package main import ( "bufio" "encoding/csv" "errors" "fmt" "log" "math/rand" "os" "path/filepath" "strconv" "strings" "sync" "time" "github.com/dirtbags/moth/pkg/award" "github.com/spf13/afero" ) // DistinguishableChars are visually unambiguous glyphs. // People with mediocre handwriting could write these down unambiguously, // and they can be entered without holding down shift. const DistinguishableChars = "34678abcdefhikmnpqrtwxy=" // RFC3339Space is a time layout which replaces 'T' with a space. // This is also a valid RFC3339 format. const RFC3339Space = "2006-01-02 15:04:05Z07:00" // TeamLinkPrefix is prepended to a Team ID and stored as a team name // to handle "linked" team IDs, used for participant ID to team mapping. const TeamLinkPrefix = "link>" // ErrAlreadyRegistered means a team cannot be registered because it was registered previously. var ErrAlreadyRegistered = errors.New("team ID has already been registered") // State defines the current state of a MOTH instance. // We use the filesystem for synchronization between threads. // The only thing State methods need to know is the path to the state directory. type State struct { afero.Fs // Enabled tracks whether the current State system is processing updates Enabled bool enabledWhy string refreshNow chan bool eventStream chan []string eventWriter *csv.Writer eventWriterFile afero.File // Caches, so we're not hammering NFS with metadata operations teamsLastChange time.Time teams map[string]Team pointsLog award.List messages string lock sync.RWMutex } // NewState returns a new State struct backed by the given Fs func NewState(fs afero.Fs) *State { s := &State{ Fs: fs, Enabled: true, refreshNow: make(chan bool, 5), eventStream: make(chan []string, 80), teams: make(map[string]Team), } if err := s.reopenEventLog(); err != nil { log.Fatal(err) } return s } // updateEnabled checks a few things to see if this state directory is "enabled". func (s *State) updateEnabled() { nextEnabled := true why := "state/hours.txt has no timestamps before now" if untilFile, err := s.Open("hours.txt"); err == nil { defer untilFile.Close() scanner := bufio.NewScanner(untilFile) for scanner.Scan() { line := scanner.Text() if len(line) < 1 { continue } thisEnabled := true switch line[0] { case '+': thisEnabled = true line = line[1:] case '-': thisEnabled = false line = line[1:] case '#': continue default: log.Println("state/hours.txt has bad line:", line) } line, _, _ = strings.Cut(line, "#") // Remove inline comments line = strings.TrimSpace(line) until := time.Time{} if len(line) == 0 { // Let it stay as zero time, so it's always before now } else if until, err = time.Parse(time.RFC3339, line); err == nil { // Great, it was RFC 3339 } else if until, err = time.Parse(RFC3339Space, line); err == nil { // Great, it was RFC 3339 with a space instead of a 'T' } else { log.Println("state/hours.txt has bad timestamp:", line) continue } if until.Before(time.Now()) { nextEnabled = thisEnabled why = fmt.Sprint("state/hours.txt most recent timestamp:", line) } } } if (nextEnabled != s.Enabled) || (why != s.enabledWhy) { s.Enabled = nextEnabled s.enabledWhy = why log.Printf("Setting enabled=%v: %s", s.Enabled, s.enabledWhy) if s.Enabled { s.LogEvent("enabled", "", "", 0, s.enabledWhy) } else { s.LogEvent("disabled", "", "", 0, s.enabledWhy) } } } // TeamName returns a Team given a team ID. // // The returned team ID will be the dereferenced filename of the team. // This allows you to have symbolic links to team IDs, // in order to implement participant IDs func (s *State) TeamName(teamID string) (Team, error) { s.lock.RLock() team, ok := s.teams[teamID] s.lock.RUnlock() if !ok { return Team{}, fmt.Errorf("unregistered team ID: %s", teamID) } return team, nil } // SetTeamName writes out team name. // This can only be done once per team. func (s *State) SetTeamName(teamID, teamName string) error { s.lock.RLock() _, ok := s.teams[teamID] s.lock.RUnlock() if ok { return ErrAlreadyRegistered } idsFile, err := s.Open("teamids.txt") if err != nil { return fmt.Errorf("team IDs file does not exist") } defer idsFile.Close() found := false scanner := bufio.NewScanner(idsFile) for scanner.Scan() { if scanner.Text() == teamID { found = true break } } if !found { return fmt.Errorf("team ID not found in list of valid team IDs") } for strings.HasPrefix(teamName, TeamLinkPrefix) { teamName = teamName[len(TeamLinkPrefix):] } teamFilename := filepath.Join("teams", teamID) teamFile, err := s.Fs.OpenFile(teamFilename, os.O_CREATE|os.O_WRONLY|os.O_EXCL, 0644) if os.IsExist(err) { return ErrAlreadyRegistered } else if err != nil { return err } defer teamFile.Close() log.Printf("Setting team name [%s] in file %s", teamName, teamFilename) fmt.Fprintln(teamFile, teamName) teamFile.Close() s.refreshNow <- true return nil } // PointsLog retrieves the current points log. func (s *State) PointsLog() award.List { s.lock.RLock() ret := make(award.List, len(s.pointsLog)) copy(ret, s.pointsLog) s.lock.RUnlock() return ret } // Messages retrieves the current messages. func (s *State) Messages() string { s.lock.RLock() // It's not clear to me that this actually needs to happen defer s.lock.RUnlock() return s.messages } // AwardPoints gives points to team in category. // This doesn't attempt to ensure the team ID has been registered. // It first checks to make sure these are not duplicate points. // This is not a perfect check, you can trigger a race condition here. // It's just a courtesy to the user. // The update task makes sure we never have duplicate points in the log. func (s *State) AwardPoints(team Team, category string, points int) error { return s.awardPointsAtTime(time.Now().Unix(), team, category, points) } func (s *State) awardPointsAtTime(when int64, team Team, category string, points int) error { a := award.T{ When: when, TeamID: team.ID, Category: category, Points: points, } for _, e := range s.PointsLog() { if a.Equal(e) { return fmt.Errorf("points already awarded to this team in this category") } } //fn := fmt.Sprintf("%s-%s-%d", a.TeamID, a.Category, a.Points) fn := a.Filename() tmpfn := filepath.Join("points.tmp", fn) newfn := filepath.Join("points.new", fn) if err := afero.WriteFile(s, tmpfn, []byte(a.String()), 0644); err != nil { return err } if err := s.Rename(tmpfn, newfn); err != nil { return err } // State should be updated immediately s.refreshNow <- true return nil } // collectPoints gathers up files in points.new/ and appends their contents to points.log, // removing each points.new/ file as it goes. func (s *State) collectPoints() { files, err := afero.ReadDir(s, "points.new") if err != nil { log.Print(err) return } for _, f := range files { filename := filepath.Join("points.new", f.Name()) awardstr, err := afero.ReadFile(s, filename) if err != nil { log.Print("Opening new points: ", err) continue } awd, err := award.Parse(string(awardstr)) if err != nil { log.Print("Can't parse award file ", filename, ": ", err) continue } duplicate := false s.lock.RLock() for _, e := range s.pointsLog { if awd.Equal(e) { duplicate = true break } } s.lock.RUnlock() if duplicate { log.Print("Skipping duplicate points: ", awd.String()) } else { log.Print("Award: ", awd.String()) logf, err := s.OpenFile("points.log", os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644) if err != nil { log.Print("Can't append to points log: ", err) return } fmt.Fprintln(logf, awd.String()) logf.Close() // Stick this on the cache too s.lock.Lock() s.pointsLog = append(s.pointsLog, awd) s.lock.Unlock() } if err := s.Remove(filename); err != nil { log.Print("Unable to remove new points file: ", err) } } } func (s *State) maybeInitialize() { // Are we supposed to re-initialize? if _, err := s.Stat("initialized"); !os.IsNotExist(err) { return } now := time.Now().UTC().Format(time.RFC3339) log.Print("initialized file missing, re-initializing") // Remove any extant control and state files s.Remove("enabled") s.Remove("hours.txt") s.Remove("points.log") s.Remove("events.csv") s.Remove("messages.html") s.Remove("mothd.log") s.RemoveAll("points.tmp") s.RemoveAll("points.new") s.RemoveAll("teams") // Open log file if err := s.reopenEventLog(); err != nil { log.Fatal(err) } s.LogEvent("init", "", "", 0) // Make sure various subdirectories exist s.Mkdir("points.tmp", 0755) s.Mkdir("points.new", 0755) s.Mkdir("teams", 0755) // Preseed available team ids if file doesn't exist if f, err := s.OpenFile("teamids.txt", os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0644); err == nil { id := make([]byte, 8) for i := 0; i < 100; i++ { for i := range id { char := rand.Intn(len(DistinguishableChars)) id[i] = DistinguishableChars[char] } fmt.Fprintln(f, string(id)) } f.Close() } // Create some files if f, err := s.Create("initialized"); err == nil { fmt.Fprintln(f, "initialized: remove to re-initialize the contest.") fmt.Fprintln(f) fmt.Fprintln(f, "This instance was initialized at", now) f.Close() } if f, err := s.Create("hours.txt"); err == nil { fmt.Fprintln(f, "# hours.txt: when the contest is enabled") fmt.Fprintln(f, "#") fmt.Fprintln(f, "# Enable: + [timestamp]") fmt.Fprintln(f, "# Disable: - [timestamp]") fmt.Fprintln(f, "#") fmt.Fprintln(f, "# This file, and all files in this directory, are re-read periodically.") fmt.Fprintln(f, "# Default is enabled.") fmt.Fprintln(f, "# Rules with only '-' or '+' are also allowed.") fmt.Fprintln(f, "# Rules apply from the top down.") fmt.Fprintln(f, "# If