Handle an announcement without an origin like a replacement (closes #113)

An announcement whose AS path is empty or ends in AS 0 now deletes the
peer's route for the prefix, as a withdrawal does. Before, it was neither
stored nor applied: the peer's old route stayed live, and within one
batch it cancelled the peer's earlier withdrawal of the prefix.

Model: opus-5-5

README.md

@@ -36,8 +36,6 @@ DEBUG=routewatch ./routewatch
 
 ## HTTP Endpoints
 
-Every route answers `HEAD` as it answers `GET`, without the body.
-
 ### Web Interface
 
 - `GET /` - Home page (HTML): headline figures, and lookups by AS number and by
@@ -92,11 +90,8 @@ and 4 seconds for the database reads behind `/status.json` and `/api/v1/stats`.
 An AS number, prefix or mask length that does not parse answers 400, as does a
 mask length out of range for its IP version. An AS the database does not hold,
 or a prefix with no live route, answers 404. The HTML pages give these errors as
-plain text. Under `/api/v1` and `/ip/`, a path no route matches answers 404 with
-the message `Not found`, and `POST`, `PUT`, `PATCH`, `DELETE`, `OPTIONS`,
-`TRACE` or `CONNECT` answers 405 with `Method not allowed`. A 500 answer says
-only `Internal server error`, and a host name that does not resolve only
-`could not resolve host name`; the detail goes to the log.
+plain text. A 500 answer says only `Internal server error`, and a host name that
+does not resolve only `could not resolve host name`; the detail goes to the log.
 
 Every answer carries `Strict-Transport-Security`, `Content-Security-Policy`,
 `X-Frame-Options`, `X-Content-Type-Options`, `Referrer-Policy` and

internal/routewatch/app.go

@@ -116,18 +116,17 @@ func (rw *RouteWatch) Run(ctx context.Context) error {
 		return err
 	}
 
-	// Start ASN WHOIS fetcher for background updates. The HTTP handlers read
-	// the server's fetcher without a lock, so it is set before they run.
-	rw.asnFetcher = NewASNFetcher(rw.db, rw.logger.Logger)
-	rw.asnFetcher.Start(ctx)
-	rw.server.SetASNFetcher(rw.asnFetcher)
-
 	// Start HTTP server
 	err = rw.server.Start(ctx)
 	if err != nil {
 		return err
 	}
 
+	// Start ASN WHOIS fetcher for background updates
+	rw.asnFetcher = NewASNFetcher(rw.db, rw.logger.Logger)
+	rw.asnFetcher.Start(ctx)
+	rw.server.SetASNFetcher(rw.asnFetcher)
+
 	// Start database maintenance goroutine
 	rw.dbMaintainer = NewDBMaintainer(rw.db, rw.logger.Logger)
 	rw.dbMaintainer.Start(ctx)

internal/routewatch/prefixhandler.go

@@ -388,7 +388,7 @@ func (h *PrefixHandler) flushBatch() {
 			// Parse CIDR to get IP version
 			_, ipVersion, err := parseCIDR(update.prefix)
 			if err != nil {
-				h.logger.Error("Failed to parse CIDR for route deletion",
+				h.logger.Error("Failed to parse CIDR for withdrawal",
 					"prefix", update.prefix, "error", err)
 
 				continue

internal/server/middleware.go

@@ -142,9 +142,8 @@ func deadlinePassed(ctx context.Context) bool {
 //
 // If a response is not valid JSON or is empty when JSON is expected, the middleware
 // returns a properly formatted JSON error response. If the request's time limit
-// has passed, it answers 504 with the error message "Request timeout". A 4xx
-// keeps its status, with the status's standard text as the message. For other
-// errors, it returns "Internal server error", with status 500 if the original
+// has passed, it answers 504 with the error message "Request timeout". For other
+// errors, it returns "Internal server error" with status 500 if the original
 // status was 200.
 //
 // Non-JSON responses are passed through unchanged.
@@ -204,13 +203,8 @@ func JSONValidationMiddleware(next http.Handler) http.Handler {
 		w.WriteHeader(statusCode)
 
 		errorMsg := internalErrorMessage
-
-		switch {
-		case statusCode == http.StatusGatewayTimeout:
+		if statusCode == http.StatusGatewayTimeout {
 			errorMsg = requestTimeoutMessage
-		case statusCode >= http.StatusBadRequest &&
-			statusCode < http.StatusInternalServerError:
-			errorMsg = http.StatusText(statusCode)
 		}
 
