Move initial DNS population into Go code

prog/weaver/main.go

@@ -384,6 +384,9 @@ func main() {
 		ns.Start()
 		defer ns.Stop()
 		dnsserver.ActivateAndServe()
+		if dockerCli != nil {
+			populateDNS(ns, dockerCli, name, bridgeConfig.WeaveBridgeName)
+		}
 		defer dnsserver.Stop()
 	}
 

prog/weaver/reclaim.go

@@ -2,13 +2,16 @@ package main
 
 import (
 	"net"
+	"strings"
 
 	docker "github.com/fsouza/go-dockerclient"
 
+	"github.com/weaveworks/mesh"
 	"github.com/weaveworks/weave/api"
 	"github.com/weaveworks/weave/common"
 	weavedocker "github.com/weaveworks/weave/common/docker"
 	"github.com/weaveworks/weave/ipam"
+	"github.com/weaveworks/weave/nameserver"
 	weavenet "github.com/weaveworks/weave/net"
 	"github.com/weaveworks/weave/net/address"
 )
@@ -87,3 +90,49 @@ func findExistingAddresses(dockerCli *weavedocker.Client, bridgeName string) (ad
 	}
 	return addrs, nil
 }
+
+func populateDNS(ns *nameserver.Nameserver, dockerCli *weavedocker.Client, ourName mesh.PeerName, bridgeName string) (addrs []ipam.PreClaim, err error) {
+	// Find all veths connected to the bridge
+	peerIDs, err := weavenet.ConnectedToBridgeVethPeerIds(bridgeName)
+	if err != nil {
+		return nil, err
+	}
+
+	// Now iterate over all containers to see if they have a network
+	// namespace with an attached interface
+	if dockerCli != nil {
+		containerIDs, err := dockerCli.RunningContainerIDs()
+		if err != nil {
+			return nil, err
+		}
+
+		for _, cid := range containerIDs {
+			container, err := dockerCli.InspectContainer(cid)
+			if err != nil {
+				if _, ok := err.(*docker.NoSuchContainer); ok {
+					continue
+				}
+				return nil, err
+			}
+			if container.State.Pid != 0 {
+				// Docker allows containers to have fqdns in two wauys:
+				// where the container explicitly has a domain name, and when its
+				// hostname contains the domain name, recognized by it having dots.
+				if container.Config.Domainname == "" && !strings.Contains(container.Config.Hostname, ".") {
+					continue
+				}
+				netDevs, err := weavenet.GetNetDevsByVethPeerIds(container.State.Pid, peerIDs)
+				if err != nil {
+					return nil, err
+				}
+				fqdn := container.Config.Hostname + "." + container.Config.Domainname
+				for _, netDev := range netDevs {
+					for _, cidr := range netDev.CIDRs {
+						ns.AddEntryFQDN(fqdn, cid, ourName, address.FromIP4(cidr.IP))
+					}
+				}
+			}
+		}
+	}
+	return addrs, nil
+}

weave

@@ -1417,7 +1417,6 @@ launch_router() {
         "$@")
     wait_for_status $CONTAINER_NAME http_call $HTTP_ADDR
     setup_awsvpc
-    populate_router
 
     if [ -n "$ENABLE_PLUGIN" ]; then
         wait_for_status $CONTAINER_NAME http_call_unix $CONTAINER_NAME plugin-status.sock
@@ -1437,17 +1436,6 @@ fetch_router_args() {
     NO_DNS_OPT=$(echo $CONTAINER_ARGS | grep -o -e '--no-dns') || true
 }
 
-populate_dns_for_one_container() {
-    [ -z "$4" ] || with_container_fqdn $1 put_dns_fqdn $4
-}
-
-populate_router() {
-    if [ -z "$NO_DNS_OPT" ] ; then
-        # Tell the newly-started weaveDNS about existing weave IPs
-        with_container_addresses populate_dns_for_one_container weave:allids
-    fi
-}
-
 stop_router() {
     ! is_plugin_v1_enabled || util_op remove-plugin-network weave || true
     stop $CONTAINER_NAME "Weave"
@@ -1673,7 +1661,6 @@ EOF
         fetch_router_args
         wait_for_status $CONTAINER_NAME http_call $HTTP_ADDR
         setup_awsvpc
-        populate_router
         ;;
     launch-proxy)
         deprecation_warnings "$@"