feat(client): Add ssh private-key support (#1390)

* feat(endpoint): Add ssh key support

Fixes #1257

* test(config): Add tests for private key config

---------

Co-authored-by: TwiN <twin@linux.com>

config/endpoint/condition.go

@@ -244,9 +244,7 @@ func formatDuration(d time.Duration) string {
 	if strings.HasSuffix(s, "0s") {
 		s = strings.TrimSuffix(s, "0s")
 		// Remove trailing "0m" if present after removing "0s"
-		if strings.HasSuffix(s, "0m") {
-			s = strings.TrimSuffix(s, "0m")
-		}
+		s = strings.TrimSuffix(s, "0m")
 	}
 	return s
 }

config/endpoint/endpoint.go

@@ -503,8 +503,8 @@ func (e *Endpoint) call(result *Result) {
 		}
 		result.Duration = time.Since(startTime)
 	} else if endpointType == TypeSSH {
-		// If there's no username/password specified, attempt to validate just the SSH banner
-		if e.SSHConfig == nil || (len(e.SSHConfig.Username) == 0 && len(e.SSHConfig.Password) == 0) {
+		// If there's no username, password or private key specified, attempt to validate just the SSH banner
+		if e.SSHConfig == nil || (len(e.SSHConfig.Username) == 0 && len(e.SSHConfig.Password) == 0 && len(e.SSHConfig.PrivateKey) == 0) {
 			result.Connected, result.HTTPStatus, err = client.CheckSSHBanner(strings.TrimPrefix(e.URL, "ssh://"), e.ClientConfig)
 			if err != nil {
 				result.AddError(err.Error())
@@ -515,7 +515,7 @@ func (e *Endpoint) call(result *Result) {
 			return
 		}
 		var cli *ssh.Client
-		result.Connected, cli, err = client.CanCreateSSHConnection(strings.TrimPrefix(e.URL, "ssh://"), e.SSHConfig.Username, e.SSHConfig.Password, e.ClientConfig)
+		result.Connected, cli, err = client.CanCreateSSHConnection(strings.TrimPrefix(e.URL, "ssh://"), e.SSHConfig.Username, e.SSHConfig.Password, e.SSHConfig.PrivateKey, e.ClientConfig)
 		if err != nil {
 			result.AddError(err.Error())
 			return

config/endpoint/endpoint_test.go

@@ -511,26 +511,40 @@ func TestEndpoint_ValidateAndSetDefaultsWithSSH(t *testing.T) {
 		name        string
 		username    string
 		password    string
+		privateKey  string
 		expectedErr error
 	}{
 		{
-			name:        "fail when has no user",
+			name:        "fail when has no user but has password",
 			username:    "",
 			password:    "password",
 			expectedErr: ssh.ErrEndpointWithoutSSHUsername,
 		},
 		{
-			name:        "fail when has no password",
-			username:    "username",
-			password:    "",
-			expectedErr: ssh.ErrEndpointWithoutSSHPassword,
+			name:        "fail when has no user but has private key",
+			username:    "",
+			privateKey:  "-----BEGIN",
+			expectedErr: ssh.ErrEndpointWithoutSSHUsername,
 		},
 		{
-			name:        "success when all fields are set",
+			name:        "fail when has no password or private key",
+			username:    "username",
+			password:    "",
+			privateKey:  "",
+			expectedErr: ssh.ErrEndpointWithoutSSHAuth,
+		},
+		{
+			name:        "success when username and password are set",
 			username:    "username",
 			password:    "password",
 			expectedErr: nil,
 		},
+		{
+			name:        "success when username and private key are set",
+			username:    "username",
+			privateKey:  "-----BEGIN",
+			expectedErr: nil,
+		},
 	}
 
 	for _, scenario := range scenarios {
@@ -539,8 +553,9 @@ func TestEndpoint_ValidateAndSetDefaultsWithSSH(t *testing.T) {
 				Name: "ssh-test",
 				URL:  "https://example.com",
 				SSHConfig: &ssh.Config{
-					Username: scenario.username,
-					Password: scenario.password,
+					Username:   scenario.username,
+					Password:   scenario.password,
+					PrivateKey: scenario.privateKey,
 				},
 				Conditions: []Condition{Condition("[STATUS] == 0")},
 			}
@@ -1605,7 +1620,7 @@ func TestEndpoint_HideUIFeatures(t *testing.T) {
 				}
 			}
 			if tt.checkConditions {
-				hasConditions := result.ConditionResults != nil && len(result.ConditionResults) > 0
+				hasConditions := len(result.ConditionResults) > 0
 				if hasConditions != tt.expectConditions {
 					t.Errorf("Expected conditions=%v, got conditions=%v (actual: %v)", tt.expectConditions, hasConditions, result.ConditionResults)
 				}

