1 files changed, 305 insertions, 0 deletions
diff --git a/fun/clbot/clbot.go b/fun/clbot/clbot.go
new file mode 100644
index 000000000000..40b044f45d39
--- /dev/null
+++ b/fun/clbot/clbot.go
@@ -0,0 +1,305 @@
+package main
+
+import (
+	"context"
+	"crypto/tls"
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"net"
+	"os"
+	"os/signal"
+	"strings"
+	"time"
+
+	"code.tvl.fyi/fun/clbot/backoffutil"
+	"code.tvl.fyi/fun/clbot/gerrit"
+	"code.tvl.fyi/fun/clbot/gerrit/gerritevents"
+	log "github.com/golang/glog"
+	"golang.org/x/crypto/ssh"
+	"gopkg.in/irc.v3"
+)
+
+var (
+	gerritAddr       = flag.String("gerrit_host", "cl.tvl.fyi:29418", "Gerrit SSH host:port")
+	gerritSSHHostKey = flag.String("gerrit_ssh_pubkey", "ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBIUNYBYPCCBNDFSd0BuCR+8kgeuJ7IA5S2nTNQmkQUYNyXK+ot5os7rHtCk96+grd5+J8jFCuFBWisUe8h8NC0Q=", "Gerrit SSH public key")
+	gerritSSHTimeout = flag.Duration("gerrit_tcp_timeout", 5*time.Second, "Gerrit SSH TCP connect timeout")
+
+	gerritAuthUsername = flag.String("gerrit_ssh_auth_username", "", "Gerrit SSH username")
+	gerritAuthKeyPath  = flag.String("gerrit_ssh_auth_key", "", "Gerrit SSH private key path")
+
+	ircServer    = flag.String("irc_server", "irc.hackint.org:6697", "IRC server to connect to")
+	ircTls       = flag.Bool("irc_tls", false, "Does the server connection need TLS?")
+	ircNick      = flag.String("irc_nick", "clbot", "Nick to use when connecting to IRC")
+	ircUser      = flag.String("irc_user", "clbot", "User string to use for IRC")
+	ircName      = flag.String("irc_name", "clbot", "Name string to use for IRC")
+	ircChannel   = flag.String("irc_channel", "#tvl", "Channel to send messages to")
+	ircPassword  = flag.String("irc_pass", "", "Password to use for IRC")
+	ircSendLimit = flag.Duration("irc_send_limit", 100*time.Millisecond, "Delay between messages")
+	ircSendBurst = flag.Int("irc_send_burst", 10, "Number of messages which can be sent in a burst")
+
+	notifyRepo     = flag.String("notify_repo", "depot", "Repo name to notify about")
+	notifyBranches = stringSetFlag{}
+
+	neverPing   = flag.String("never_ping", "marcus", "Comma-separated terms that should never ping users")
+	onlyDisplay = flag.String("only_display", "", "Comma-separated substrings of the gerrit CL Change Subject that should be shown (everything else is dropped)")
+)
+
+func init() {
+	flag.Var(&notifyBranches, "notify_branches", "Branch names (comma-separated, or repeated flags, or both) to notify users about")
+}
+
+type stringSetFlag map[string]bool
+
+func (f stringSetFlag) String() string {
+	return fmt.Sprintf("%v", map[string]bool(f))
+}
+func (f stringSetFlag) Set(s string) error {
+	if s == "" {
+		return nil
+	}
+	for _, k := range strings.Split(s, ",") {
+		if k != "" {
+			f[k] = true
+		}
+	}
+	return nil
+}
+
+func mustFixedHostKey(f string) ssh.HostKeyCallback {
+	pk, _, _, _, err := ssh.ParseAuthorizedKey([]byte(f))
+	if err != nil {
+		log.Exitf("ParseAuthorizedKey(%q): %v", f, err)
+	}
+	return ssh.FixedHostKey(pk)
+}
+
+func mustPrivateKey(p string) ssh.AuthMethod {
+	pkBytes, err := ioutil.ReadFile(p)
+	if err != nil {
+		log.Exitf("reading SSH private key from %q: %v", p, err)
+	}
+	pk, err := ssh.ParsePrivateKey(pkBytes)
+	if err != nil {
+		log.Exitf("parsing private key from %q: %v", p, err)
+	}
+	return ssh.PublicKeys(pk)
+}
+
+var shutdownFuncs []func()
+
+func callOnShutdown(f func()) {
+	shutdownFuncs = append(shutdownFuncs, f)
+}
+
+// Unicode U+200B zero-width-space, to avoid triggering other bots
+// or highlighting people on IRC.
