prove restart count increases by one after a restart"), func(t *testing.T) {
+		if userString != "root" && userString != "system" {
+			t.Skip("skipping superuser test while running as user")
+		}
+
+		ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+		defer cancel()
+		restarts, err := GetNumRestarts(ctx, "nginx", Options{UserMode: false})
+		if err != nil {
+			t.Errorf("issue getting number of restarts for nginx: %v", err)
+		}
+		pid, err := GetPID(ctx, "nginx", Options{UserMode: false})
+		if err != nil {
+			t.Errorf("issue getting MainPID for nginx as %s: %v", userString, err)
+		}
+		syscall.Kill(pid, syscall.SIGKILL)
+		for {
+			running, err := IsActive(ctx, "nginx", Options{UserMode: false})
+			if err != nil {
+				t.Errorf("error asserting nginx is up: %v", err)
+				break
+			} else if running {
+				break
+			}
+		}
+		secondRestarts, err := GetNumRestarts(ctx, "nginx", Options{UserMode: false})
+		if err != nil {
+			t.Errorf("issue getting second reading on number of restarts for nginx: %v", err)
+		}
+		if restarts+1 != secondRestarts {
+			t.Errorf("Expected restart count to differ by one, but difference was: %d", secondRestarts-restarts)
+		}
+	})
+
 }
 
 func TestGetMemoryUsage(t *testing.T) {
@@ -123,7 +201,7 @@ func TestGetMemoryUsage(t *testing.T) {
 			}
 		})
 	}
-	// Prove start time changes after a restart
+	// Prove memory usage values change across services
 	t.Run(fmt.Sprintf("prove memory usage values change across services"), func(t *testing.T) {
 		ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
 		defer cancel()
@@ -133,12 +211,11 @@ func TestGetMemoryUsage(t *testing.T) {
 		}
 		secondBytes, err := GetMemoryUsage(ctx, "user.slice", Options{UserMode: false})
 		if err != nil {
-			t.Errorf("issue getting second memort usage reading of nginx: %v", err)
+			t.Errorf("issue getting second memory usage reading of nginx: %v", err)
 		}
 		if bytes == secondBytes {
 			t.Errorf("Expected memory usage between nginx and user.slice to differ, but both were: %d", bytes)
 		}
-		t.Parallel()
 	})
 
 }
@@ -184,6 +261,3 @@ func TestGetPID(t *testing.T) {
 		})
 	}
 }
-
-// GetMemoryUsage(ctx context.Context, unit string, opts Options) (int, error) {
-// GetPID(ctx context.Context, unit string, opts Options) (int, error) {

systemctl.go

@@ -62,15 +62,19 @@ func IsActive(ctx context.Context, unit string, opts Options) (bool, error) {
 		args[1] = "--user"
 	}
 	stdout, _, _, err := execute(ctx, args)
-	if matched, _ := regexp.MatchString(`inactive`, stdout); matched {
+	stdout = strings.TrimSuffix(stdout, "\n")
+	switch stdout {
+	case "inactive":
 		return false, nil
-	} else if matched, _ := regexp.MatchString(`active`, stdout); matched {
+	case "active":
 		return true, nil
-	} else if matched, _ := regexp.MatchString(`failed`, stdout); matched {
+	case "failed":
 		return false, nil
-	}
+	case "activating":
-
+		return false, nil
+	default:
 		return false, err
+	}
 }
 
 // Checks whether any of the specified unit files are enabled (as with enable).
@@ -88,6 +92,7 @@ func IsEnabled(ctx context.Context, unit string, opts Options) (bool, error) {
 		args[1] = "--user"
 	}
 	stdout, _, _, err := execute(ctx, args)
+	stdout = strings.TrimSuffix(stdout, "\n")
 	switch stdout {
 	case "enabled":
 		return true, nil