feat: Add Cloudflare Tunnel support (ported from Castle)

Port Castle's tunnel config generator to Go. Central can now manage
cloudflared ingress configuration for public service exposure.

Services with reach=public get projected at <subdomain>.<publicDomain>
with Host/SNI rewriting to the internal domain so the gateway's wildcard
cert validates and existing routing works unchanged.

- Locally-managed config.yml (not remotely-managed token tunnel)
- Public surface is exactly the set of reach=public services
- Auto-removes config when tunnel is disabled or no public services
- 7 tests covering basic generation, subdomain override, edge cases

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
This commit is contained in:
2026-07-08 23:41:00 +00:00
parent c47689c3f2
commit a3b3339254
2 changed files with 353 additions and 0 deletions

196
internal/tunnel/manager.go Normal file
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// Package tunnel manages Cloudflare Tunnel (cloudflared) configuration.
//
// Services with reach=public are projected onto the internet at
// <subdomain>.<publicDomain>. The tunnel bridges each public hostname
// to Central's gateway via Host/SNI rewriting, so the gateway's wildcard
// cert validates and existing routing works unchanged.
//
// The config is locally-managed (a config.yml with an explicit ingress
// list), not a remotely-managed token tunnel — the public surface is
// exactly the set of registered public services.
package tunnel
import (
"fmt"
"log/slog"
"os"
"os/exec"
"path/filepath"
"strings"
"gopkg.in/yaml.v3"
)
// Config holds tunnel configuration.
type Config struct {
Enabled bool `yaml:"enabled" json:"enabled"`
TunnelID string `yaml:"tunnelId" json:"tunnelId"`
PublicDomain string `yaml:"publicDomain" json:"publicDomain"` // e.g. "pub.payne.io"
GatewayDomain string `yaml:"gatewayDomain" json:"gatewayDomain"` // e.g. "payne.io" (internal)
CredentialsDir string `yaml:"credentialsDir" json:"credentialsDir"`
}
// PublicService describes a service that should be exposed through the tunnel.
type PublicService struct {
Name string // service name (used as subdomain)
Subdomain string // explicit subdomain override (defaults to Name)
}
// Manager handles cloudflared tunnel configuration.
type Manager struct {
dataDir string
}
// NewManager creates a new tunnel manager.
func NewManager(dataDir string) *Manager {
return &Manager{dataDir: dataDir}
}
// configPath returns the path to the generated cloudflared config.
func (m *Manager) configPath() string {
return filepath.Join(m.dataDir, "tunnel", "config.yml")
}
// credentialsPath returns the path to the tunnel credentials JSON.
func credentialsPath(credentialsDir, tunnelID string) string {
if credentialsDir == "" {
credentialsDir = filepath.Join(os.Getenv("HOME"), ".cloudflared")
}
return filepath.Join(credentialsDir, tunnelID+".json")
}
// ingressEntry is a single cloudflared ingress rule.
type ingressEntry struct {
Hostname string `yaml:"hostname,omitempty"`
Service string `yaml:"service"`
OriginRequest *originRequestConfig `yaml:"originRequest,omitempty"`
}
type originRequestConfig struct {
OriginServerName string `yaml:"originServerName,omitempty"`
HTTPHostHeader string `yaml:"httpHostHeader,omitempty"`
}
type cloudflaredConfig struct {
