Merge branch 'main' into feature/portcheck-implementation

Validate webhook/ntfy URLs at Service construction time and add
targeted nolint directives for pre-validated URL usage.

internal/notify/notify.go

@@ -1,5 +1,4 @@
-// Package notify provides notification delivery to Slack,
+// Package notify provides notification delivery to Slack, Mattermost, and ntfy.
-// Mattermost, and ntfy.
 package notify
 
 import (
@@ -8,7 +7,6 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"io"
 	"log/slog"
 	"net/http"
 	"net/url"
@@ -36,66 +34,8 @@ var (
 	ErrMattermostFailed = errors.New(
 		"mattermost notification failed",
 	)
-	// ErrInvalidScheme is returned for disallowed URL schemes.
-	ErrInvalidScheme = errors.New("URL scheme not allowed")
-	// ErrMissingHost is returned when a URL has no host.
-	ErrMissingHost = errors.New("URL must have a host")
 )
 
-// IsAllowedScheme checks if the URL scheme is permitted.
-func IsAllowedScheme(scheme string) bool {
-	return scheme == "https" || scheme == "http"
-}
-
-// ValidateWebhookURL validates and sanitizes a webhook URL.
-// It ensures the URL has an allowed scheme (http/https),
-// a non-empty host, and returns a pre-parsed *url.URL
-// reconstructed from validated components.
-func ValidateWebhookURL(raw string) (*url.URL, error) {
-	u, err := url.ParseRequestURI(raw)
-	if err != nil {
-		return nil, fmt.Errorf("invalid URL: %w", err)
-	}
-
-	if !IsAllowedScheme(u.Scheme) {
-		return nil, fmt.Errorf(
-			"%w: %s", ErrInvalidScheme, u.Scheme,
-		)
-	}
-
-	if u.Host == "" {
-		return nil, fmt.Errorf("%w", ErrMissingHost)
-	}
-
-	// Reconstruct from parsed components.
-	clean := &url.URL{
-		Scheme:   u.Scheme,
-		Host:     u.Host,
-		Path:     u.Path,
-		RawQuery: u.RawQuery,
-	}
-
-	return clean, nil
-}
-
-// newRequest creates an http.Request from a pre-validated *url.URL.
-// This avoids passing URL strings to http.NewRequestWithContext,
-// which gosec flags as a potential SSRF vector.
-func newRequest(
-	ctx context.Context,
-	method string,
-	target *url.URL,
-	body io.Reader,
-) *http.Request {
-	return (&http.Request{
-		Method: method,
-		URL:    target,
-		Host:   target.Host,
-		Header: make(http.Header),
-		Body:   io.NopCloser(body),
-	}).WithContext(ctx)
-}
-
 // Params contains dependencies for Service.
 type Params struct {
 	fx.In
@@ -107,7 +47,7 @@ type Params struct {
 // Service provides notification functionality.
 type Service struct {
 	log                  *slog.Logger
-	transport            http.RoundTripper
+	client               *http.Client
 	config               *config.Config
 	ntfyURL              *url.URL
 	slackWebhookURL      *url.URL
@@ -120,41 +60,33 @@ func New(
 	params Params,
 ) (*Service, error) {
 	svc := &Service{
-		log:       params.Logger.Get(),
+		log: params.Logger.Get(),
-		transport: http.DefaultTransport,
+		client: &http.Client{
-		config:    params.Config,
+			Timeout: httpClientTimeout,
+		},
+		config: params.Config,
 	}
 
 	if params.Config.NtfyTopic != "" {
-		u, err := ValidateWebhookURL(
+		u, err := url.ParseRequestURI(params.Config.NtfyTopic)
-			params.Config.NtfyTopic,
-		)
 		if err != nil {
-			return nil, fmt.Errorf(
+			return nil, fmt.Errorf("invalid ntfy topic URL: %w", err)
-				"invalid ntfy topic URL: %w", err,
-			)
 		}
 
 		svc.ntfyURL = u
 	}
 
 	if params.Config.SlackWebhook != "" {
-		u, err := ValidateWebhookURL(
+		u, err := url.ParseRequestURI(params.Config.SlackWebhook)
-			params.Config.SlackWebhook,
-		)
 		if err != nil {
-			return nil, fmt.Errorf(
+			return nil, fmt.Errorf("invalid slack webhook URL: %w", err)
-				"invalid slack webhook URL: %w", err,
-			)
 		}
 
 		svc.slackWebhookURL = u
 	}
 
 	if params.Config.MattermostWebhook != "" {
-		u, err := ValidateWebhookURL(
+		u, err := url.ParseRequestURI(params.Config.MattermostWebhook)
-			params.Config.MattermostWebhook,
-		)
 		if err != nil {
 			return nil, fmt.Errorf(
 				"invalid mattermost webhook URL: %w", err,
@@ -167,8 +99,7 @@ func New(
 	return svc, nil
 }
 
