Add checks to quit if DefaultInterface address can't be resolved

cmd/todd-agent/main.go

@@ -94,19 +94,20 @@ func main() {
 	// Watch for changes to group membership
 	go tc.Package.WatchForGroup()
 
+	// Get default IP address for the server.
+	// This address is primarily used so that the server knows how to orchestrate tests.
+	// (i.e. This agent publishes it's default address, and the server instructs other agents to target it in tests)
+	defaultaddr, err := hostresources.GetDefaultInterfaceIP(cfg.LocalResources.DefaultInterface, cfg.LocalResources.IPAddrOverride)
+	if err != nil {
+		log.Fatalf("Unable to derive address from configured DefaultInterface: %v", err)
+	}
+
 	// Continually advertise agent status into message queue
 	for {
 
 		// Gather assets here as a map, and refer to a key in that map in the below struct
 		gatheredAssets := GetLocalAssets(cfg)
 
-		var defaultaddr string
-		if cfg.LocalResources.IPAddrOverride != "" {
-			defaultaddr = cfg.LocalResources.IPAddrOverride
-		} else {
-			defaultaddr = hostresources.GetIPOfInt(cfg.LocalResources.DefaultInterface).String()
-		}
-
 		fcts, err := facts.GetFacts(cfg)
 		if err != nil {
 			log.Errorf("Error gathering facts: %v", err)

cmd/todd-server/main.go

@@ -20,6 +20,7 @@ import (
 	"github.com/toddproject/todd/comms"
 	"github.com/toddproject/todd/config"
 	"github.com/toddproject/todd/db"
+	"github.com/toddproject/todd/hostresources"
 	"github.com/toddproject/todd/server/grouping"
 )
 
@@ -81,9 +82,18 @@ func main() {
 		log.Fatalf("Problem connecting to comms: %v\n", err)
 	}
 
+	// Get default IP address for the server.
+	// This address is primarily used to inform the agents of the URL they should use to download assets
+	defaultaddr, err := hostresources.GetDefaultInterfaceIP(cfg.LocalResources.DefaultInterface, cfg.LocalResources.IPAddrOverride)
+	if err != nil {
+		log.Fatalf("Unable to derive address from configured DefaultInterface: %v", err)
+	}
+
+	assetURLPrefix := fmt.Sprintf("http://%s:%s", defaultaddr, cfg.Assets.Port)
+
 	go func() {
 		for {
-			err := tc.Package.ListenForAgent(assets)
+			err := tc.Package.ListenForAgent(assets, assetURLPrefix)
 			if err != nil {
 				log.Fatalf("Error listening for ToDD Agents")
 			}

comms/comms.go

@@ -38,8 +38,8 @@ type Package interface {
 	// (agent advertisement to advertise)
 	AdvertiseAgent(defs.AgentAdvert) error
 
-	// (map of assets:hashes, lock for asset map)
-	ListenForAgent(assetProvider) error
+	// (map of assets:hashes, base asset URL)
+	ListenForAgent(assetProvider, string) error
 
 	// (uuid)
 	ListenForTasks(string) error

comms/rabbitmq.go

@@ -24,7 +24,6 @@ import (
 	"github.com/toddproject/todd/agent/tasks"
 	"github.com/toddproject/todd/config"
 	"github.com/toddproject/todd/db"
-	"github.com/toddproject/todd/hostresources"
 )
 
 const (
@@ -165,7 +164,7 @@ func (rmq rabbitMQComms) AdvertiseAgent(me defs.AgentAdvert) error {
 
 // ListenForAgent will listen on the message queue for new agent advertisements.
 // It is meant to be run as a goroutine
-func (rmq rabbitMQComms) ListenForAgent(assets assetProvider) error {
+func (rmq rabbitMQComms) ListenForAgent(assets assetProvider, assetURLPrefix string) error {
 
 	// TODO(mierdin): does func param need to be a pointer?
 