Tunnel string `yaml:"tunnel"`
CredentialsFile string `yaml:"credentials-file"`
Ingress []ingressEntry `yaml:"ingress"`
}
// GenerateConfig renders the cloudflared config.yml for the given public services.
// Returns the YAML string, or empty string if tunnel is not configured or no services are public.
func (m *Manager) GenerateConfig(cfg Config, services []PublicService) string {
if !cfg.Enabled || cfg.TunnelID == "" || cfg.PublicDomain == "" || cfg.GatewayDomain == "" {
return ""
}
if len(services) == 0 {
return ""
}
// The gateway origin — HAProxy terminates TLS on 443, so we connect there.
gatewayOrigin := "https://localhost:443"
var ingress []ingressEntry
for _, svc := range services {
subdomain := svc.Subdomain
if subdomain == "" {
subdomain = svc.Name
}
publicHost := subdomain + "." + cfg.PublicDomain
internalHost := subdomain + "." + cfg.GatewayDomain
ingress = append(ingress, ingressEntry{
Hostname: publicHost,
Service: gatewayOrigin,
OriginRequest: &originRequestConfig{
OriginServerName: internalHost,
HTTPHostHeader: internalHost,
},
})
}
// Cloudflared requires a terminal catch-all
ingress = append(ingress, ingressEntry{
Service: "http_status:404",
})
config := cloudflaredConfig{
Tunnel: cfg.TunnelID,
CredentialsFile: credentialsPath(cfg.CredentialsDir, cfg.TunnelID),
Ingress: ingress,
}
data, err := yaml.Marshal(config)
if err != nil {
slog.Error("failed to marshal tunnel config", "error", err)
return ""
}
return string(data)
}
// WriteConfig generates and writes the cloudflared config to disk.
func (m *Manager) WriteConfig(cfg Config, services []PublicService) error {
content := m.GenerateConfig(cfg, services)
if content == "" {
// Remove config if tunnel is disabled or no public services
path := m.configPath()
if _, err := os.Stat(path); err == nil {
os.Remove(path)
slog.Info("tunnel config removed (no public services)")
}
return nil
}
dir := filepath.Dir(m.configPath())
if err := os.MkdirAll(dir, 0755); err != nil {
return fmt.Errorf("creating tunnel config dir: %w", err)
}
if err := os.WriteFile(m.configPath(), []byte(content), 0644); err != nil {
return fmt.Errorf("writing tunnel config: %w", err)
}
slog.Info("tunnel config written", "path", m.configPath(), "services", len(services))
return nil
}
// GetStatus returns the current tunnel status.
func (m *Manager) GetStatus(cfg Config) map[string]any {
status := map[string]any{
"enabled": cfg.Enabled,
"tunnelId": cfg.TunnelID,
"publicDomain": cfg.PublicDomain,
"configPath": m.configPath(),
}
// Check if cloudflared is running
cmd := exec.Command("systemctl", "is-active", "cloudflared.service")
output, err := cmd.Output()
if err != nil {
status["service"] = "inactive"
} else {
status["service"] = strings.TrimSpace(string(output))
}
// Check if config exists
if _, err := os.Stat(m.configPath()); err == nil {
status["configExists"] = true
} else {
status["configExists"] = false
}
return status
}
// ReloadService restarts the cloudflared service to pick up new config.
func (m *Manager) ReloadService() error {
cmd := exec.Command("systemctl", "restart", "cloudflared.service")
output, err := cmd.CombinedOutput()
if err != nil {
return fmt.Errorf("failed to restart cloudflared: %w (output: %s)", err, string(output))
}
slog.Info("cloudflared service restarted")
return nil
}

