wurgurboo: convert into systemd service with short links

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

README.md

@@ -28,3 +28,11 @@ This is best used with `+z` in a channel. It responds to all messages with a sta
 ```go
 go get golang.zx2c4.com/irc/cmd/irc-simple-responder
 ```
+
+### `wurgurboo` - the "WurGurBoo" bot for `#wireguard`
+
+This polls for commits and does various things in the `#wireguard` channel. It's meant to be run as a [`go-web-service`](https://git.zx2c4.com/go-web-services/).
+
+```go
+go get golang.zx2c4.com/irc/cmd/wurgurboo
+```

cmd/wurgurboo/main.go

@@ -6,56 +6,32 @@
 package main
 
 import (
-	"bufio"
-	"flag"
 	"fmt"
 	"log"
 	"net"
+	"net/http"
 	"os"
-	"regexp"
+	"os/signal"
+	"path/filepath"
+	"syscall"
 	"time"
 
 	"golang.zx2c4.com/irc/hbot"
 )
 
 func main() {
-	channelArg := flag.String("channel", "", "channel to join")
-	serverArg := flag.String("server", "", "server and port")
-	nickArg := flag.String("nick", "", "nickname")
-	passwordArg := flag.String("password-file", "", "optional file with password")
-	flag.Parse()
-	if matched, _ := regexp.MatchString(`^#[a-zA-Z0-9_-]+$`, *channelArg); !matched {
-		fmt.Fprintln(os.Stderr, "Invalid channel")
-		flag.Usage()
-		os.Exit(1)
-	}
-	if _, _, err := net.SplitHostPort(*serverArg); err != nil {
-		fmt.Fprintln(os.Stderr, "Invalid server")
-		flag.Usage()
-		os.Exit(1)
-	}
-	if matched, _ := regexp.MatchString(`^[a-zA-Z0-9\[\]_-]{1,16}$`, *nickArg); !matched {
-		fmt.Fprintln(os.Stderr, "Invalid nick")
-		flag.Usage()
-		os.Exit(1)
-	}
-	password := ""
-	if len(*passwordArg) > 0 {
-		f, err := os.Open(*passwordArg)
+	shortlink := NewShortLink(filepath.Join(os.Getenv("STATE_DIRECTORY"), "links.txt"))
+	http.HandleFunc("/l/", shortlink.HandleRequest)
+	listener, err := net.FileListener(os.Stdin)
 	if err != nil {
-			fmt.Fprintf(os.Stderr, "Unable to open password file: %v\n", err)
-			os.Exit(1)
+		log.Fatal(err)
 	}
-		password, err = bufio.NewReader(f).ReadString('\n')
-		f.Close()
+	go func() {
+		err = http.Serve(listener, nil)
 		if err != nil {
-			fmt.Fprintf(os.Stderr, "Unable to read password file: %v\n", err)
-			os.Exit(1)
-		}
-		if len(password) > 0 && password[len(password)-1] == '\n' {
-			password = password[:len(password)-1]
-		}
+			log.Fatal(err)
 		}
+	}()
 
 	feeds := NewCgitFeedMonitorer(time.Second * 10)
 	feeds.AddFeed("https://git.zx2c4.com/wireguard-linux/")
@@ -72,25 +48,48 @@ func main() {
 	feeds.AddFeed("https://git.zx2c4.com/wintun/")
 	feeds.AddFeed("https://git.zx2c4.com/wg-dynamic/")
 
+	const channel = "#wireguard"
 	bot := hbot.NewBot(&hbot.Config{
-		Host:     *serverArg,
-		Nick:     *nickArg,
+		Host:     "irc.libera.chat:6697",
+		Nick:     "WurGurBoo",
 		Realname: "Your Friendly Neighborhood WurGur Bot",
-		Channels: []string{*channelArg},
+		Channels: []string{channel},
 		Logger:   hbot.Logger{Verbosef: log.Printf, Errorf: log.Printf},
-		Password: password,
+		Password: os.Getenv("WURGURBOO_PASSWORD"),
 	})
 
