moth/cmd/mothd/state.go

373 lines
8.4 KiB
Go

package main
import (
"bufio"
"fmt"
"github.com/spf13/afero"
"log"
"math/rand"
"os"
"path/filepath"
"strconv"
"strings"
"time"
)
// Stuff people with mediocre handwriting could write down unambiguously, and can be entered without holding down shift
const distinguishableChars = "234678abcdefhijkmnpqrtwxyz="
func mktoken() string {
a := make([]byte, 8)
for i := range a {
char := rand.Intn(len(distinguishableChars))
a[i] = distinguishableChars[char]
}
return string(a)
}
type StateExport struct {
TeamNames map[string]string
PointsLog []Award
Messages []string
}
// 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 {
Enabled bool
update chan bool
fs afero.Fs
}
func NewState(fs afero.Fs) *State {
return &State{
Enabled: true,
update: make(chan bool, 10),
fs: fs,
}
}
// Check a few things to see if this state directory is "enabled".
func (s *State) UpdateEnabled() {
if _, err := s.fs.Stat("enabled"); os.IsNotExist(err) {
s.Enabled = false
log.Print("Suspended: enabled file missing")
return
}
nextEnabled := true
untilFile, err := s.fs.Open("hours")
if err != nil {
return
}
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.Printf("Misformatted line in hours file")
}
line = strings.TrimSpace(line)
until, err := time.Parse(time.RFC3339, line)
if err != nil {
log.Printf("Suspended: Unparseable until date: %s", line)
continue
}
if until.Before(time.Now()) {
nextEnabled = thisEnabled
}
}
if nextEnabled != s.Enabled {
s.Enabled = nextEnabled
log.Println("Setting enabled to", s.Enabled, "based on hours file")
}
}
// Returns team name given a team ID.
func (s *State) TeamName(teamId string) (string, error) {
teamFile := filepath.Join("teams", teamId)
teamNameBytes, err := afero.ReadFile(s.fs, teamFile)
teamName := strings.TrimSpace(string(teamNameBytes))
if os.IsNotExist(err) {
return "", fmt.Errorf("Unregistered team ID: %s", teamId)
} else if err != nil {
return "", fmt.Errorf("Unregistered team ID: %s (%s)", teamId, err)
}
return teamName, nil
}
// Write out team name. This can only be done once.
func (s *State) SetTeamName(teamId string, teamName string) error {
teamFile := filepath.Join("teams", teamId)
err := afero.WriteFile(s.fs, teamFile, []byte(teamName), os.ModeExclusive|0644)
return err
}
// Retrieve the current points log
func (s *State) PointsLog() []*Award {
f, err := s.fs.Open("points.log")
if err != nil {
log.Println(err)
return nil
}
defer f.Close()
pointsLog := make([]*Award, 0, 200)
scanner := bufio.NewScanner(f)
for scanner.Scan() {
line := scanner.Text()
cur, err := ParseAward(line)
if err != nil {
log.Printf("Skipping malformed award line %s: %s", line, err)
continue
}
pointsLog = append(pointsLog, cur)
}
return pointsLog
}
// Return an exportable points log,
// This anonymizes teamId with either an integer, or the string "self"
// for the requesting teamId.
func (s *State) Export(teamId string) *StateExport {
teamName, _ := s.TeamName(teamId)
pointsLog := s.PointsLog()
export := StateExport{
PointsLog: make([]Award, len(pointsLog)),
Messages: make([]string, 0, 10),
TeamNames: map[string]string{"self": teamName},
}
// Read in messages
if f, err := s.fs.Open("messages.txt"); err != nil {
log.Print(err)
} else {
defer f.Close()
scanner := bufio.NewScanner(f)
for scanner.Scan() {
message := scanner.Text()
if strings.HasPrefix(message, "#") {
continue
}
export.Messages = append(export.Messages, message)
}
}
// Read in points
exportIds := map[string]string{teamId: "self"}
for logno, award := range pointsLog {
exportAward := award
if id, ok := exportIds[award.TeamId]; ok {
exportAward.TeamId = id
} else {
exportId := strconv.Itoa(logno)
exportAward.TeamId = exportId
exportIds[award.TeamId] = exportAward.TeamId
name, err := s.TeamName(award.TeamId)
if err != nil {
name = "Rodney" // https://en.wikipedia.org/wiki/Rogue_(video_game)#Gameplay
}
export.TeamNames[exportId] = name
}
export.PointsLog[logno] = *exportAward
}
return &export
}
// AwardPoints gives points to teamId in category.