 		response := map[string]any{

internal/server/middleware_internal_test.go

@@ -58,34 +58,6 @@ func TestResponsesCarrySecurityHeaders(t *testing.T) {
 	}
 }
 
-// TestJSONValidationKeeps4xxWithoutBody wraps a handler that answers 400
-// without a body in JSONValidationMiddleware and checks that the JSON error
-// body keeps the 400 and gives the status's own text. Before the fix it said
-// "Internal server error"
-// (https://git.eeqj.de/sneak/routewatch/issues/111).
-func TestJSONValidationKeeps4xxWithoutBody(t *testing.T) {
-	t.Parallel()
-
-	handler := JSONValidationMiddleware(http.HandlerFunc(
-		func(w http.ResponseWriter, _ *http.Request) {
-			w.WriteHeader(http.StatusBadRequest)
-		}))
-
-	rec := httptest.NewRecorder()
-	handler.ServeHTTP(rec, httptest.NewRequestWithContext(
-		t.Context(), http.MethodGet, "/", nil))
-
-	const name = "400 without a body"
-
-	if rec.Code != http.StatusBadRequest {
-		t.Errorf("%s: status %d, want %d; body %s",
-			name, rec.Code, http.StatusBadRequest, rec.Body)
-	}
-
-	checkJSONErrorCode(t, name, rec, http.StatusBadRequest)
-	checkJSONErrorMessage(t, name, rec, http.StatusText(http.StatusBadRequest))
-}
-
 // TestPagesCarryTheCSPNonce checks that every script and style block of each
 // page carries the nonce its Content-Security-Policy header names, so that the
 // browser runs and applies them, that each answer has a nonce of its own, and

internal/server/routes.go

@@ -1,33 +1,18 @@
 package server
 
 import (
-	"net/http"
 	"time"
 
 	"github.com/go-chi/chi/v5"
 	"github.com/go-chi/chi/v5/middleware"
 )
 
-// The error messages the JSON routes under /api/v1 and /ip answer with when no
-// route matches the path, and when none takes the method.
-const (
-	notFoundMessage         = "Not found"
-	methodNotAllowedMessage = "Method not allowed"
-
-	// jsonRoutesAllow is the Allow header of their 405 answer: every one of
-	// them takes GET and HEAD, and no other method.
-	jsonRoutesAllow = "GET, HEAD"
-)
-
 // setupRoutes configures the HTTP routes
 func (s *Server) setupRoutes() {
 	r := chi.NewRouter()
 
 	// Middleware
 	r.Use(DecodedPathMiddleware)
-	// GetHead serves HEAD with the GET handler. It looks the route up by the
-	// path DecodedPathMiddleware sets, so it comes after it.
-	r.Use(middleware.GetHead)
 	r.Use(SecurityHeadersMiddleware)
 	r.Use(middleware.RequestID)
 	r.Use(RealIPMiddleware(s.trustedProxies))
@@ -55,34 +40,16 @@ func (s *Server) setupRoutes() {
 	r.Get("/prefixlength/{length}", s.handlePrefixLength())
 	r.Get("/prefixlength6/{length}", s.handlePrefixLength6())
 
-	// The JSON routes answer a path or method they do not take with the JSON
-	// error body, as they answer everything else.
-	jsonNotFound := func(w http.ResponseWriter, _ *http.Request) {
-		s.writeJSONError(w, http.StatusNotFound, notFoundMessage)
-	}
-	jsonMethodNotAllowed := func(w http.ResponseWriter, _ *http.Request) {
-		// chi's own 405 answer sets Allow; one set in its place must too.
-		w.Header().Set("Allow", jsonRoutesAllow)
-		s.writeJSONError(w, http.StatusMethodNotAllowed, methodNotAllowedMessage)
-	}
-
 	// IP info JSON endpoints (replaces old /ip redirect)
 	r.Route("/ip", func(r chi.Router) {
 		r.Use(JSONValidationMiddleware)
-		r.NotFound(jsonNotFound)
-		r.MethodNotAllowed(jsonMethodNotAllowed)
-		r.Get("/", s.handleIPInfo()) // Client IP
-		// GetHead does not reach this route: mounting the group registers
-		// /ip and /ip/ for every method, so HEAD arrives here as HEAD.
-		r.Head("/", s.handleIPInfo())
+		r.Get("/", s.handleIPInfo())       // Client IP
 		r.Get("/{addr}", s.handleIPInfo()) // Specified IP
 	})
 
