Yet More Plumbing for multi-host setup.

- Move peers from flags to args in the app
- Allow users to specify peers as IPs and hostname, both with and without ports
- Allos users to specify peers on ./scope launch, and plumb that through entrypoint.sh and run-app

app/main.go

@@ -10,7 +10,6 @@ import (
 	"os"
 	"os/signal"
 	"strconv"
-	"strings"
 	"syscall"
 	"time"
 
@@ -24,12 +23,12 @@ func main() {
 	var (
 		defaultProbes = []string{fmt.Sprintf("localhost:%d", xfer.ProbePort), fmt.Sprintf("scope.weave.local:%d", xfer.ProbePort)}
 		logfile       = flag.String("log", "stderr", "stderr, syslog, or filename")
-		probes        = flag.String("probes", strings.Join(defaultProbes, ","), "list of probe endpoints, comma separated")
 		batch         = flag.Duration("batch", 1*time.Second, "batch interval")
 		window        = flag.Duration("window", 15*time.Second, "window")
 		listen        = flag.String("http.address", ":"+strconv.Itoa(xfer.AppPort), "webserver listen address")
 	)
 	flag.Parse()
+	probes := append(defaultProbes, flag.Args()...)
 
 	switch *logfile {
 	case "stderr":
@@ -62,7 +61,7 @@ func main() {
 	c := xfer.NewCollector(*batch)
 	defer c.Stop()
 
-	r := NewResolver(strings.Split(*probes, ","), c.AddAddress)
+	r := NewResolver(probes, c.AddAddress)
 	defer r.Stop()
 
 	lifo := NewReportLIFO(c, *window)

app/resolver.go

@@ -3,7 +3,11 @@ package main
 import (
 	"log"
 	"net"
+	"strconv"
+	"strings"
 	"time"
+
+	"github.com/weaveworks/scope/xfer"
 )
 
 var (
@@ -42,11 +46,22 @@ func NewResolver(peers []string, add func(string)) Resolver {
 func prepareNames(strs []string) []peer {
 	var results []peer
 	for _, s := range strs {
-		hostname, port, err := net.SplitHostPort(s)
-		if err != nil {
-			log.Printf("invalid address %s: %v", s, err)
-			continue
+		var (
+			hostname string
+			port     string
+			err      error
+		)
+
+		if strings.Contains(s, ":") {
+			hostname, port, err = net.SplitHostPort(s)
+			if err != nil {
+				log.Printf("invalid address %s: %v", s, err)
+				continue
+			}
+		} else {
+			hostname, port = s, strconv.Itoa(xfer.ProbePort)
 		}
+
 		results = append(results, peer{hostname, port})
 	}
 	return results
@@ -67,10 +82,19 @@ func (r Resolver) loop() {
 
 func (r Resolver) resolveHosts() {
 	for _, peer := range r.peers {
-		addrs, err := lookupIP(peer.hostname)
-		if err != nil {
-			log.Printf("lookup %s: %v", peer.hostname, err)
-			continue
+		var (
+			addrs []net.IP
+			err   error
+		)
+
+		if addr := net.ParseIP(peer.hostname); addr != nil {
+			addrs = []net.IP{addr}
+		} else {
+			addrs, err = lookupIP(peer.hostname)
+			if err != nil {
+				log.Printf("lookup %s: %v", peer.hostname, err)
+				continue
+			}
 		}
 
 		for _, addr := range addrs {

docker/entrypoint.sh

@@ -31,4 +31,12 @@ if [ -n "$DNS_SERVER" -a -n "$SEARCHPATH" ]; then
     echo "nameserver $DNS_SERVER" >>/etc/resolv.conf
 fi
 
+# End of the command line can optionally be some
+# addresses of probes to connect to, for people not
+# using Weave DNS.  We stick these in /etc/weave/probes
+# for the run-app script to pick up.
+MANUAL_PROBES=$@
+mkdir -p /etc/weave
+echo "$MANUAL_PROBES" >/etc/weave/probes
+
 exec /sbin/runsvdir /etc/service

docker/run-app

@@ -1,3 +1,3 @@
 #!/bin/sh
 
-exec /home/weave/app
+exec /home/weave/app $(cat /etc/weave/probes)

scope

@@ -118,7 +118,6 @@ container_ip() {
 case "$COMMAND" in
 
 	launch)
-		[ $# -eq 0 ] || usage
 		check_not_running $CONTAINER_NAME $IMAGE
 
 		# If WeaveDNS is running, we want to automatically tell the scope