Make sure we log all requests

Before this there would be no logs printed for requests not having
explicit handlers, like when responding "method not allowed" (405) or
"not found" (404).

server/server.go

@@ -752,6 +752,18 @@ func staleLocksFunc(cc *configCache, timeout time.Duration) http.HandlerFunc {
 	}
 }
 
+func methodNotAllowedFunc() http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		http.Error(w, http.StatusText(http.StatusMethodNotAllowed), http.StatusMethodNotAllowed)
+	}
+}
+
+func notFoundFunc() http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		http.NotFound(w, r)
+	}
+}
+
 func writeNewlineJSON(w http.ResponseWriter, b []byte, statusCode int) error {
 	w.Header().Set("content-type", contentTypeString)
 	w.WriteHeader(statusCode)
@@ -1597,6 +1609,9 @@ func Run(configPath string) {
 	// Create middleware chain used for swagger docs endpoint
 	swaggerMiddlewares := newSwaggerMiddlewareChain(hlogMiddlewares)
 
+	// Create middleware chain used for unhandled requests
+	unhandledMiddlewares := newUnhandledChain(hlogMiddlewares)
+
 	preRebootChain := alice.New(fleetLockMiddlewares...).Then(preRebootFunc(cc, timeout))
 	steadyStateChain := alice.New(fleetLockMiddlewares...).Then(steadyStateFunc(cc, timeout))
 
@@ -1617,7 +1632,10 @@ func Run(configPath string) {
 
 	swaggerChain := alice.New(swaggerMiddlewares...).Then(httpSwagger.Handler(httpSwagger.URL(swaggerURL.String())))
 
-	router := newRouter(preRebootChain, steadyStateChain, lockStatusChain, staleLocksChain, apiChain, swaggerChain)
+	methodNotAllowedChain := alice.New(unhandledMiddlewares...).Then(methodNotAllowedFunc())
+	notFoundChain := alice.New(unhandledMiddlewares...).Then(notFoundFunc())
+
+	router := newRouter(methodNotAllowedChain, notFoundChain, preRebootChain, steadyStateChain, lockStatusChain, staleLocksChain, apiChain, swaggerChain)
 
 	srv := &http.Server{
 		Addr:         conf.Server.Listen,
@@ -1723,6 +1741,13 @@ func newSwaggerMiddlewareChain(hlogMiddlewares []alice.Constructor) []alice.Cons
 	return swaggerMiddlewares
 }
 
+func newUnhandledChain(hlogMiddlewares []alice.Constructor) []alice.Constructor {
+	unhandledMiddlewares := []alice.Constructor{}
+	unhandledMiddlewares = append(unhandledMiddlewares, hlogMiddlewares...)
+
+	return unhandledMiddlewares
+}
+
 func newEtcd3Client(conf etcd3config, tlsConfig *tls.Config) (*clientv3.Client, error) {
 	etcd3Config := clientv3.Config{
 		Endpoints:   conf.Endpoints,
@@ -1753,8 +1778,10 @@ func newEtcd3Client(conf etcd3config, tlsConfig *tls.Config) (*clientv3.Client,
 	return etcd3Client, nil
 }
 
-func newRouter(preRebootChain, steadyStateChain, lockStatusChain, staleLocksChain, apiChain http.Handler, swaggerChain http.Handler) *httprouter.Router {
+func newRouter(methodNotAllowedChain, notFoundChain, preRebootChain, steadyStateChain, lockStatusChain, staleLocksChain, apiChain http.Handler, swaggerChain http.Handler) *httprouter.Router {
 	router := httprouter.New()
+	router.MethodNotAllowed = methodNotAllowedChain
+	router.NotFound = notFoundChain
 
 	router.Handler("POST", "/v1/pre-reboot", preRebootChain)
 	router.Handler("POST", "/v1/steady-state", steadyStateChain)