X-Git-Url: http://git.scottworley.com/reliable-chat/blobdiff_plain/87ac1d98245de076b321b149cf8c36795f4425e6..7310ffeebfda8540d2113fc8c846971a0f913d57:/server/server.go?ds=sidebyside diff --git a/server/server.go b/server/server.go index 8c8a989..963931f 100644 --- a/server/server.go +++ b/server/server.go @@ -1,70 +1,140 @@ +/* reliable-chat - multipath chat + * Copyright (C) 2012 Scott Worley + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU Affero General Public License as + * published by the Free Software Foundation, either version 3 of the + * License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Affero General Public License for more details. + * + * You should have received a copy of the GNU Affero General Public License + * along with this program. If not, see . + */ + package main import "container/list" import "encoding/json" +import "expvar" +import "flag" import "log" import "net/http" +import "strconv" import "time" +var port = flag.Int("port", 21059, "Port to listen on") +var localaddress = flag.String("localaddress", "", "Local address to bind to") +var max_messages = flag.Int("maxmessages", 1000, "Maximum number of messages to retain") + +var start_time = expvar.NewInt("start_time") +var speak_count = expvar.NewInt("speak_count") +var fetch_count = expvar.NewInt("fetch_count") +var fetch_wait_count = expvar.NewInt("fetch_wait_count") +var fetch_wake_count = expvar.NewInt("fetch_wake_count") +var drop_due_to_limit_count = expvar.NewInt("drop_due_to_limit_count") + type Message struct { Time time.Time + ID string Text string } -type FetchResponse struct { - Messages []Message - Time time.Time -} - type StoreRequest struct { StartTime time.Time Messages chan<- []Message } type Store struct { - Add chan Message - Get chan StoreRequest + Add chan *Message + Get chan *StoreRequest } -// TODO: Monotonic clock +var monotonic_clock chan chan time.Time + +const minimum_clock_increment = time.Millisecond + +func start_clock() { + internal_monotonic_clock := make(chan chan time.Time, 1) + go func() { + last_time := time.Now() + main: + for { + select { + case request, ok := <-internal_monotonic_clock: + if !ok { + break main + } + earliest_acceptable_time := last_time.Add(minimum_clock_increment) + current_time := time.Now() + if current_time.Before(earliest_acceptable_time) { + current_time = earliest_acceptable_time + } + request <- current_time + last_time = current_time + } + } + }() + monotonic_clock = internal_monotonic_clock +} + +func now() time.Time { + c := make(chan time.Time, 0) + monotonic_clock <- c + return <-c +} func manage_store(store Store) { messages := list.New() message_count := 0 - max_messages := 1000 waiting := list.New() +main: for { select { - case new_message := <-store.Add: - messages.PushBack(new_message) + case new_message, ok := <-store.Add: + if !ok { + break main + } + speak_count.Add(1) for waiter := waiting.Front(); waiter != nil; waiter = waiter.Next() { - waiter.Value.(StoreRequest).Messages <- []Message{new_message} - close(waiter.Value.(StoreRequest).Messages) + waiter.Value.(*StoreRequest).Messages <- []Message{*new_message} + close(waiter.Value.(*StoreRequest).Messages) + fetch_wake_count.Add(1) } waiting.Init() - if message_count < max_messages { + messages.PushBack(new_message) + if message_count < *max_messages { message_count++ } else { messages.Remove(messages.Front()) + drop_due_to_limit_count.Add(1) + } + case request, ok := <-store.Get: + if !ok { + break main } - case request := <-store.Get: - if messages.Back() == nil || request.StartTime.After(messages.Back().Value.(Message).Time) { + fetch_count.Add(1) + if messages.Back() == nil || !request.StartTime.Before(messages.Back().Value.(*Message).Time) { waiting.PushBack(request) + fetch_wait_count.Add(1) } else { start := messages.Back() response_size := 1 - if messages.Front().Value.(Message).Time.After(request.StartTime) { + if messages.Front().Value.(*Message).Time.After(request.StartTime) { start = messages.Front() response_size = message_count } else { - for start.Prev().Value.(Message).Time.After(request.StartTime) { + for start.Prev().Value.(*Message).Time.After(request.StartTime) { start = start.Prev() response_size++ } } response_messages := make([]Message, 0, response_size) for m := start; m != nil; m = m.Next() { - response_messages = append(response_messages, m.Value.(Message)) + response_messages = append(response_messages, *m.Value.(*Message)) } request.Messages <- response_messages } @@ -73,11 +143,15 @@ func manage_store(store Store) { } func start_store() Store { - store := Store{make(chan Message, 20), make(chan StoreRequest, 20)} + store := Store{make(chan *Message, 20), make(chan *StoreRequest, 20)} go manage_store(store) return store } +const robots_txt = `User-agent: * +Disallow: / +` + func start_server(store Store) { http.HandleFunc("/fetch", func(w http.ResponseWriter, r *http.Request) { var since time.Time @@ -92,26 +166,38 @@ func start_server(store Store) { } } messages_from_store := make(chan []Message, 1) - store.Get <- StoreRequest{since, messages_from_store} + store.Get <- &StoreRequest{since, messages_from_store} - json_encoded, err := json.Marshal(FetchResponse{<-messages_from_store, time.Now()}) + json_encoded, err := json.Marshal(<-messages_from_store) if err != nil { log.Print("json encode: ", err) w.WriteHeader(http.StatusInternalServerError) return } w.Header().Add("Content-Type", "application/json") + w.Header().Add("Access-Control-Allow-Origin", "*") w.Write(json_encoded) }) http.HandleFunc("/speak", func(w http.ResponseWriter, r *http.Request) { - store.Add <- Message{time.Now(), r.FormValue("text")} + store.Add <- &Message{ + now(), + r.FormValue("id"), + r.FormValue("text")} + w.Header().Add("Access-Control-Allow-Origin", "*") + }) + + http.HandleFunc("/robots.txt", func(w http.ResponseWriter, r *http.Request) { + w.Write([]byte(robots_txt)) }) - log.Fatal(http.ListenAndServe(":8080", nil)) + log.Fatal(http.ListenAndServe(*localaddress+":"+strconv.Itoa(*port), nil)) } func main() { + flag.Parse() + start_clock() + start_time.Set(now().UnixNano()) store := start_store() start_server(store) }