package agent import ( "encoding/json" "fmt" "net" "net/http" "net/http/pprof" "net/url" "regexp" "strconv" "strings" "time" "github.com/armon/go-metrics" "github.com/hashicorp/consul/acl" "github.com/hashicorp/consul/agent/structs" "github.com/mitchellh/mapstructure" ) // MethodNotAllowedError should be returned by a handler when the HTTP method is not allowed. type MethodNotAllowedError struct { Method string Allow []string } func (e MethodNotAllowedError) Error() string { return fmt.Sprintf("method %s not allowed", e.Method) } // HTTPServer provides an HTTP api for an agent. type HTTPServer struct { *http.Server ln net.Listener agent *Agent blacklist *Blacklist // proto is filled by the agent to "http" or "https". proto string } // endpoint is a Consul-specific HTTP handler that takes the usual arguments in // but returns a response object and error, both of which are handled in a // common manner by Consul's HTTP server. type endpoint func(resp http.ResponseWriter, req *http.Request) (interface{}, error) // unboundEndpoint is an endpoint method on a server. type unboundEndpoint func(s *HTTPServer, resp http.ResponseWriter, req *http.Request) (interface{}, error) // endpoints is a map from URL pattern to unbound endpoint. var endpoints map[string]unboundEndpoint // registerEndpoint registers a new endpoint, which should be done at package // init() time. func registerEndpoint(pattern string, fn unboundEndpoint) { if endpoints == nil { endpoints = make(map[string]unboundEndpoint) } if endpoints[pattern] != nil { panic(fmt.Errorf("Pattern %q is already registered", pattern)) } endpoints[pattern] = fn } // handler is used to attach our handlers to the mux func (s *HTTPServer) handler(enableDebug bool) http.Handler { mux := http.NewServeMux() // handleFuncMetrics takes the given pattern and handler and wraps to produce // metrics based on the pattern and request. handleFuncMetrics := func(pattern string, handler http.HandlerFunc) { // Get the parts of the pattern. We omit any initial empty for the // leading slash, and put an underscore as a "thing" placeholder if we // see a trailing slash, which means the part after is parsed. This lets // us distinguish from things like /v1/query and /v1/query/. var parts []string for i, part := range strings.Split(pattern, "/") { if part == "" { if i == 0 { continue } part = "_" } parts = append(parts, part) } // Register the wrapper, which will close over the expensive-to-compute // parts from above. // TODO (kyhavlov): Convert this to utilize metric labels in a major release wrapper := func(resp http.ResponseWriter, req *http.Request) { start := time.Now() handler(resp, req) key := append([]string{"http", req.Method}, parts...) metrics.MeasureSince(append([]string{"consul"}, key...), start) metrics.MeasureSince(key, start) } mux.HandleFunc(pattern, wrapper) } mux.HandleFunc("/", s.Index) for pattern, fn := range endpoints { thisFn := fn bound := func(resp http.ResponseWriter, req *http.Request) (interface{}, error) { return thisFn(s, resp, req) } handleFuncMetrics(pattern, s.wrap(bound)) } if enableDebug { handleFuncMetrics("/debug/pprof/", pprof.Index) handleFuncMetrics("/debug/pprof/cmdline", pprof.Cmdline) handleFuncMetrics("/debug/pprof/profile", pprof.Profile) handleFuncMetrics("/debug/pprof/symbol", pprof.Symbol) } // Use the custom UI dir if provided. if s.agent.config.UIDir != "" { mux.Handle("/ui/", http.StripPrefix("/ui/", http.FileServer(http.Dir(s.agent.config.UIDir)))) } else if s.agent.config.EnableUI { mux.Handle("/ui/", http.StripPrefix("/ui/", http.FileServer(assetFS()))) } return mux } // aclEndpointRE is used to find old ACL endpoints that take tokens in the URL // so that we can redact them. The ACL endpoints that take the token in the URL // are all of the form /v1/acl//, and can optionally include query // parameters which are indicated by a question mark. We capture the part before // the token, the token, and any query parameters after, and then reassemble as // $1$3 (the token in $2 isn't used), which will give: // // /v1/acl/clone/foo -> /v1/acl/clone/ // /v1/acl/clone/foo?token=bar -> /v1/acl/clone/?token= // // The query parameter in the example above is obfuscated like any other, after // this regular expression is applied, so the regular expression substitution // results in: // // /v1/acl/clone/foo?token=bar -> /v1/acl/clone/?token=bar // ^---- $1 ----^^- $2 -^^-- $3 --^ // // And then the loop that looks for parameters called "token" does the last // step to get to the final redacted form. var ( aclEndpointRE = regexp.MustCompile("^(/v1/acl/[^/]+/)([^?]