config/endpoint/ssh/ssh.go

@@ -8,26 +8,29 @@ var (
 	// ErrEndpointWithoutSSHUsername is the error with which Gatus will panic if an endpoint with SSH monitoring is configured without a user.
 	ErrEndpointWithoutSSHUsername = errors.New("you must specify a username for each SSH endpoint")
 
-	// ErrEndpointWithoutSSHPassword is the error with which Gatus will panic if an endpoint with SSH monitoring is configured without a password.
-	ErrEndpointWithoutSSHPassword = errors.New("you must specify a password for each SSH endpoint")
+	// ErrEndpointWithoutSSHAuth is the error with which Gatus will panic if an endpoint with SSH monitoring is configured without a password or private key.
+	ErrEndpointWithoutSSHAuth = errors.New("you must specify a password or private-key for each SSH endpoint")
 )
 
 type Config struct {
-	Username string `yaml:"username,omitempty"`
-	Password string `yaml:"password,omitempty"`
+	Username   string `yaml:"username,omitempty"`
+	Password   string `yaml:"password,omitempty"`
+	PrivateKey string `yaml:"private-key,omitempty"`
 }
 
 // Validate the SSH configuration
 func (cfg *Config) Validate() error {
-	// If there's no username and password, this endpoint can still check the SSH banner, so the endpoint is still valid
-	if len(cfg.Username) == 0 && len(cfg.Password) == 0 {
+	// If there's no username, password, or private key, this endpoint can still check the SSH banner, so the endpoint is still valid
+	if len(cfg.Username) == 0 && len(cfg.Password) == 0 && len(cfg.PrivateKey) == 0 {
 		return nil
 	}
+	// If any authentication method is provided (password or private key), a username is required
 	if len(cfg.Username) == 0 {
 		return ErrEndpointWithoutSSHUsername
 	}
-	if len(cfg.Password) == 0 {
-		return ErrEndpointWithoutSSHPassword
+	// If a username is provided, require at least a password or a private key
+	if len(cfg.Password) == 0 && len(cfg.PrivateKey) == 0 {
+		return ErrEndpointWithoutSSHAuth
 	}
 	return nil
 }

config/endpoint/ssh/ssh_test.go

@@ -5,7 +5,7 @@ import (
 	"testing"
 )
 
-func TestSSH_validate(t *testing.T) {
+func TestSSH_validatePasswordCfg(t *testing.T) {
 	cfg := &Config{}
 	if err := cfg.Validate(); err != nil {
 		t.Error("didn't expect an error")
@@ -13,11 +13,26 @@ func TestSSH_validate(t *testing.T) {
 	cfg.Username = "username"
 	if err := cfg.Validate(); err == nil {
 		t.Error("expected an error")
-	} else if !errors.Is(err, ErrEndpointWithoutSSHPassword) {
-		t.Errorf("expected error to be '%v', got '%v'", ErrEndpointWithoutSSHPassword, err)
+	} else if !errors.Is(err, ErrEndpointWithoutSSHAuth) {
+		t.Errorf("expected error to be '%v', got '%v'", ErrEndpointWithoutSSHAuth, err)
 	}
 	cfg.Password = "password"
 	if err := cfg.Validate(); err != nil {
 		t.Errorf("expected no error, got '%v'", err)
 	}
 }
+
+func TestSSH_validatePrivateKeyCfg(t *testing.T) {
+	t.Run("fail when username missing but private key provided", func(t *testing.T) {
+		cfg := &Config{PrivateKey: "-----BEGIN"}
+		if err := cfg.Validate(); !errors.Is(err, ErrEndpointWithoutSSHUsername) {
+			t.Fatalf("expected ErrEndpointWithoutSSHUsername, got %v", err)
+		}
+	})
+	t.Run("success when username with private key", func(t *testing.T) {
+		cfg := &Config{Username: "user", PrivateKey: "-----BEGIN"}
+		if err := cfg.Validate(); err != nil {
+			t.Fatalf("expected no error, got %v", err)
+		}
+	})
+}