diff options
Diffstat (limited to 'modules/caddyhttp')
| -rw-r--r-- | modules/caddyhttp/reverseproxy/reverseproxy.go | 72 | ||||
| -rw-r--r-- | modules/caddyhttp/subroute.go | 30 |
2 files changed, 87 insertions, 15 deletions
diff --git a/modules/caddyhttp/reverseproxy/reverseproxy.go b/modules/caddyhttp/reverseproxy/reverseproxy.go index 8137237..507995f 100644 --- a/modules/caddyhttp/reverseproxy/reverseproxy.go +++ b/modules/caddyhttp/reverseproxy/reverseproxy.go @@ -94,6 +94,20 @@ type Handler struct { // be avoided if at all possible for performance reasons. BufferRequests bool `json:"buffer_requests,omitempty"` + // List of handlers and their associated matchers to evaluate + // after successful roundtrips. The first handler that matches + // the response from a backend will be invoked. The response + // body from the backend will not be written to the client; + // it is up to the handler to finish handling the response. + // If passive health checks are enabled, any errors from the + // handler chain will not affect the health status of the + // backend. + // + // Two new placeholders are available in this handler chain: + // - `{http.reverse_proxy.status_code}` The status code + // - `{http.reverse_proxy.status_text}` The status text + HandleResponse []caddyhttp.ResponseHandler `json:"handle_response,omitempty"` + Transport http.RoundTripper `json:"-"` CB CircuitBreaker `json:"-"` @@ -252,6 +266,14 @@ func (h *Handler) Provision(ctx caddy.Context) error { go h.activeHealthChecker() } + // set up any response routes + for i, rh := range h.HandleResponse { + err := rh.Provision(ctx) + if err != nil { + return fmt.Errorf("provisioning response handler %d: %v", i, err) + } + } + return nil } @@ -361,13 +383,21 @@ func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyht } // proxy the request to that upstream - proxyErr = h.reverseProxy(w, r, dialInfo) + proxyErr = h.reverseProxy(w, r, dialInfo, next) if proxyErr == nil || proxyErr == context.Canceled { // context.Canceled happens when the downstream client // cancels the request, which is not our failure return nil } + // if the roundtrip was successful, don't retry the request or + // ding the health status of the upstream (an error can still + // occur after the roundtrip if, for example, a response handler + // after the roundtrip returns an error) + if succ, ok := proxyErr.(roundtripSucceeded); ok { + return succ.error + } + // remember this failure (if enabled) h.countFailure(upstream) @@ -456,7 +486,7 @@ func (h Handler) prepareRequest(req *http.Request) error { // reverseProxy performs a round-trip to the given backend and processes the response with the client. // (This method is mostly the beginning of what was borrowed from the net/http/httputil package in the // Go standard library which was used as the foundation.) -func (h *Handler) reverseProxy(rw http.ResponseWriter, req *http.Request, di DialInfo) error { +func (h *Handler) reverseProxy(rw http.ResponseWriter, req *http.Request, di DialInfo, next caddyhttp.Handler) error { di.Upstream.Host.CountRequest(1) defer di.Upstream.Host.CountRequest(-1) @@ -471,16 +501,14 @@ func (h *Handler) reverseProxy(rw http.ResponseWriter, req *http.Request, di Dia logger := h.logger.With( zap.String("upstream", di.Upstream.String()), zap.Object("request", caddyhttp.LoggableHTTPRequest{Request: req}), - zap.Duration("duration", duration), - ) + zap.Duration("duration", duration)) if err != nil { logger.Debug("upstream roundtrip", zap.Error(err)) return err } logger.Debug("upstream roundtrip", zap.Object("headers", caddyhttp.LoggableHTTPHeader(res.Header)), - zap.Int("status", res.StatusCode), - ) + zap.Int("status", res.StatusCode)) // update circuit breaker on current conditions if di.Upstream.cb != nil { @@ -503,6 +531,25 @@ func (h *Handler) reverseProxy(rw http.ResponseWriter, req *http.Request, di Dia } } + for i, rh := range h.HandleResponse { + if len(rh.Routes) == 0 { + continue + } + if rh.Match != nil && !rh.Match.Match(res.StatusCode, res.Header) { + continue + } + res.Body.Close() + repl := req.Context().Value(caddy.ReplacerCtxKey).(*caddy.Replacer) + repl.Set("http.reverse_proxy.status_code", res.StatusCode) + repl.Set("http.reverse_proxy.status_text", res.Status) + h.logger.Debug("handling response", zap.Int("handler", i)) + if routeErr := rh.Routes.Compile(next).ServeHTTP(rw, req); routeErr != nil { + // wrap error in roundtripSucceeded so caller knows that + // the roundtrip was successful and to not retry + return roundtripSucceeded{routeErr} + } + } + // Deal with 101 Switching Protocols responses: (WebSocket, h2c, etc) if res.StatusCode == http.StatusSwitchingProtocols { h.handleUpgradeResponse(rw, req, res) @@ -537,15 +584,6 @@ func (h *Handler) reverseProxy(rw http.ResponseWriter, req *http.Request, di Dia rw.Header().Add("Trailer", strings.Join(trailerKeys, ", ")) } - // TODO: there should be an option to return an error if the response - // matches some criteria; would solve https://github.com/caddyserver/caddy/issues/1447 - // by allowing the backend to determine whether this server should treat - // a 400+ status code as an error -- but we might need to be careful that - // we do not affect the health status of the backend... still looking into - // that; if we need to avoid that, we should return a particular error type - // that the caller of this function checks for and only applies health - // status changes if the error is not this special type - rw.WriteHeader(res.StatusCode) err = h.copyResponse(rw, res.Body, h.flushInterval(req, res)) @@ -782,6 +820,10 @@ type TLSTransport interface { EnableTLS(base *TLSConfig) error } +// roundtripSucceeded is an error type that is returned if the +// roundtrip succeeded, but an error occurred after-the-fact. +type roundtripSucceeded struct{ error } + var bufPool = sync.Pool{ New: func() interface{} { return new(bytes.Buffer) diff --git a/modules/caddyhttp/subroute.go b/modules/caddyhttp/subroute.go index 2e80d88..b1700f5 100644 --- a/modules/caddyhttp/subroute.go +++ b/modules/caddyhttp/subroute.go @@ -80,6 +80,36 @@ func (sr *Subroute) ServeHTTP(w http.ResponseWriter, r *http.Request, next Handl return err } +// ResponseHandler pairs a response matcher with a route list. +// It is useful for executing handler routes based on the +// properties of an HTTP response that has not been written +// out to the client yet. +// +// To use this type, provision it at module load time, then +// when ready to use, match the response against its matcher; +// if it matches (or doesn't have a matcher), invoke the routes +// by calling `rh.Routes.Compile(next).ServeHTTP(rw, req)` (or +// similar). +type ResponseHandler struct { + // The response matcher for this handler. If empty/nil, + // it always matches. + Match *ResponseMatcher `json:"match,omitempty"` + + // The list of HTTP routes to execute. + Routes RouteList `json:"routes,omitempty"` +} + +// Provision sets up the routse in rh. +func (rh *ResponseHandler) Provision(ctx caddy.Context) error { + if rh.Routes != nil { + err := rh.Routes.Provision(ctx) + if err != nil { + return err + } + } + return nil +} + // Interface guards var ( _ caddy.Provisioner = (*Subroute)(nil) |