package agent import ( "bytes" "encoding/json" "io" "log" "net" "net/http" "time" ) // HTTPServer is used to wrap an Agent and expose various API's // in a RESTful manner type HTTPServer struct { agent *Agent mux *http.ServeMux listener net.Listener logger *log.Logger } // NewServer starts a new HTTP server to provide an interface to // the agent. func NewServer(agent *Agent, logOutput io.Writer, bind string) (*HTTPServer, error) { // Create the mux mux := http.NewServeMux() // Create listener list, err := net.Listen("tcp", bind) if err != nil { return nil, err } // Create the server srv := &HTTPServer{ agent: agent, mux: mux, listener: list, logger: log.New(logOutput, "", log.LstdFlags), } srv.registerHandlers() // Start the server go http.Serve(list, mux) return srv, nil } // Shutdown is used to shutdown the HTTP server func (s *HTTPServer) Shutdown() { s.listener.Close() } // registerHandlers is used to attach our handlers to the mux func (s *HTTPServer) registerHandlers() { s.mux.HandleFunc("/v1/status/leader", s.wrap(s.StatusLeader)) s.mux.HandleFunc("/v1/status/peers", s.wrap(s.StatusPeers)) s.mux.HandleFunc("/v1/catalog/datacenters", s.wrap(s.CatalogDatacenters)) s.mux.HandleFunc("/v1/catalog/nodes", s.wrap(s.CatalogNodes)) } // wrap is used to wrap functions to make them more convenient func (s *HTTPServer) wrap(handler func(resp http.ResponseWriter, req *http.Request) (interface{}, error)) func(resp http.ResponseWriter, req *http.Request) { f := func(resp http.ResponseWriter, req *http.Request) { // Invoke the handler start := time.Now() defer func() { s.logger.Printf("[DEBUG] HTTP Request %v (%v)", req.URL, time.Now().Sub(start)) }() obj, err := handler(resp, req) // Check for an error HAS_ERR: if err != nil { s.logger.Printf("[ERR] Request %v, error: %v", req, err) resp.WriteHeader(500) resp.Write([]byte(err.Error())) return } // Write out the JSON object if obj != nil { var buf bytes.Buffer enc := json.NewEncoder(&buf) if err = enc.Encode(obj); err != nil { goto HAS_ERR } resp.Write(buf.Bytes()) } } return f } // decodeBody is used to decode a JSON request body func decodeBody(req *http.Request, out interface{}) error { dec := json.NewDecoder(req.Body) return dec.Decode(out) }