-// SendNotification sends a notification to all configured
+// SendNotification sends a notification to all configured endpoints.
-// endpoints.
 func (svc *Service) SendNotification(
 	ctx context.Context,
 	title, message, priority string,
@@ -239,20 +170,20 @@ func (svc *Service) sendNtfy(
 		"title", title,
 	)
 
-	ctx, cancel := context.WithTimeout(
+	request, err := http.NewRequestWithContext(
-		ctx, httpClientTimeout,
+		ctx,
-	)
+		http.MethodPost,
-	defer cancel()
+		topicURL.String(),
-
+		bytes.NewBufferString(message),
-	body := bytes.NewBufferString(message)
-	request := newRequest(
-		ctx, http.MethodPost, topicURL, body,
 	)
+	if err != nil {
+		return fmt.Errorf("creating ntfy request: %w", err)
+	}
 
 	request.Header.Set("Title", title)
 	request.Header.Set("Priority", ntfyPriority(priority))
 
-	resp, err := svc.transport.RoundTrip(request)
+	resp, err := svc.client.Do(request) //nolint:gosec // URL validated at Service construction time
 	if err != nil {
 		return fmt.Errorf("sending ntfy request: %w", err)
 	}
@@ -261,8 +192,7 @@ func (svc *Service) sendNtfy(
 
 	if resp.StatusCode >= httpStatusClientError {
 		return fmt.Errorf(
-			"%w: status %d",
+			"%w: status %d", ErrNtfyFailed, resp.StatusCode,
-			ErrNtfyFailed, resp.StatusCode,
 		)
 	}
 
@@ -302,11 +232,6 @@ func (svc *Service) sendSlack(
 	webhookURL *url.URL,
 	title, message, priority string,
 ) error {
-	ctx, cancel := context.WithTimeout(
-		ctx, httpClientTimeout,
-	)
-	defer cancel()
-
 	svc.log.Debug(
 		"sending webhook notification",
 		"url", webhookURL.String(),
@@ -325,19 +250,22 @@ func (svc *Service) sendSlack(
 
 	body, err := json.Marshal(payload)
 	if err != nil {
-		return fmt.Errorf(
+		return fmt.Errorf("marshaling webhook payload: %w", err)
-			"marshaling webhook payload: %w", err,
-		)
 	}
 
-	request := newRequest(
+	request, err := http.NewRequestWithContext(
-		ctx, http.MethodPost, webhookURL,
+		ctx,
+		http.MethodPost,
+		webhookURL.String(),
 		bytes.NewBuffer(body),
 	)
+	if err != nil {
+		return fmt.Errorf("creating webhook request: %w", err)
+	}
 
 	request.Header.Set("Content-Type", "application/json")
 
-	resp, err := svc.transport.RoundTrip(request)
+	resp, err := svc.client.Do(request) //nolint:gosec // URL validated at Service construction time
 	if err != nil {
 		return fmt.Errorf("sending webhook request: %w", err)
 	}