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package tunnel
import (
"os"
"path/filepath"
"strings"
"testing"
)
func testConfig() Config {
return Config{
Enabled: true,
TunnelID: "abc-123",
PublicDomain: "pub.payne.io",
GatewayDomain: "payne.io",
CredentialsDir: "/tmp/creds",
}
}
func TestGenerateConfig_Basic(t *testing.T) {
m := NewManager(t.TempDir())
services := []PublicService{
{Name: "my-api"},
{Name: "dashboard"},
}
out := m.GenerateConfig(testConfig(), services)
if out == "" {
t.Fatal("expected non-empty config")
}
// Check tunnel ID
if !strings.Contains(out, "tunnel: abc-123") {
t.Errorf("expected tunnel ID, got:\n%s", out)
}
// Check credentials file
if !strings.Contains(out, "credentials-file: /tmp/creds/abc-123.json") {
t.Errorf("expected credentials file, got:\n%s", out)
}
// Check public hostnames
if !strings.Contains(out, "hostname: my-api.pub.payne.io") {
t.Errorf("expected my-api public hostname, got:\n%s", out)
}
if !strings.Contains(out, "hostname: dashboard.pub.payne.io") {
t.Errorf("expected dashboard public hostname, got:\n%s", out)
}
// Check Host/SNI rewriting to internal domain
if !strings.Contains(out, "originServerName: my-api.payne.io") {
t.Errorf("expected internal SNI for my-api, got:\n%s", out)
}
if !strings.Contains(out, "httpHostHeader: dashboard.payne.io") {
t.Errorf("expected internal Host header for dashboard, got:\n%s", out)
}
// Check catch-all
if !strings.Contains(out, "service: http_status:404") {
t.Errorf("expected catch-all 404, got:\n%s", out)
}
// Check gateway origin
if !strings.Contains(out, "service: https://localhost:443") {
t.Errorf("expected gateway origin, got:\n%s", out)
}
}
func TestGenerateConfig_SubdomainOverride(t *testing.T) {
m := NewManager(t.TempDir())
services := []PublicService{
{Name: "internal-name", Subdomain: "public-name"},
}
out := m.GenerateConfig(testConfig(), services)
if !strings.Contains(out, "hostname: public-name.pub.payne.io") {
t.Errorf("expected subdomain override, got:\n%s", out)
}
}
func TestGenerateConfig_Disabled(t *testing.T) {
m := NewManager(t.TempDir())
cfg := testConfig()
cfg.Enabled = false
out := m.GenerateConfig(cfg, []PublicService{{Name: "my-api"}})
if out != "" {
t.Errorf("expected empty config when disabled, got:\n%s", out)
}
}
func TestGenerateConfig_NoServices(t *testing.T) {
m := NewManager(t.TempDir())
out := m.GenerateConfig(testConfig(), nil)
if out != "" {
t.Errorf("expected empty config with no services, got:\n%s", out)
}
}
func TestGenerateConfig_MissingTunnelID(t *testing.T) {
m := NewManager(t.TempDir())
cfg := testConfig()
cfg.TunnelID = ""
out := m.GenerateConfig(cfg, []PublicService{{Name: "my-api"}})
if out != "" {
t.Errorf("expected empty config with missing tunnel ID, got:\n%s", out)
}
}
func TestWriteConfig(t *testing.T) {
tmpDir := t.TempDir()
m := NewManager(tmpDir)
services := []PublicService{{Name: "my-api"}}
if err := m.WriteConfig(testConfig(), services); err != nil {
t.Fatalf("WriteConfig failed: %v", err)
}
// Verify file was written
configPath := filepath.Join(tmpDir, "tunnel", "config.yml")
data, err := os.ReadFile(configPath)
if err != nil {
t.Fatalf("Failed to read config: %v", err)
}
if !strings.Contains(string(data), "my-api.pub.payne.io") {
t.Errorf("expected my-api hostname in written config, got:\n%s", string(data))
}
}
func TestWriteConfig_RemovesWhenDisabled(t *testing.T) {
tmpDir := t.TempDir()
m := NewManager(tmpDir)
// Write config first
if err := m.WriteConfig(testConfig(), []PublicService{{Name: "my-api"}}); err != nil {
t.Fatalf("WriteConfig failed: %v", err)
}
// Now disable and write again — should remove the file
cfg := testConfig()
cfg.Enabled = false
if err := m.WriteConfig(cfg, []PublicService{{Name: "my-api"}}); err != nil {
t.Fatalf("WriteConfig (disable) failed: %v", err)
}
configPath := filepath.Join(tmpDir, "tunnel", "config.yml")
if _, err := os.Stat(configPath); !os.IsNotExist(err) {
t.Error("expected config file to be removed when disabled")
}
}