// 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(teamId, category string, points int) error {
a := Award{
When: time.Now().Unix(),
TeamId: teamId,
Category: category,
Points: points,
}
_, err := s.TeamName(teamId)
if err != nil {
return err
}
for _, e := range s.PointsLog() {
if a.Same(e) {
return fmt.Errorf("Points already awarded to this team in this category")
}
}
fn := fmt.Sprintf("%s-%s-%d", teamId, category, points)
tmpfn := filepath.Join("points.tmp", fn)
newfn := filepath.Join("points.new", fn)
if err := afero.WriteFile(s.fs, tmpfn, []byte(a.String()), 0644); err != nil {
return err
}
if err := s.fs.Rename(tmpfn, newfn); err != nil {
return err
}
s.update <- 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.fs, "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.fs, filename)
if err != nil {
log.Print("Opening new points: ", err)
continue
}
award, err := ParseAward(string(awardstr))
if err != nil {
log.Print("Can't parse award file ", filename, ": ", err)
continue
}
duplicate := false
for _, e := range s.PointsLog() {
if award.Same(e) {
duplicate = true
break
}
}
if duplicate {
log.Print("Skipping duplicate points: ", award.String())
} else {
log.Print("Award: ", award.String())
logf, err := s.fs.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, award.String())
logf.Close()
}
if err := s.fs.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.fs.Stat("initialized"); !os.IsNotExist(err) {
return
}
log.Print("initialized file missing, re-initializing")
// Remove any extant control and state files
s.fs.Remove("enabled")
s.fs.Remove("hours")
s.fs.Remove("points.log")
s.fs.Remove("messages.txt")
s.fs.RemoveAll("points.tmp")
s.fs.RemoveAll("points.new")
s.fs.RemoveAll("teams")
// Make sure various subdirectories exist
s.fs.Mkdir("points.tmp", 0755)
s.fs.Mkdir("points.new", 0755)
s.fs.Mkdir("teams", 0755)
// Preseed available team ids if file doesn't exist
if f, err := s.fs.OpenFile("teamids.txt", os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0644); err == nil {
defer f.Close()
for i := 0; i <= 100; i += 1 {
fmt.Fprintln(f, mktoken())
}
}
// Create some files
afero.WriteFile(
s.fs,
"initialized",
[]byte("state/initialized: remove to re-initialize the contest\n"),
0644,
)
afero.WriteFile(
s.fs,
"enabled",
[]byte("state/enabled: remove to suspend the contest\n"),
0644,
)
afero.WriteFile(
s.fs,
"hours",
[]byte(
"# state/hours: when the contest is enabled\n"+
"# Lines starting with + enable, with - disable.\n"+
"\n"+
"+ 1970-01-01T00:00:00Z\n"+
"- 3019-10-31T00:00:00Z\n",
),
0644,
)
afero.WriteFile(
s.fs,
"messages.txt",
[]byte(fmt.Sprintf("[%s] Initialized.\n", time.Now().UTC().Format(time.RFC3339))),
0644,
)
afero.WriteFile(
s.fs,
"points.log",
[]byte(""),
0644,
)
}
func (s *State) Cleanup() {
s.maybeInitialize()
s.UpdateEnabled()
if s.Enabled {
s.collectPoints()
}
}
func (s *State) Run(updateInterval time.Duration) {
for {
s.Cleanup()
select {
case <-s.update:
case <-time.After(updateInterval):
}
}
}