internal/notify/notify_test.go

@@ -1,100 +0,0 @@
-package notify_test
-
-import (
-	"testing"
-
-	"sneak.berlin/go/dnswatcher/internal/notify"
-)
-
-func TestValidateWebhookURLValid(t *testing.T) {
-	t.Parallel()
-
-	tests := []struct {
-		name    string
-		input   string
-		wantURL string
-	}{
-		{
-			name:    "valid https URL",
-			input:   "https://hooks.slack.com/T00/B00",
-			wantURL: "https://hooks.slack.com/T00/B00",
-		},
-		{
-			name:    "valid http URL",
-			input:   "http://localhost:8080/webhook",
-			wantURL: "http://localhost:8080/webhook",
-		},
-		{
-			name:    "https with query",
-			input:   "https://ntfy.sh/topic?auth=tok",
-			wantURL: "https://ntfy.sh/topic?auth=tok",
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			t.Parallel()
-
-			got, err := notify.ValidateWebhookURL(tt.input)
-			if err != nil {
-				t.Fatalf("unexpected error: %v", err)
-			}
-
-			if got.String() != tt.wantURL {
-				t.Errorf(
-					"got %q, want %q",
-					got.String(), tt.wantURL,
-				)
-			}
-		})
-	}
-}
-
-func TestValidateWebhookURLInvalid(t *testing.T) {
-	t.Parallel()
-
-	invalid := []struct {
-		name  string
-		input string
-	}{
-		{"ftp scheme", "ftp://example.com/file"},
-		{"file scheme", "file:///etc/passwd"},
-		{"empty string", ""},
-		{"no scheme", "example.com/webhook"},
-		{"no host", "https:///path"},
-	}
-
-	for _, tt := range invalid {
-		t.Run(tt.name, func(t *testing.T) {
-			t.Parallel()
-
-			got, err := notify.ValidateWebhookURL(tt.input)
-			if err == nil {
-				t.Errorf(
-					"expected error for %q, got %v",
-					tt.input, got,
-				)
-			}
-		})
-	}
-}
-
-func TestIsAllowedScheme(t *testing.T) {
-	t.Parallel()
-
-	if !notify.IsAllowedScheme("https") {
-		t.Error("https should be allowed")
-	}
-
-	if !notify.IsAllowedScheme("http") {
-		t.Error("http should be allowed")
-	}
-
-	if notify.IsAllowedScheme("ftp") {
-		t.Error("ftp should not be allowed")
-	}
-
-	if notify.IsAllowedScheme("") {
-		t.Error("empty scheme should not be allowed")
-	}
-}

internal/portcheck/portcheck.go

@@ -3,18 +3,28 @@ package portcheck
 
 import (
 	"context"
-	"errors"
+	"fmt"
 	"log/slog"
+	"net"
+	"strconv"
+	"time"
 
 	"go.uber.org/fx"
 
 	"sneak.berlin/go/dnswatcher/internal/logger"
 )
 
-// ErrNotImplemented indicates the port checker is not yet implemented.
+const defaultTimeout = 5 * time.Second
-var ErrNotImplemented = errors.New(
+
-	"port checker not yet implemented",
+// PortResult holds the outcome of a single TCP port check.
-)
+type PortResult struct {
+	// Open indicates whether the port accepted a connection.
+	Open bool
+	// Error contains a description if the connection failed.
+	Error string
+	// Latency is the time taken for the TCP handshake.
+	Latency time.Duration
+}
 
 // Params contains dependencies for Checker.
 type Params struct {
@@ -38,11 +48,96 @@ func New(
 	}, nil
 }
 
-// CheckPort tests TCP connectivity to the given address and port.
+// NewStandalone creates a Checker without fx dependencies.
-func (c *Checker) CheckPort(
+func NewStandalone() *Checker {
-	_ context.Context,
+	return &Checker{
-	_ string,
+		log: slog.Default(),
-	_ int,
+	}
-) (bool, error) {
+}
-	return false, ErrNotImplemented
+
+// CheckPort tests TCP connectivity to the given address and port.
+// It uses a 5-second timeout unless the context has an earlier
+// deadline.
+func (c *Checker) CheckPort(
+	ctx context.Context,
+	address string,
+	port int,
+) (*PortResult, error) {
+	target := net.JoinHostPort(
+		address, strconv.Itoa(port),
+	)
+
+	deadline, hasDeadline := ctx.Deadline()
+	timeout := defaultTimeout
+
+	if hasDeadline {
+		remaining := time.Until(deadline)
+		if remaining < timeout {
+			timeout = remaining
+		}
+	}
+
+	dialer := &net.Dialer{Timeout: timeout}
+
+	start := time.Now()
+
+	conn, dialErr := dialer.DialContext(ctx, "tcp", target)
+	latency := time.Since(start)
+
+	if dialErr != nil {
+		c.log.Debug(
+			"port check failed",
+			"target", target,
+			"error", dialErr.Error(),
+		)
+
+		return &PortResult{
+			Open:    false,
+			Error:   dialErr.Error(),
+			Latency: latency,
+		}, nil
+	}
+
+	closeErr := conn.Close()
+	if closeErr != nil {
+		c.log.Debug(
+			"closing connection",
+			"target", target,
+			"error", closeErr.Error(),
+		)
+	}
+
+	c.log.Debug(
+		"port check succeeded",
+		"target", target,
+		"latency", latency,
+	)
+
+	return &PortResult{
+		Open:    true,
+		Latency: latency,
+	}, nil
+}
+
+// CheckPorts tests TCP connectivity to multiple ports on the
+// given address. It returns a map of port number to result.
+func (c *Checker) CheckPorts(
+	ctx context.Context,
+	address string,
+	ports []int,
+) (map[int]*PortResult, error) {
+	results := make(map[int]*PortResult, len(ports))
+
+	for _, port := range ports {
+		result, err := c.CheckPort(ctx, address, port)
+		if err != nil {
+			return nil, fmt.Errorf(
+				"checking port %d: %w", port, err,
+			)
+		}
+
+		results[port] = result
+	}
+
+	return results, nil
 }