+)([?]?.*)$") ) // wrap is used to wrap functions to make them more convenient func (s *HTTPServer) wrap(handler endpoint) http.HandlerFunc { return func(resp http.ResponseWriter, req *http.Request) { setHeaders(resp, s.agent.config.HTTPResponseHeaders) setTranslateAddr(resp, s.agent.config.TranslateWANAddrs) // Obfuscate any tokens from appearing in the logs formVals, err := url.ParseQuery(req.URL.RawQuery) if err != nil { s.agent.logger.Printf("[ERR] http: Failed to decode query: %s from=%s", err, req.RemoteAddr) resp.WriteHeader(http.StatusInternalServerError) return } logURL := req.URL.String() if tokens, ok := formVals["token"]; ok { for _, token := range tokens { if token == "" { logURL += "" continue } logURL = strings.Replace(logURL, token, "", -1) } } logURL = aclEndpointRE.ReplaceAllString(logURL, "$1$3") if s.blacklist.Block(req.URL.Path) { errMsg := "Endpoint is blocked by agent configuration" s.agent.logger.Printf("[ERR] http: Request %s %v, error: %v from=%s", req.Method, logURL, err, req.RemoteAddr) resp.WriteHeader(http.StatusForbidden) fmt.Fprint(resp, errMsg) return } isMethodNotAllowed := func(err error) bool { _, ok := err.(MethodNotAllowedError) return ok } handleErr := func(err error) { s.agent.logger.Printf("[ERR] http: Request %s %v, error: %v from=%s", req.Method, logURL, err, req.RemoteAddr) switch { case acl.IsErrPermissionDenied(err) || acl.IsErrNotFound(err): resp.WriteHeader(http.StatusForbidden) fmt.Fprint(resp, err.Error()) case structs.IsErrRPCRateExceeded(err): resp.WriteHeader(http.StatusTooManyRequests) case isMethodNotAllowed(err): // RFC2616 states that for 405 Method Not Allowed the response // MUST include an Allow header containing the list of valid // methods for the requested resource. // https://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html resp.Header()["Allow"] = err.(MethodNotAllowedError).Allow resp.WriteHeader(http.StatusMethodNotAllowed) // 405 fmt.Fprint(resp, err.Error()) default: resp.WriteHeader(http.StatusInternalServerError) fmt.Fprint(resp, err.Error()) } } // Invoke the handler start := time.Now() defer func() { s.agent.logger.Printf("[DEBUG] http: Request %s %v (%v) from=%s", req.Method, logURL, time.Since(start), req.RemoteAddr) }() obj, err := handler(resp, req) if err != nil { handleErr(err) return } if obj == nil { return } buf, err := s.marshalJSON(req, obj) if err != nil { handleErr(err) return } resp.Header().Set("Content-Type", "application/json") resp.Write(buf) } } // marshalJSON marshals the object into JSON, respecting the user's pretty-ness // configuration. func (s *HTTPServer) marshalJSON(req *http.Request, obj interface{}) ([]byte, error) { if _, ok := req.URL.Query()["pretty"]; ok || s.agent.config.DevMode { buf, err := json.MarshalIndent(obj, "", " ") if err != nil { return nil, err } buf = append(buf, "\n"...) return buf, nil } buf, err := json.Marshal(obj) if err != nil { return nil, err } return buf, err } // Returns true if the UI is enabled. func (s *HTTPServer) IsUIEnabled() bool { return s.agent.config.UIDir != "" || s.agent.config.EnableUI } // Renders a simple index page func (s *HTTPServer) Index(resp http.ResponseWriter, req *http.Request) { // Check if this is a non-index path if req.URL.Path != "/" { resp.WriteHeader(http.StatusNotFound) return } // Give them something helpful if there's no UI so they at least know // what this server is. if !s.IsUIEnabled() { fmt.Fprint(resp, "Consul Agent") return } // Redirect to the UI endpoint http.Redirect(resp, req, "/ui/", http.StatusMovedPermanently) // 301 } // decodeBody is used to decode a JSON request body func decodeBody(req *http.Request, out interface{}, cb func(interface{}) error) error { var raw interface{} dec := json.NewDecoder(req.Body) if err := dec.Decode(&raw); err != nil { return err } // Invoke the callback prior to decode if cb != nil { if err := cb(raw); err != nil { return err } } return mapstructure.Decode(raw, out) } // setTranslateAddr is used to set the address translation header. This is only // present if the feature is active. func setTranslateAddr(resp http.ResponseWriter, active bool) { if active { resp.Header().Set("X-Consul-Translate-Addresses", "true") } } // setIndex is used to set the index response header func setIndex(resp http.ResponseWriter, index uint64) { resp.Header().Set("X-Consul-Index", strconv.FormatUint(index, 10)) } // setKnownLeader is used to set the known leader header func setKnownLeader(resp http.ResponseWriter, known bool) { s := "true" if !known { s = "false" } resp.Header().Set("X-Consul-KnownLeader", s) } // setLastContact is used to set the last contact header func setLastContact(resp http.ResponseWriter, last time.Duration) { if last < 0 { last = 0 } lastMsec := uint64(last / time.Millisecond) resp.Header().Set("X-Consul-LastContact", strconv.FormatUint(lastMsec, 10)) } // setMeta is used to set the query response meta data func setMeta(resp http.ResponseWriter, m *structs.QueryMeta) { setIndex(resp, m.Index) setLastContact(resp, m.LastContact) setKnownLeader(resp, m.KnownLeader) } // setHeaders is used to set canonical response header fields func setHeaders(resp http.ResponseWriter, headers map[string]string) { for field, value := range headers { resp.Header().Set(http.CanonicalHeaderKey(field), value) } } // parseWait is used to parse the ?wait and ?index query params // Returns true on error func parseWait(resp http.ResponseWriter, req *http.Request, b *structs.QueryOptions) bool { query := req.URL.Query() if wait := query.Get("wait"); wait != "" { dur, err := time.ParseDuration(wait) if err != nil { resp.WriteHeader(http.StatusBadRequest) fmt.Fprint(resp, "Invalid wait time") return true } b.MaxQueryTime = dur } if idx := query.Get("index"); idx != "" { index, err := strconv.ParseUint(idx, 10, 64) if err != nil { resp.WriteHeader(http.StatusBadRequest) fmt.Fprint(resp, "Invalid index") return true } b.MinQueryIndex = index } return false } // parseConsistency is used to parse the ?stale and ?consistent query params. // Returns true on error func parseConsistency(resp http.ResponseWriter, req *http.Request, b *structs.QueryOptions) bool { query := req.URL.Query() if _, ok := query["stale"]; ok { b.AllowStale = true } if _, ok := query["consistent"]; ok { b.RequireConsistent = true } if b.AllowStale && b.RequireConsistent { resp.WriteHeader(http.StatusBadRequest) fmt.Fprint(resp, "Cannot specify ?stale with ?consistent, conflicting semantics.") return true } return false } // parseDC is used to parse the ?dc query param func (s *HTTPServer) parseDC(req *http.Request, dc *string) { if other := req.URL.Query().Get("dc"); other != "" { *dc = other } else if *dc == "" { *dc = s.agent.config.Datacenter } } // parseToken is used to parse the ?token query param or the X-Consul-Token header func (s *HTTPServer) parseToken(req *http.Request, token *string) { if other := req.URL.Query().Get("token"); other != "" { *token = other return } if other := req.Header.Get("X-Consul-Token"); other != "" { *token = other return } // Set the default ACLToken *token = s.agent.tokens.UserToken() } // parseSource is used to parse the ?near= query parameter, used for // sorting by RTT based on a source node. We set the source's DC to the target // DC in the request, if given, or else the agent's DC. func (s *HTTPServer) parseSource(req *http.Request, source *structs.QuerySource) { s.parseDC(req, &source.Datacenter) if node := req.URL.Query().Get("near"); node != "" { if node == "_agent" { source.Node = s.agent.config.NodeName } else { source.Node = node } } } // parseMetaFilter is used to parse the ?node-meta=key:value query parameter, used for // filtering results to nodes with the given metadata key/value func (s *HTTPServer) parseMetaFilter(req *http.Request) map[string]string { if filterList, ok := req.URL.Query()["node-meta"]; ok { filters := make(map[string]string) for _, filter := range filterList { key, value := ParseMetaPair(filter) filters[key] = value } return filters } return nil } // parse is a convenience method for endpoints that need // to use both parseWait and parseDC. func (s *HTTPServer) parse(resp http.ResponseWriter, req *http.Request, dc *string, b *structs.QueryOptions) bool { s.parseDC(req, dc) s.parseToken(req, &b.Token) if parseConsistency(resp, req, b) { return true } return parseWait(resp, req, b) }