+const zeroWidthSpace = "\u200b"
+
+func runIRC(ctx context.Context, ircCfg irc.ClientConfig, sendMsg <-chan string) {
+	bo := backoffutil.NewDefaultBackOff()
+	ircCfg.Handler = irc.HandlerFunc(func(c *irc.Client, m *irc.Message) {
+		if m.Command == "NOTICE" && m.Prefix.Name == "NickServ" && strings.Contains(m.Trailing(), "dentified") {
+			// We're probably identified now, go join the channel.
+			c.Writef("JOIN %s", *ircChannel)
+		}
+	})
+	for {
+		timer := time.NewTimer(bo.NextBackOff())
+		select {
+		case <-ctx.Done():
+			timer.Stop()
+			return
+		case <-timer.C:
+			break
+		}
+
+		(func() {
+			connectedStart := time.Now()
+
+			var ircConn net.Conn
+			var err error
+
+			if *ircTls {
+				ircConn, err = tls.Dial("tcp", *ircServer, nil)
+			} else {
+				ircConn, err = net.Dial("tcp", *ircServer)
+			}
+
+			if err != nil {
+				log.Errorf("connecting to IRC at tcp/%s (tls: %v): %v", *ircServer, *ircTls, err)
+				return
+			}
+
+			ircClient := irc.NewClient(ircConn, ircCfg)
+			ircClientCtx, cancel := context.WithCancel(ctx)
+			defer cancel()
+			go func() {
+				for {
+					select {
+					case <-ircClientCtx.Done():
+						return
+					case msg := <-sendMsg:
+						log.Infof("sending message %q to %v", msg, *ircChannel)
+						ircClient.Writef("PRIVMSG %s :%s%s", *ircChannel, zeroWidthSpace, msg)
+					}
+				}
+			}()
+			log.Infof("connecting to IRC on tcp/%s", *ircServer)
+			if err := ircClient.RunContext(ircClientCtx); err != nil {
+				connectedEnd := time.Now()
+				connectedFor := connectedEnd.Sub(connectedStart)
+				if connectedFor > 60*time.Second {
+					bo.Reset()
+				}
+				log.Errorf("IRC RunContext: %v", err)
+				return
+			}
+		})()
+	}
+}
+
+func username(a gerritevents.Account) string {
+	options := []string{
+		a.Username,
+		a.Name,
+		a.Email,
+	}
+	for _, opt := range options {
+		if opt != "" {
+			return opt
+		}
+	}
+	return "UNKNOWN USER"
+}
+
+// noping inserts a Unicode zero-width space between the first and rest characters of `user`
+// in an effort to avoid pinging that user on IRC.
+func noping(user string) string {
+	un := []rune(user)
+	return string(un[0:1]) + zeroWidthSpace + string(un[1:])
+}
+
+// Apply noping to each instance of the username in the supplied
+// message. With this users will not be pinged for their own CLs, but
+// they will be notified if someone else writes a CL that includes
+// their username.
+//
+// Also applies noping to all instances of the words in `neverPing`.
+func nopingAll(username, message string) string {
+	for _, word := range strings.Split(*neverPing, ",") {
+		message = strings.ReplaceAll(message, word, noping(word))
+	}
+
+	return strings.ReplaceAll(message, username, noping(username))
+}
+
+// changeShouldBeSkipped applies the list of channels in `onlyDisplay`
+// to whether we should skip displaying a CL.