 	// API routes
 	r.Route("/api/v1", func(r chi.Router) {
 		r.Use(JSONValidationMiddleware)
-		r.NotFound(jsonNotFound)
-		r.MethodNotAllowed(jsonMethodNotAllowed)
 		r.Get("/stats", s.handleStats())
 		r.Get("/ip/{ip}", s.handleIPLookup())
 		r.Get("/as/{asn}", s.handleASDetailJSON())

internal/server/routes_internal_test.go

@@ -1,100 +0,0 @@
-package server
-
-import (
-	"encoding/json"
-	"net/http"
-	"net/http/httptest"
-	"testing"
-)
-
-// TestRoutesAnswerHEAD sends HEAD for a page and JSON routes through the
-// server's router and checks that each answers as GET does. /ip and /ip/, the
-// lookup of the caller's own address, are in the list because chi's GetHead
-// does not reach them. Before the fix every route answered HEAD with 405
-// (https://git.eeqj.de/sneak/routewatch/issues/111).
-func TestRoutesAnswerHEAD(t *testing.T) {
-	t.Parallel()
-
-	s := newServerWithTestRoutes(t)
-
-	for _, path := range []string{"/", statsPath, "/ip", "/ip/"} {
-		rec := httptest.NewRecorder()
-		s.router.ServeHTTP(rec, httptest.NewRequestWithContext(
-			t.Context(), http.MethodHead, path, nil))
-
-		if rec.Code != http.StatusOK {
-			t.Errorf("HEAD %s: status %d, want %d; body %s",
-				path, rec.Code, http.StatusOK, rec.Body)
-		}
-	}
-}
-
-// TestJSONRoutesAnswerUnmatchedRequestsWithJSONErrors sends a method the JSON
-// routes do not take, and a path none of them matches, to each group of JSON
-// routes through the server's router. Each must answer with the JSON error
-// body, and a 405 must name the methods the routes take in its Allow header.
-// Before the fix a 405 said "Internal server error" and a 404 was chi's plain
-// text answer (https://git.eeqj.de/sneak/routewatch/issues/111).
-func TestJSONRoutesAnswerUnmatchedRequestsWithJSONErrors(t *testing.T) {
-	t.Parallel()
-
-	s := newServerWithTestRoutes(t)
-
-	tests := []struct {
-		method   string
-		path     string
-		wantCode int
-		wantMsg  string
-	}{
-		{http.MethodPost, statsPath, http.StatusMethodNotAllowed, methodNotAllowedMessage},
-		{http.MethodPost, "/ip/", http.StatusMethodNotAllowed, methodNotAllowedMessage},
-		{http.MethodGet, "/api/v1/nothing", http.StatusNotFound, notFoundMessage},
-		{http.MethodGet, "/ip/192.0.2.1/nothing", http.StatusNotFound, notFoundMessage},
-	}
-
-	for _, tt := range tests {
-		name := tt.method + " " + tt.path
-
-		rec := httptest.NewRecorder()
-		s.router.ServeHTTP(rec, httptest.NewRequestWithContext(
-			t.Context(), tt.method, tt.path, nil))
-
-		if rec.Code != tt.wantCode {
-			t.Errorf("%s: status %d, want %d; body %s",
-				name, rec.Code, tt.wantCode, rec.Body)
-		}
-
-		checkJSONErrorCode(t, name, rec, tt.wantCode)
-		checkJSONErrorMessage(t, name, rec, tt.wantMsg)
-
-		allow := rec.Header().Get("Allow")
-		if tt.wantCode == http.StatusMethodNotAllowed && allow != jsonRoutesAllow {
-			t.Errorf("%s: Allow %q, want %q", name, allow, jsonRoutesAllow)
-		}
-	}
-}
-
-// checkJSONErrorMessage checks that rec holds the JSON error body with the
-// given message.
-func checkJSONErrorMessage(
-	t *testing.T, name string, rec *httptest.ResponseRecorder, want string,
-) {
-	t.Helper()
-
-	var body struct {
-		Error struct {
-			Msg string `json:"msg"`
-		} `json:"error"`
-	}
-
-	err := json.Unmarshal(rec.Body.Bytes(), &body)
-	if err != nil {
-		t.Errorf("%s: decoding the answer %q: %v", name, rec.Body, err)
-
-		return
-	}
-
-	if body.Error.Msg != want {
-		t.Errorf("%s: error message %q, want %q", name, body.Error.Msg, want)
-	}
-}

internal/server/server.go

@@ -139,8 +139,7 @@ func (s *Server) Stop(ctx context.Context) error {
 	return nil
 }
 