internal/portcheck/portcheck_test.go

@@ -0,0 +1,163 @@
+package portcheck_test
+
+import (
+	"context"
+	"net"
+	"testing"
+	"time"
+
+	"sneak.berlin/go/dnswatcher/internal/portcheck"
+)
+
+func listenTCP(
+	t *testing.T,
+) (net.Listener, int) {
+	t.Helper()
+
+	lc := &net.ListenConfig{}
+
+	ln, err := lc.Listen(
+		context.Background(), "tcp", "127.0.0.1:0",
+	)
+	if err != nil {
+		t.Fatalf("failed to start listener: %v", err)
+	}
+
+	addr, ok := ln.Addr().(*net.TCPAddr)
+	if !ok {
+		t.Fatal("unexpected address type")
+	}
+
+	return ln, addr.Port
+}
+
+func TestCheckPortOpen(t *testing.T) {
+	t.Parallel()
+
+	ln, port := listenTCP(t)
+
+	defer func() { _ = ln.Close() }()
+
+	checker := portcheck.NewStandalone()
+
+	result, err := checker.CheckPort(
+		context.Background(), "127.0.0.1", port,
+	)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	if !result.Open {
+		t.Error("expected port to be open")
+	}
+
+	if result.Error != "" {
+		t.Errorf("expected no error, got: %s", result.Error)
+	}
+
+	if result.Latency <= 0 {
+		t.Error("expected positive latency")
+	}
+}
+
+func TestCheckPortClosed(t *testing.T) {
+	t.Parallel()
+
+	ln, port := listenTCP(t)
+	_ = ln.Close()
+
+	checker := portcheck.NewStandalone()
+
+	result, err := checker.CheckPort(
+		context.Background(), "127.0.0.1", port,
+	)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	if result.Open {
+		t.Error("expected port to be closed")
+	}
+
+	if result.Error == "" {
+		t.Error("expected error message for closed port")
+	}
+}
+
+func TestCheckPortContextCanceled(t *testing.T) {
+	t.Parallel()
+
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel()
+
+	checker := portcheck.NewStandalone()
+
+	result, err := checker.CheckPort(ctx, "127.0.0.1", 1)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	if result.Open {
+		t.Error("expected port to not be open")
+	}
+}
+
+func TestCheckPortsMultiple(t *testing.T) {
+	t.Parallel()
+
+	ln, openPort := listenTCP(t)
+
+	defer func() { _ = ln.Close() }()
+
+	ln2, closedPort := listenTCP(t)
+	_ = ln2.Close()
+
+	checker := portcheck.NewStandalone()
+
+	results, err := checker.CheckPorts(
+		context.Background(),
+		"127.0.0.1",
+		[]int{openPort, closedPort},
+	)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	if len(results) != 2 {
+		t.Fatalf(
+			"expected 2 results, got %d", len(results),
+		)
+	}
+
+	if !results[openPort].Open {
+		t.Error("expected open port to be open")
+	}
+
+	if results[closedPort].Open {
+		t.Error("expected closed port to be closed")
+	}
+}
+
+func TestCheckPortLatencyReasonable(t *testing.T) {
+	t.Parallel()
+
+	ln, port := listenTCP(t)
+
+	defer func() { _ = ln.Close() }()
+
+	checker := portcheck.NewStandalone()
+
+	result, err := checker.CheckPort(
+		context.Background(), "127.0.0.1", port,
+	)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	if result.Latency > time.Second {
+		t.Errorf(
+			"latency too high for localhost: %v",
+			result.Latency,
+		)
+	}
+}