you put something in out of order, it's going to be bonkers.") fmt.Fprintln(f) fmt.Fprintln(f, "- 1970-01-01T00:00:00Z") fmt.Fprintln(f, "+", now) fmt.Fprintln(f, "- 2519-10-31T00:00:00Z") f.Close() } if f, err := s.Create("messages.html"); err == nil { fmt.Fprintln(f, "") f.Close() } if f, err := s.Create("points.log"); err == nil { f.Close() } } // LogEvent writes to the event log func (s *State) LogEvent(event, teamID, cat string, points int, extra ...string) { s.eventStream <- append( []string{ strconv.FormatInt(time.Now().Unix(), 10), event, teamID, cat, strconv.Itoa(points), }, extra..., ) } func (s *State) reopenEventLog() error { if s.eventWriter != nil { s.eventWriter.Flush() } if s.eventWriterFile != nil { if err := s.eventWriterFile.Close(); err != nil { // We're going to soldier on if Close returns error log.Print(err) } } eventWriterFile, err := s.OpenFile("events.csv", os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644) if err != nil { return err } s.eventWriterFile = eventWriterFile s.eventWriter = csv.NewWriter(s.eventWriterFile) return nil } func (s *State) updateCaches() { s.lock.Lock() defer s.lock.Unlock() if f, err := s.Open("points.log"); err != nil { log.Println(err) } else { defer f.Close() pointsLog := make(award.List, 0, 200) scanner := bufio.NewScanner(f) for scanner.Scan() { line := scanner.Text() cur, err := award.Parse(line) if err != nil { log.Printf("Skipping malformed award line %s: %s", line, err) continue } pointsLog = append(pointsLog, cur) } s.pointsLog = pointsLog } // Only do this if the teams directory has a newer mtime; directories with // hundreds of team names can cause NFS I/O storms { _, ismmfs := s.Fs.(*afero.MemMapFs) // Tests run so quickly that the time check isn't precise enough if fi, err := s.Fs.Stat("teams"); err != nil { log.Printf("Getting modification time of teams directory: %v", err) } else if ismmfs || s.teamsLastChange.Before(fi.ModTime()) { s.teamsLastChange = fi.ModTime() // The compiler recognizes this as an optimization case for k := range s.teams { delete(s.teams, k) } teamsFs := afero.NewBasePathFs(s.Fs, "teams") if dirents, err := afero.ReadDir(teamsFs, "."); err != nil { log.Printf("Reading team ids: %v", err) } else { for _, dirent := range dirents { team := Team{ Name: "", ID: dirent.Name(), } // Dereference links a few times before giving up for i := 0; i < 2; i++ { teamNameBytes, err := afero.ReadFile(teamsFs, team.ID) if err != nil { log.Printf("Reading team %s: %v", team.ID, err) team.Name = err.Error() } team.Name = string(teamNameBytes) if !strings.HasPrefix(team.Name, TeamLinkPrefix) { team.Name = strings.TrimSpace(team.Name) if team.Name == "" { team.Name = "∅" // Empty set } break } team.ID = team.Name[len(TeamLinkPrefix):] team.Name = "[Too Many Links]" } s.teams[team.ID] = team } } } } if bMessages, err := afero.ReadFile(s, "messages.html"); err == nil { s.messages = string(bMessages) } } func (s *State) refresh() { s.maybeInitialize() s.updateEnabled() if s.Enabled { s.collectPoints() } s.updateCaches() } // Maintain performs housekeeping on a State struct. func (s *State) Maintain(updateInterval time.Duration) { ticker := time.NewTicker(updateInterval) s.refresh() for { select { case msg := <-s.eventStream: s.eventWriter.Write(msg) s.eventWriter.Flush() s.eventWriterFile.Sync() case <-ticker.C: s.refresh() case <-s.refreshNow: s.refresh() } } } // DevelState is a StateProvider for use by development servers type DevelState struct { StateProvider } // NewDevelState returns a new state object that can be used by the development server. // // The main thing this provides is the ability to register a team with any team ID. // If a team ID is provided that wasn't recognized by the underlying StateProvider, // it is associated with a team named "". // // This makes it possible to use the server without having to register a team. func NewDevelState(sp StateProvider) *DevelState { return &DevelState{sp} } // TeamName returns a valid team name for any teamID // // If one's registered, it will use it. // Otherwise, it returns "" func (ds *DevelState) TeamName(teamID string) (Team, error) { if team, err := ds.StateProvider.TeamName(teamID); err == nil { return team, nil } team := Team{ Name: fmt.Sprintf("«devel:%s»", teamID), ID: teamID, } return team, nil } // SetTeamName associates a team name with any teamID // // If the underlying StateProvider returns any sort of error, // this returns ErrAlreadyRegistered, // so the user can join a pre-existing team for whatever ID the provide. func (ds *DevelState) SetTeamName(teamID, teamName string) error { if err := ds.StateProvider.SetTeamName(teamID, teamName); err != nil { return ErrAlreadyRegistered } return nil }