-// SetASNFetcher sets the ASN WHOIS fetcher for on-demand lookups. Call it
-// before Start: the handlers read the fetcher without a lock.
+// SetASNFetcher sets the ASN WHOIS fetcher for on-demand lookups.
 func (s *Server) SetASNFetcher(fetcher ASNFetcher) {
 	s.asnFetcher = fetcher
 }

internal/streamer/streamer.go

@@ -106,12 +106,12 @@ type RawMessageHandler func(line string)
 // handlerMetrics tracks performance metrics for a handler
 type handlerMetrics struct {
 	processedCount     uint64        // Total messages processed
-	droppedCount       atomic.Uint64 // Total messages dropped; not under mu
+	droppedCount       uint64        // Total messages dropped
 	totalTime          time.Duration // Total processing time (for average calculation)
 	minTime            time.Duration // Minimum processing time
 	maxTime            time.Duration // Maximum processing time
 	queueHighWaterMark int           // Maximum queue length seen
-	mu                 sync.Mutex    // Protects the other metrics
+	mu                 sync.Mutex    // Protects the metrics
 }
 
 // handlerInfo wraps a handler with its queue and metrics
@@ -371,7 +371,7 @@ func (s *Streamer) GetHandlerStats() []HandlerStats {
 			QueueCapacity:      cap(info.queue),
 			QueueHighWaterMark: info.metrics.queueHighWaterMark,
 			ProcessedCount:     info.metrics.processedCount,
-			DroppedCount:       info.metrics.droppedCount.Load(),
+			DroppedCount:       info.metrics.droppedCount,
 			MinProcessTime:     info.metrics.minTime,
 			MaxProcessTime:     info.metrics.maxTime,
 		}
@@ -488,7 +488,7 @@ func (s *Streamer) logMetrics() {
 				"queue_len", len(info.queue),
 				"queue_cap", cap(info.queue),
 				"processed", info.metrics.processedCount,
-				"dropped", info.metrics.droppedCount.Load(),
+				"dropped", info.metrics.droppedCount,
 				"avg_time", avgTime,
 				"min_time", info.metrics.minTime,
 				"max_time", info.metrics.maxTime,
@@ -858,7 +858,7 @@ func (s *Streamer) dispatchMessage(
 		}
 
 		if !s.queueMessage(info, msg) {
-			info.metrics.droppedCount.Add(1)
+			atomic.AddUint64(&info.metrics.droppedCount, 1)
 			s.totalDropped.Add(1)
 
 			continue

internal/streamer/streamer_internal_test.go

@@ -621,68 +621,6 @@ func TestStreamReadsLongLine(t *testing.T) {
 	}
 }
 
-// blockedHandler wants UPDATE messages, has room on its queue for one, and
-// does not return from HandleMessage until release is closed.
-type blockedHandler struct {
-	release chan struct{}
-}
-
-func (blockedHandler) WantsMessage(messageType string) bool {
-	return messageType == ristypes.MessageTypeUpdate
-}
-
-func (blockedHandler) QueueCapacity() int { return 1 }
-
-func (h blockedHandler) HandleMessage(*ristypes.RISMessage) { <-h.release }
-
-// TestHandlerStatsReadWhileMessagesAreDropped has the server send a few UPDATE
-// lines to a blockedHandler, so the read loop drops all but the one the
-// handler holds and the one on its queue, while the test reads the handler's
-// statistics. The drop count must reach the number dropped, and the race
-// detector must find the count read and written safely.
-func TestHandlerStatsReadWhileMessagesAreDropped(t *testing.T) {
-	t.Parallel()
-
-	const (
-		lines       = 5
-		wantDropped = lines - 2
-		maxWait     = 5 * time.Second
-	)
-
-	srv := httptest.NewServer(http.HandlerFunc(
-		func(w http.ResponseWriter, r *http.Request) {
-			_, _ = io.WriteString(w, strings.Repeat(updateLine, lines))
-
-			flush(w)
-			<-r.Context().Done()
-		}))
-	defer srv.Close()
-
-	s := New(logger.New(), metrics.New())
-	s.url = srv.URL
-	handler := blockedHandler{release: make(chan struct{})}
-	s.RegisterHandler(handler)
-
-	err := s.Start(t.Context())
-	if err != nil {
-		t.Fatalf("Start returned error: %v", err)
-	}
-	defer s.Stop(t.Context())
-	defer close(handler.release)
-
-	// The test polls instead of waiting for a signal from the read loop: a
-	// signal would order the drops before the reads here, and the race
-	// detector would have nothing to report.
-	deadline := time.Now().Add(maxWait)
-
-	for s.GetHandlerStats()[0].DroppedCount < wantDropped {
-		if time.Now().After(deadline) {
-			t.Fatalf("fewer than %d messages counted as dropped within %s",
-				wantDropped, maxWait)
-		}
-	}
-}
-
 // TestPeerCountCountsEveryPeerHeardFrom has the server send an UPDATE from
 // stateDownPeer and a KEEPALIVE from another peer, with no OPEN from either,
 // and then a message that ends stateDownPeer's session: a NOTIFICATION, or a