feat(clbot): Add IRC support to the IRC bot. r/990

Change-Id: I183488824882750c46e7216b98ab48e1d8f48096
Reviewed-on: https://cl.tvl.fyi/c/depot/+/343
Reviewed-by: eta <eta@theta.eu.org>
Reviewed-by: tazjin <mail@tazj.in>

4 files changed, 158 insertions, 26 deletions

diff --git a/fun/clbot/clbot.go b/fun/clbot/clbot.go
index 7fa12f2c3b..b7bfa0d961 100644
--- a/fun/clbot/clbot.go
+++ b/fun/clbot/clbot.go
@@ -2,16 +2,21 @@ package main
 
 import (
 	"context"
+	"crypto/tls"
 	"flag"
+	"fmt"
 	"io/ioutil"
 	"os"
 	"os/signal"
+	"strings"
 	"time"
 
+	"code.tvl.fyi/fun/clbot/backoffutil"
 	"code.tvl.fyi/fun/clbot/gerrit"
-	"github.com/davecgh/go-spew/spew"
+	"code.tvl.fyi/fun/clbot/gerrit/gerritevents"
 	log "github.com/golang/glog"
 	"golang.org/x/crypto/ssh"
+	"gopkg.in/irc.v3"
 )
 
 var (
@@ -19,9 +24,17 @@ var (
 	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")
 
-	required           = flag.NewFlagSet("required flags", flag.ExitOnError)
-	gerritAuthUsername = required.String("gerrit_ssh_auth_username", "", "Gerrit SSH username")
-	gerritAuthKeyPath  = required.String("gerrit_ssh_auth_key", "", "Gerrit SSH private key path")
+	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", "chat.freenode.net:7000", "IRC server to connect to")
+	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")
 )
 
 func mustFixedHostKey(f string) ssh.HostKeyCallback {
@@ -44,33 +57,106 @@ func mustPrivateKey(p string) ssh.AuthMethod {
 	return ssh.PublicKeys(pk)
 }
 
-func checkRequired(fs *flag.FlagSet) {
-	missing := map[string]bool{}
-	fs.VisitAll(func(f *flag.Flag) { missing[f.Name] = true })
-	fs.Visit(func(f *flag.Flag) { delete(missing, f.Name) })
-	for f := range missing {
-		log.Errorf("flag %q was unset but is required", f)
-	}
-	if len(missing) > 0 {
-		os.Exit(1)
-	}
-}
-
 var shutdownFuncs []func()
 
 func callOnShutdown(f func()) {
 	shutdownFuncs = append(shutdownFuncs, f)
 }
 
+const ignoreBotChar = "\xe2\x80\x8b"
+
+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()
+			ircConn, err := tls.Dial("tcp", *ircServer, nil)
+			if err != nil {
+				log.Errorf("connecting to IRC at tcp/%s: %v", *ircServer, 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, ignoreBotChar, 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(p gerritevents.PatchSet) string {
+	options := []string{
+		p.Uploader.Username,
+		p.Uploader.Name,
+		p.Uploader.Email,
+	}
+	for _, opt := range options {
+		if opt != "" {
+			return opt
+		}
+	}
+	return "UNKNOWN USER"
+}
+
+func patchSetURL(c gerritevents.Change, p gerritevents.PatchSet) string {
+	return fmt.Sprintf("https://cl.tvl.fyi/%d", c.Number)
+}
+
 func main() {
 	flag.Parse()
-	checkRequired(required)
+	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
-		for n := len(shutdownFuncs); n >= 0; n-- {
+		signal.Reset(os.Interrupt)
+		for n := len(shutdownFuncs) - 1; n >= 0; n-- {
 			shutdownFuncs[n]()
 		}
 	}()
@@ -87,15 +173,47 @@ func main() {
 
 	gw, err := gerrit.New(ctx, "tcp", *gerritAddr, cfg)
 	if err != nil {
-		log.Errorf("gerrit.New(%q): %v", *gerritAddr, err)
+		log.Exitf("gerrit.New(%q): %v", *gerritAddr, err)
 	}
 	callOnShutdown(func() {
-		ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+		ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
 		defer cancel()
 		gw.Close(ctx)
 	})
 