@@ -247,14 +246,7 @@ func (rmq rabbitMQComms) ListenForAgent(assets assetProvider) error {
 					if agentAssets[name] != hash {
 
 						// hashes do not match, so we need to append the asset download URL to the remediate list
-						var defaultIP string
-						if rmq.config.LocalResources.IPAddrOverride != "" { // TODO: set defaultIP to override byte default and check if empty
-							defaultIP = rmq.config.LocalResources.IPAddrOverride
-						} else {
-							defaultIP = hostresources.GetIPOfInt(rmq.config.LocalResources.DefaultInterface).String()
-						}
-						assetURL := fmt.Sprintf("http://%s:%s/%s/%s", defaultIP, rmq.config.Assets.Port, assetType, name)
-
+						assetURL := fmt.Sprintf("%s/%s/%s", assetURLPrefix, assetType, name)
 						assetList = append(assetList, assetURL)
 
 					}

hostresources/network.go

@@ -10,32 +10,75 @@ package hostresources
 
 import (
 	"net"
+
+	"github.com/pkg/errors"
 )
 
-// GetIPOfInt will iterate over all addresses for the given network interface, but will return only
+// GetDefaultInterfaceIP determines the appropriate IP address to use for either the server or agent
+// based on configuration parameters passed in as arguments
+//
+// The server uses this address to inform the agents of the URL they should use to download assets
+//
+// The agents use this address so that the server knows how to orchestrate tests.
+// (i.e. This agent publishes it's default address, and the server instructs other agents to target it in tests)
+func GetDefaultInterfaceIP(ifname, ipAddrOverride string) (string, error) {
+	if ipAddrOverride != "" {
+		return ipAddrOverride, nil
+	}
+	return getIPOfInt(ifname)
+}
+
+// getIPOfInt will get the first usable IP address on a network interface
+//
+// TODO(mierdin): Need to handle IPv6 here
+func getIPOfInt(ifname string) (string, error) {
+
+	iface, err := net.InterfaceByName(ifname)
+	if err != nil {
+		return "", errors.Wrap(err, "Specified network interface not found")
+	}
+
+	addrs, err := iface.Addrs()
+	if err != nil {
+		return "", errors.Wrap(err, "Failed to retrieve addresses from network interface")
+	}
+
+	// Iterate over all the addresses and return the first one we find
+	for _, addr := range addrs {
+		if ipnet, ok := addr.(*net.IPNet); ok {
+			if ipnet.IP.To4() != nil {
+				return ipnet.IP.To4().String(), nil
+			}
+		}
+	}
+
+	return "", errors.New("No DefaultInterface address found")
+}
+
+// getIPOfInt will iterate over all addresses for the given network interface, but will return only
 // the first one it finds. TODO(mierdin): This has obvious drawbacks, particularly with IPv6. Need to figure out a better way.
-func GetIPOfInt(ifname string) net.IP {
+func oldgetIPOfInt(ifname string) (string, error) {
 	interfaces, err := net.Interfaces()
 	if err != nil {
-		panic(err)
+		return "", err
 	}
 
 	for _, iface := range interfaces {
 		if iface.Name == ifname {
 
 			addrs, err := iface.Addrs()
 			if err != nil {
-				panic(err)
+				return "", err
 			}
 			for _, addr := range addrs {
 				if ipnet, ok := addr.(*net.IPNet); ok {
 					if ipnet.IP.To4() != nil {
-						return ipnet.IP
+						return ipnet.IP.To4().String(), nil
 					}
 
 				}
 			}
 		}
 	}
-	return nil
+	return "", errors.New("No DefaultInterface address found")
 }

scripts/start-containers.sh

@@ -13,6 +13,9 @@ branch=$(git symbolic-ref -q HEAD)
 branch=${branch##refs/heads/}
 branch=${branch:-HEAD}
 
+# Replace any slashes in branch with hyphen, so docker doesn't puke
+branch=${branch/\//_} 
+
 toddimage=toddproject/todd:$branch
 
 if [ ${PWD:(-7)} == "scripts" ]
@@ -67,12 +70,11 @@ function startinfra {
      -initial-cluster etcd0=http://${HostIP}:2380 \
      -initial-cluster-state new > /dev/null
 
-    # I have a rabbitmq server at home, but in case I'm working on my laptop only, spin this up too:
     echo "Starting RabbitMQ"
     docker run -d \
         --net todd-network \
         --name rabbit \
-        -p 8085:15672 \
+        -p 15672:15672 \
         -p 5672:5672 \
         -e RABBITMQ_DEFAULT_USER=guest \
         -e RABBITMQ_DEFAULT_PASS=guest \
@@ -82,7 +84,6 @@ function startinfra {
     docker run -d --net todd-network --volume=/var/influxdb:/data --name influx -p 8083:8083 -p 8086:8086 tutum/influxdb:0.9 > /dev/null
     echo "Starting Grafana"
     docker run -d --net todd-network --volume=/var/lib/grafana:/var/lib/grafana --name grafana -p 3000:3000 grafana/grafana > /dev/null
-
 }
 
 # arg $1: number of agents to use