add userAbsent code

ingredients/user/userAbsent.go

@@ -0,0 +1,50 @@
+package user
+
+import (
+	"context"
+	"errors"
+	"os/exec"
+
+	"github.com/gogrlx/grlx/types"
+)
+
+func (u User) absent(ctx context.Context, test bool) (types.Result, error) {
+	var result types.Result
+	result.Succeeded = true
+	result.Failed = false
+	userName, ok := u.params["name"].(string)
+	if !ok {
+		result.Failed = true
+		result.Succeeded = false
+		return result, errors.New("invalid user; name must be a string")
+	}
+	if userExists(userName) {
+		if test {
+			return types.Result{
+				Succeeded: true,
+				Failed:    false,
+				Notes:     append(result.Notes, types.SimpleNote("user "+userName+" would be deleted")),
+			}, nil
+		}
+		cmd := exec.CommandContext(ctx, "userdel", userName)
+		err := cmd.Run()
+		if err != nil {
+			result.Failed = true
+			result.Succeeded = false
+			result.Notes = append(result.Notes, types.SimpleNote("user "+userName+" could not be deleted"))
+			result.Notes = append(result.Notes, types.SimpleNote(err.Error()))
+			return result, err
+		}
+		if !userExists(userName) {
+			result.Notes = append(result.Notes, types.SimpleNote("user "+userName+" deleted"))
+			return result, nil
+		}
+		result.Failed = true
+		result.Succeeded = false
+		result.Notes = append(result.Notes, types.SimpleNote("user "+userName+" could not be deleted"))
+		return result, errors.New("user " + userName + " could not be deleted")
+
+	}
+	result.Notes = append(result.Notes, types.SimpleNote("user "+userName+" already absent, nothing to do"))
+	return result, nil
+}