feat: enable auth for local requests to Corrosion API (resolves #110)

internal/corrosion/client.go

@@ -33,21 +33,22 @@ type APIClient struct {
 	newResubBackoff func() backoff.BackOff
 }
 
-// NewAPIClient creates a new Corrosion API client. The client retries on network errors using an exponential backoff
-// policy with a maximum interval of 1 second and a maximum elapsed time of 10 seconds.
+// NewAPIClient creates a new Corrosion API client. The bearerToken is sent in the Authorization header of every
+// request to authenticate against Corrosion API.
+// The client retries on network errors using an exponential backoff policy with a maximum interval of 1 second and
+// a maximum elapsed time of 10 seconds.
 // It automatically resubscribes to active subscriptions if an error occurs using an exponential backoff policy with a
 // maximum interval of 1 second and a maximum elapsed time of 60 seconds.
 // Use the WithHTTP2Client option to provide a custom HTTP client and the WithResubscribeBackoff option to change the
 // backoff policy for resubscribing to a query.
-func NewAPIClient(addr netip.AddrPort, opts ...APIClientOption) (*APIClient, error) {
+func NewAPIClient(addr netip.AddrPort, bearerToken string, opts ...APIClientOption) (*APIClient, error) {
 	baseURL, err := url.Parse(fmt.Sprintf("http://%s", addr))
 	if err != nil {
 		return nil, fmt.Errorf("invalid URL: %w", err)
 	}
-	c := &APIClient{
-		baseURL: baseURL,
-		client: &http.Client{
-			Transport: &RetryRoundTripper{
+
+	transport := &AuthRoundTripper{
+		Base: &RetryRoundTripper{
 			Base: &http2.Transport{
 				AllowHTTP: true,
 				DialTLSContext: func(ctx context.Context, network, addr string, _ *tls.Config) (net.Conn, error) {
@@ -65,7 +66,11 @@ func NewAPIClient(addr netip.AddrPort, opts ...APIClientOption) (*APIClient, err
 				)
 			},
 		},
-		},
+		Token: bearerToken,
+	}
+	c := &APIClient{
+		baseURL: baseURL,
+		client:  &http.Client{Transport: transport},
 		newResubBackoff: func() backoff.BackOff {
 			return backoff.NewExponentialBackOff(
 				backoff.WithInitialInterval(100*time.Millisecond),
@@ -83,6 +88,8 @@ func NewAPIClient(addr netip.AddrPort, opts ...APIClientOption) (*APIClient, err
 
 type APIClientOption func(*APIClient)
 
+// WithHTTP2Client replaces the client's HTTP transport. The provided client bypasses the built-in bearer-token
+// injection, so the caller is responsible for setting the Authorization header.
 func WithHTTP2Client(client *http.Client) APIClientOption {
 	return func(c *APIClient) {
 		c.client = client
@@ -97,6 +104,22 @@ func WithResubscribeBackoff(newBackoff func() backoff.BackOff) APIClientOption {
 	}
 }
 
+// AuthRoundTripper sets the Authorization header on every outgoing request. An empty Token leaves the header untouched.
+type AuthRoundTripper struct {
+	Base  http.RoundTripper
+	Token string
+}
+
+func (rt *AuthRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
+	if rt.Token == "" {
+		return rt.Base.RoundTrip(req)
+	}
+	// RoundTripper contract: must not mutate the caller's request.
+	req = req.Clone(req.Context())
+	req.Header.Set("Authorization", "Bearer "+rt.Token)
+	return rt.Base.RoundTrip(req)
+}
+
 type RetryRoundTripper struct {
 	Base http.RoundTripper
 	// NewBackoff creates a new backoff policy for each request.
@@ -107,8 +130,7 @@ func (rt *RetryRoundTripper) RoundTrip(req *http.Request) (*http.Response, error
 	roundTrip := func() (*http.Response, error) {
 		resp, err := rt.Base.RoundTrip(req)
 		if err != nil {
-			var opErr *net.OpError
-			if errors.As(err, &opErr) {
+			if _, ok := errors.AsType[*net.OpError](err); ok {
 				// Not certain, but I expect operational errors should generally be retryable.
 				slog.Debug("Retrying corrosion API request due to network error.", "error", err)
 				return nil, err