+func changeShouldBeSkipped(onlyDisplay string, changeSubject string) bool {
+	// case when we don’t want to filter
+	if onlyDisplay == "" {
+		return false
+	}
+	for _, needle := range strings.Split(onlyDisplay, ",") {
+		if strings.Contains(changeSubject, needle) {
+			return false
+		}
+	}
+	return true
+}
+
+func patchSetURL(c gerritevents.Change, p gerritevents.PatchSet) string {
+	return fmt.Sprintf("https://cl.tvl.fyi/%d", c.Number)
+}
+
+func main() {
+	flag.Parse()
+	failed := false
+	if *gerritAuthUsername == "" {
+		log.Errorf("gerrit_ssh_auth_username must be set")
+		failed = true
+	}
+	if *gerritAuthKeyPath == "" {
+		log.Errorf("gerrit_ssh_auth_key must be set")
+		failed = true
+	}
+	if failed {
+		os.Exit(2)
+	}
+
+	shutdownCh := make(chan os.Signal)
+	signal.Notify(shutdownCh, os.Interrupt)
+	go func() {
+		<-shutdownCh
+		signal.Reset(os.Interrupt)
+		for n := len(shutdownFuncs) - 1; n >= 0; n-- {
+			shutdownFuncs[n]()
+		}
+	}()
+
+	ctx, cancel := context.WithCancel(context.Background())
+	callOnShutdown(cancel)
+	cfg := &ssh.ClientConfig{
+		User:            *gerritAuthUsername,
+		Auth:            []ssh.AuthMethod{mustPrivateKey(*gerritAuthKeyPath)},
+		HostKeyCallback: mustFixedHostKey(*gerritSSHHostKey),
+		Timeout:         *gerritSSHTimeout,
+	}
+	cfg.SetDefaults()
+
+	gw, err := gerrit.New(ctx, "tcp", *gerritAddr, cfg)
+	if err != nil {
+		log.Exitf("gerrit.New(%q): %v", *gerritAddr, err)
+	}
+	callOnShutdown(func() {
+		ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
+		defer cancel()
+		gw.Close(ctx)
+	})
+
+	sendMsgChan := make(chan string, 5)
+	go func() {
+		for e := range gw.Events() {
+			var parsedMsg string
+			switch e := e.(type) {
+			case *gerritevents.PatchSetCreated:
+				if e.Change.Project != *notifyRepo || !notifyBranches[e.Change.Branch] || e.PatchSet.Number != 1 || changeShouldBeSkipped(*onlyDisplay, e.Change.Subject) {
+					continue
+				}
+				user := username(e.PatchSet.Uploader)
+				parsedMsg = nopingAll(user, fmt.Sprintf("CL/%d proposed by %s - %s - %s", e.Change.Number, user, e.Change.Subject, patchSetURL(e.Change, e.PatchSet)))
+			case *gerritevents.ChangeMerged:
+				if e.Change.Project != *notifyRepo || !notifyBranches[e.Change.Branch] || changeShouldBeSkipped(*onlyDisplay, e.Change.Subject) {
+					continue
+				}
+				owner := username(e.Change.Owner)
+				submitter := e.Submitter.Username
+				url := patchSetURL(e.Change, e.PatchSet)
+
+				if submitter != owner && submitter == "clbot" {
+					parsedMsg = nopingAll(owner, fmt.Sprintf("CL/%d by %s autosubmitted - %s - %s", e.Change.Number, owner, e.Change.Subject, url))
+				} else {
+					parsedMsg = nopingAll(owner, fmt.Sprintf("CL/%d applied by %s - %s - %s", e.Change.Number, owner, e.Change.Subject, url))
+				}
+			}
+			if parsedMsg != "" {
+				sendMsgChan <- parsedMsg
+			}
+		}
+	}()
+
+	ircCtx, ircCancel := context.WithCancel(ctx)
+	callOnShutdown(ircCancel)
+	go runIRC(ircCtx, irc.ClientConfig{
+		Nick: *ircNick,
+		User: *ircUser,
+		Name: *ircName,
+		Pass: *ircPassword,
+
+		SendLimit: *ircSendLimit,
+		SendBurst: *ircSendBurst,
+	}, sendMsgChan)
+
+	<-ctx.Done()
+}