moth/cmd/mothd/state.go

327 lines
7.7 KiB
Go

package main
import (
"bufio"
"fmt"
"log"
"math/rand"
"os"
"path/filepath"
"strings"
"time"
"github.com/spf13/afero"
)
// Stuff people with mediocre handwriting could write down unambiguously, and can be entered without holding down shift
const DistinguishableChars = "234678abcdefhikmnpqrtwxyz="
// 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 bool
}
func NewState(fs afero.Fs) *State {
return &State{
Fs: fs,
Enabled: true,
}
}
// Check a few things to see if this state directory is "enabled".
func (s *State) UpdateEnabled() {
if _, err := s.Stat("enabled"); os.IsNotExist(err) {
s.Enabled = false
log.Println("Suspended: enabled file missing")
return
}
nextEnabled := true
untilFile, err := s.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.Println("Misformatted line in hours file")
}
line = strings.TrimSpace(line)
until, err := time.Parse(time.RFC3339, line)
if err != nil {
log.Println("Suspended: Unparseable until date:", 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) {
// XXX: directory traversal
teamFile := filepath.Join("teams", teamID)
teamNameBytes, err := afero.ReadFile(s, 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, teamName string) error {
if f, err := s.Open("teamids.txt"); err != nil {
return fmt.Errorf("Team IDs file does not exist")
} else {
found := false
scanner := bufio.NewScanner(f)
for scanner.Scan() {
if scanner.Text() == teamID {
found = true
break
}
}
f.Close()
if !found {
return fmt.Errorf("Team ID not found in list of valid Team IDs")
}
}
teamFile := filepath.Join("teams", teamID)
err := afero.WriteFile(s, teamFile, []byte(teamName), os.ModeExclusive|0644)
if os.IsExist(err) {
return fmt.Errorf("Team ID is already registered")
}
return err
}
// Retrieve the current points log
func (s *State) PointsLog() []*Award {
f, err := s.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
}
// Retrieve current messages
func (s *State) Messages() string {
bMessages, _ := afero.ReadFile(s, "messages.html")
return string(bMessages)
}
// 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, tmpfn, []byte(a.String()), 0644); err != nil {
return err
}
if err := s.Rename(tmpfn, newfn); err != nil {
return err
}
// XXX: update everything
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
}
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.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.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")
s.Remove("points.log")
s.Remove("messages.html")
s.RemoveAll("points.tmp")
s.RemoveAll("points.new")
s.RemoveAll("teams")
// 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 += 1 {
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 initaliazed at", now)
f.Close()
}
if f, err := s.Create("enabled"); err == nil {
fmt.Fprintln(f, "enabled: remove or rename to suspend the contest.")
f.Close()
}
if f, err := s.Create("hours"); err == nil {
fmt.Fprintln(f, "# hours: when the contest is enabled")
fmt.Fprintln(f, "#")
fmt.Fprintln(f, "# Enable: + timestamp")
fmt.Fprintln(f, "# Disable: - timestamp")
fmt.Fprintln(f, "#")
fmt.Fprintln(f, "# You can have multiple start/stop times.")
fmt.Fprintln(f, "# Whatever time is the most recent, wins.")
fmt.Fprintln(f, "# Times in the future are ignored.")
fmt.Fprintln(f)
fmt.Fprintln(f, "+", now)
fmt.Fprintln(f, "- 3019-10-31T00:00:00Z")
f.Close()
}
if f, err := s.Create("messages.html"); err == nil {
fmt.Fprintln(f, "<!-- messages.html: put client broadcast messages here. -->")
f.Close()
}
if f, err := s.Create("points.log"); err == nil {
f.Close()
}
}
func (s *State) Update() {
s.maybeInitialize()
s.UpdateEnabled()
if s.Enabled {
s.collectPoints()
}
}