internal/corrosion/client_test.go

@@ -0,0 +1,60 @@
+package corrosion
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestAuthRoundTripper_SetsAuthorizationHeader(t *testing.T) {
+	t.Parallel()
+
+	const token = "test-token-1234567890"
+
+	var gotAuth string
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		gotAuth = r.Header.Get("Authorization")
+		w.WriteHeader(http.StatusOK)
+	}))
+	defer srv.Close()
+
+	rt := &AuthRoundTripper{Base: http.DefaultTransport, Token: token}
+	client := &http.Client{Transport: rt}
+
+	req, err := http.NewRequest(http.MethodGet, srv.URL, nil)
+	require.NoError(t, err)
+
+	resp, err := client.Do(req)
+	require.NoError(t, err)
+	resp.Body.Close()
+
+	assert.Equal(t, "Bearer "+token, gotAuth)
+	// Caller's request must not be mutated by the RoundTripper.
+	assert.Empty(t, req.Header.Get("Authorization"))
+}
+
+func TestAuthRoundTripper_EmptyTokenSkipsHeader(t *testing.T) {
+	t.Parallel()
+
+	var headerSeen bool
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		_, headerSeen = r.Header["Authorization"]
+		w.WriteHeader(http.StatusOK)
+	}))
+	defer srv.Close()
+
+	rt := &AuthRoundTripper{Base: http.DefaultTransport, Token: ""}
+	client := &http.Client{Transport: rt}
+
+	req, err := http.NewRequest(http.MethodGet, srv.URL, nil)
+	require.NoError(t, err)
+
+	resp, err := client.Do(req)
+	require.NoError(t, err)
+	resp.Body.Close()
+
+	assert.False(t, headerSeen, "Authorization header should not be sent when token is empty")
+}

internal/machine/corroservice/config.go

@@ -38,6 +38,11 @@ type GossipConfig struct {
 
 type APIConfig struct {
 	Addr  netip.AddrPort `toml:"addr"`
+	Authz APIAuthzConfig `toml:"authz"`
+}
+
+type APIAuthzConfig struct {
+	BearerToken string `toml:"bearer-token"`
 }
 
 type AdminConfig struct {

internal/machine/corroservice/service.go

@@ -35,7 +35,7 @@ func WaitReady(ctx context.Context, dataDir string) error {
 		return fmt.Errorf("unmarshal config: %w", err)
 	}
 
-	corro, err := corrosion.NewAPIClient(config.API.Addr)
+	corro, err := corrosion.NewAPIClient(config.API.Addr, config.API.Authz.BearerToken)
 	if err != nil {
 		return fmt.Errorf("create corrosion API client: %w", err)
 	}

internal/machine/machine.go

@@ -35,6 +35,7 @@ import (
 	machinedocker "github.com/psviderski/uncloud/internal/machine/docker"
 	"github.com/psviderski/uncloud/internal/machine/network"
 	"github.com/psviderski/uncloud/internal/machine/store"
+	"github.com/psviderski/uncloud/internal/secret"
 	"github.com/psviderski/uncloud/pkg/api"
 	"github.com/psviderski/unregistry"
 	"github.com/siderolabs/grpc-proxy/proxy"
@@ -224,7 +225,21 @@ func NewMachine(config *Config) (*Machine, error) {
 		}
 	}
 
-	corro, err := corrosion.NewAPIClient(config.CorrosionAPIAddr)
+	// Generate and persist a token for Corrosion API if not already present in the state.
+	if len(state.CorrosionAPIToken) == 0 {
+		token, tErr := secret.New(16)
+		if tErr != nil {
+			return nil, fmt.Errorf("generate corrosion API token: %w", tErr)
+		}
+
+		state.CorrosionAPIToken = token
+		if err = state.Save(); err != nil {
+			return nil, fmt.Errorf("save machine state with corrosion API token: %w", err)
+		}
+		slog.Info("Generated Corrosion API bearer token.")
+	}
+
+	corro, err := corrosion.NewAPIClient(config.CorrosionAPIAddr, state.CorrosionAPIToken.String())
 	if err != nil {
 		return nil, fmt.Errorf("create corrosion API client: %w", err)
 	}
@@ -603,6 +618,9 @@ func listenUnixSocket(path string) (net.Listener, error) {
 }
 
 func (m *Machine) configureCorrosion() error {
+	if len(m.state.CorrosionAPIToken) == 0 {
+		return fmt.Errorf("corrosion API token not set in machine state")
+	}
 	if err := corroservice.MkDir(m.config.CorrosionDataDir, m.config.CorrosionUser); err != nil {
 		return fmt.Errorf("create corrosion data directory: %w", err)
 	}
@@ -639,6 +657,9 @@ func (m *Machine) configureCorrosion() error {
 		},
 		API: corroservice.APIConfig{
 			Addr: m.config.CorrosionAPIAddr,
+			Authz: corroservice.APIAuthzConfig{
+				BearerToken: m.state.CorrosionAPIToken.String(),
+			},
 		},
 		Admin: corroservice.AdminConfig{
 			Path: m.config.CorrosionAdminSockPath,

internal/machine/state.go

@@ -8,6 +8,7 @@ import (
 	"sync"
 
 	"github.com/psviderski/uncloud/internal/machine/network"
+	"github.com/psviderski/uncloud/internal/secret"
 )
 
 const (
@@ -28,6 +29,8 @@ type State struct {
 	// Per-actor vector (Corrosion actor UUID → max applied db_version) captured from an existing
 	// member at join time. Cleared once reached.
 	MinStoreVersion map[string]int64 `json:",omitempty"`
+	// CorrosionAPIToken authenticates requests to the local Corrosion API.
+	CorrosionAPIToken secret.Secret `json:",omitempty"`
 
 	// path is the file path config is read from and saved to.
 	path string