-	for e := range gw.Events() {
-		log.Infof("hello: %v", spew.Sdump(e))
-	}
+	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 != "depot" || e.Change.Branch != "master" || e.PatchSet.Number != 1 {
+					continue
+				}
+				parsedMsg = fmt.Sprintf("CL/%d: %q proposed by %s - %s", e.Change.Number, e.Change.Subject, username(e.PatchSet), patchSetURL(e.Change, e.PatchSet))
+			case *gerritevents.ChangeMerged:
+				if e.Change.Project != "depot" || e.Change.Branch != "master" {
+					continue
+				}
+				parsedMsg = fmt.Sprintf("CL/%d: %q submitted by %s - %s", e.Change.Number, e.Change.Subject, username(e.PatchSet), patchSetURL(e.Change, e.PatchSet))
+			}
+			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()
 }
diff --git a/fun/clbot/default.nix b/fun/clbot/default.nix
index 7a255f027a..e6b9c2fb9b 100644
--- a/fun/clbot/default.nix
+++ b/fun/clbot/default.nix
@@ -14,5 +14,6 @@ depot.nix.buildGo.program {
     gopkgs."github.com".davecgh.go-spew.spew.gopkg
     gopkgs."github.com".golang.glog.gopkg
     gopkgs."golang.org".x.crypto.ssh.gopkg
+    gopkgs."gopkg.in"."irc.v3".gopkg
   ];
 }
diff --git a/fun/clbot/go.mod b/fun/clbot/go.mod
index f954c752cb..f1e366ba9d 100644
--- a/fun/clbot/go.mod
+++ b/fun/clbot/go.mod
@@ -4,8 +4,9 @@ go 1.14
 
 require (
 	github.com/cenkalti/backoff/v4 v4.0.2
-	github.com/davecgh/go-spew v1.1.1
+	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b
 	github.com/google/go-cmp v0.4.1
 	golang.org/x/crypto v0.0.0-20200604202706-70a84ac30bf9
+	gopkg.in/irc.v3 v3.1.3
 )
diff --git a/fun/clbot/go.sum b/fun/clbot/go.sum
index 0c7fb33cb9..d5434526e8 100644
--- a/fun/clbot/go.sum
+++ b/fun/clbot/go.sum
@@ -1,13 +1,17 @@
-github.com/cenkalti/backoff v1.1.0 h1:QnvVp8ikKCDWOsFheytRCoYWYPO/ObCTBGxT19Hc+yE=
-github.com/cenkalti/backoff v2.2.1+incompatible h1:tNowT99t7UNflLxfYYSlKYsBpXdEet03Pg2g16Swow4=
 github.com/cenkalti/backoff/v4 v4.0.2 h1:JIufpQLbh4DkbQoii76ItQIUFzevQSqOLZca4eamEDs=
 github.com/cenkalti/backoff/v4 v4.0.2/go.mod h1:eEew/i+1Q6OrCDZh3WiXYv3+nJwBASZ8Bog/87DQnVg=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b h1:VKtxabqXZkF25pY9ekfRL6a582T4P37/31XEstQ5p58=
 github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b/go.mod h1:SBH7ygxi8pfUlaOkMMuAQtPIUF8ecWP5IEl/CR7VP2Q=
 github.com/google/go-cmp v0.4.1 h1:/exdXoGamhu5ONeUJH0deniYLWYvQwW66yvlfiiKTu0=
 github.com/google/go-cmp v0.4.1/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.4.0 h1:2E4SXV/wtOkTonXsotYi4li6zVWxYlZuYNCXe9XRJyk=
+github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20200604202706-70a84ac30bf9 h1:vEg9joUBmeBcK9iSJftGNf3coIG4HqZElCPehJsfAYM=
 golang.org/x/crypto v0.0.0-20200604202706-70a84ac30bf9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
@@ -16,4 +20,12 @@ golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5h
 golang.org/x/sys v0.0.0-20190412213103-97732733099d h1:+R4KGOnez64A81RvjARKc4UT5/tI9ujCIVX+P5KiHuI=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/irc.v3 v3.1.3 h1:yeTiJ365882L8h4AnBKYfesD92y5R5ZhGiylu9DfcPY=
+gopkg.in/irc.v3 v3.1.3/go.mod h1:shO2gz8+PVeS+4E6GAny88Z0YVVQSxQghdrMVGQsR9s=
+gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.2.8 h1:obN1ZagJSUGI0Ek/LBmuj4SNLPfIny3KsKFopxRdj10=
+gopkg.in/yaml.v2 v2.2.8/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=