-	urlShortener := regexp.MustCompile(`(.*\?id=[a-f0-9]{8})([a-f0-9]+)$`)
+	c := make(chan os.Signal, 1)
+	signal.Notify(c, syscall.SIGINT, syscall.SIGTERM)
+	go func() {
+		for range c {
+			bot.Close()
+			shortlink.SaveToDisk()
+			os.Exit(0)
+		}
+	}()
+
+	type seenCommit struct {
+		repo    string
+		subject string
+	}
+	seenCommits := make(map[seenCommit]string, 4096)
+
 	go func() {
 		for commit := range feeds.Updates() {
 			<-bot.Joined()
-			log.Printf("New commit %s in %s", commit.Commit.ID, commit.RepoTitle)
-			url := commit.Commit.Link.Href
-			if matches := urlShortener.FindStringSubmatch(url); len(matches) == 3 {
-				url = matches[1]
+			sc := seenCommit{commit.RepoTitle, commit.Commit.Title}
+			if short, ok := seenCommits[sc]; ok {
+				log.Printf("Updated commit %s in %s", commit.Commit.ID, commit.RepoTitle)
+				shortlink.Set(short, commit.Commit.Link.Href, true)
+				continue
 			}
-			bot.Msg(*channelArg, fmt.Sprintf("\x01ACTION found a new commit in \x0303%s\x0f - \x0306%s\x0f - %s\x01", commit.RepoTitle, commit.Commit.Title, url))
+			log.Printf("New commit %s in %s", commit.Commit.ID, commit.RepoTitle)
+			short := shortlink.New(commit.Commit.Link.Href)
+			seenCommits[sc] = short
+			bot.Msg(channel, fmt.Sprintf("\x01ACTION found a new commit in \x0303%s\x0f - \x0306%s\x0f - %s\x01",
+				sc.repo, sc.subject,
+				fmt.Sprintf("https://w-g.pw/l/%s", short)),
+			)
 		}
 	}()
 

cmd/wurgurboo/shortlink.go

@@ -0,0 +1,120 @@
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * Copyright (C) 2021 Jason A. Donenfeld. All Rights Reserved.
+ */
+
+package main
+
+import (
+	"bufio"
+	"crypto/rand"
+	"encoding/base64"
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+	"path"
+	"strings"
+	"sync"
+	"time"
+)
+
+type ShortLink struct {
+	mu            sync.RWMutex
+	diskCachePath string
+	links         map[string]string
+	dirty         bool
+	cacher        *time.Timer
+}
+
+func NewShortLink(diskCachePath string) *ShortLink {
+	sl := &ShortLink{
+		diskCachePath: diskCachePath,
+		links:         make(map[string]string, 4096),
+	}
+	f, err := os.Open(sl.diskCachePath)
+	if err == nil {
+		defer f.Close()
+		scanner := bufio.NewScanner(f)
+		for scanner.Scan() {
+			parts := strings.SplitN(scanner.Text(), "\t", 2)
+			if len(parts) != 2 || len(parts[0]) == 0 || len(parts[1]) == 0 {
+				continue
+			}
+			sl.links[parts[0]] = parts[1]
+		}
+	}
+	return sl
+}
+
+func (sl *ShortLink) Set(k, v string, overwrite bool) bool {
+	sl.mu.Lock()
+	defer sl.mu.Unlock()
+	if wantV, ok := sl.links[k]; ok && (!overwrite || wantV == v) {
+		return false
+	}
+	sl.links[k] = v
+	if !sl.dirty {
+		sl.dirty = true
+		time.AfterFunc(time.Second*10, sl.SaveToDisk)
+	}
+	return true
+}
+
+func (sl *ShortLink) New(v string) string {
+	for {
+		var bytes [3]byte
+		_, err := rand.Read(bytes[:])
+		if err != nil {
+			log.Panicf("RNG is broken: %v", err)
+		}
+		k := base64.RawURLEncoding.EncodeToString(bytes[:])
+		sl.mu.RLock()
+		_, exists := sl.links[k]
+		sl.mu.RUnlock()
+		if !exists && sl.Set(k, v, false) {
+			return k
+		}
+	}
+}
+
+func (sl *ShortLink) HandleRequest(w http.ResponseWriter, r *http.Request) {
+	w.Header().Add("Server", "WurGurBoo/1.0")
+	target := "https://www.wireguard.com/"
+	wantL, key := path.Split(r.URL.Path)
+	if wantL == "/l/" {
+		sl.mu.RLock()
+		v, ok := sl.links[key]
+		sl.mu.RUnlock()
+		if ok {
+			target = v
+		}
+	}
+	http.Redirect(w, r, target, 302)
+}
+
+func (sl *ShortLink) SaveToDisk() {
+	sl.mu.Lock()
+	dirty := sl.dirty
+	sl.dirty = false
+	sl.mu.Unlock()
+	if !dirty {
+		return
+	}
+	f, err := os.Create(sl.diskCachePath + ".tmp")
+	if err != nil {
+		log.Printf("Unable to backup short link db: %v", err)
+		return
+	}
+	defer f.Close()
+	sl.mu.RLock()
+	for k, v := range sl.links {
+		fmt.Fprintf(f, "%s\t%s\n", k, v)
+	}
+	sl.mu.RUnlock()
+	err = os.Rename(f.Name(), sl.diskCachePath)
+	if err != nil {
+		log.Printf("Unable to backup short link db: %v", err)
+		return
+	}
+}