daemon: Daemon.buildSandboxOptions: move vars to where they're used

Move variables closer to where they're used instead of defining them all
at the start of the function.

Also removing some intermediate variables, unwrapped some lines, and combined
some checks to a single check.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

daemon/container_operations.go

@@ -29,17 +29,8 @@ import (
 )
 
 func (daemon *Daemon) buildSandboxOptions(cfg *config.Config, container *container.Container) ([]libnetwork.SandboxOption, error) {
-	var (
-		sboxOptions []libnetwork.SandboxOption
-		err         error
-		bindings    = make(nat.PortMap)
-		pbList      []types.PortBinding
-		exposeList  []types.TransportPort
-	)
-
-	defaultNetName := runconfig.DefaultDaemonNetworkMode().NetworkName()
-	sboxOptions = append(sboxOptions, libnetwork.OptionHostname(container.Config.Hostname),
-		libnetwork.OptionDomainname(container.Config.Domainname))
+	var sboxOptions []libnetwork.SandboxOption
+	sboxOptions = append(sboxOptions, libnetwork.OptionHostname(container.Config.Hostname), libnetwork.OptionDomainname(container.Config.Domainname))
 
 	if container.HostConfig.NetworkMode.IsHost() {
 		sboxOptions = append(sboxOptions, libnetwork.OptionUseDefaultSandbox())
@@ -49,7 +40,7 @@ func (daemon *Daemon) buildSandboxOptions(cfg *config.Config, container *contain
 		sboxOptions = append(sboxOptions, libnetwork.OptionUseExternalKey())
 	}
 
-	if err = setupPathsAndSandboxOptions(container, cfg, &sboxOptions); err != nil {
+	if err := setupPathsAndSandboxOptions(container, cfg, &sboxOptions); err != nil {
 		return nil, err
 	}
 
@@ -74,7 +65,6 @@ func (daemon *Daemon) buildSandboxOptions(cfg *config.Config, container *contain
 		if container.Config.Domainname != "" {
 			name = name + "." + container.Config.Domainname
 		}
-
 		for _, a := range container.NetworkSettings.SecondaryIPAddresses {
 			sboxOptions = append(sboxOptions, libnetwork.OptionExtraHost(name, a.Addr))
 		}
@@ -99,6 +89,7 @@ func (daemon *Daemon) buildSandboxOptions(cfg *config.Config, container *contain
 		sboxOptions = append(sboxOptions, libnetwork.OptionExtraHost(host, ip))
 	}
 
+	bindings := make(nat.PortMap)
 	if container.HostConfig.PortBindings != nil {
 		for p, b := range container.HostConfig.PortBindings {
 			bindings[p] = []nat.PortBinding{}
@@ -119,11 +110,16 @@ func (daemon *Daemon) buildSandboxOptions(cfg *config.Config, container *contain
 		i++
 	}
 	nat.SortPortMap(ports, bindings)
+
+	var (
+		publishedPorts []types.PortBinding
+		exposedPorts   []types.TransportPort
+	)
 	for _, port := range ports {
 		expose := types.TransportPort{}
 		expose.Proto = types.ParseProtocol(port.Proto())
 		expose.Port = uint16(port.Int())
-		exposeList = append(exposeList, expose)
+		exposedPorts = append(exposedPorts, expose)
 
 		pb := types.PortBinding{Port: expose.Port, Proto: expose.Proto}
 		binding := bindings[port]
@@ -140,37 +136,30 @@ func (daemon *Daemon) buildSandboxOptions(cfg *config.Config, container *contain
 			pbCopy.HostPort = uint16(portStart)
 			pbCopy.HostPortEnd = uint16(portEnd)
 			pbCopy.HostIP = net.ParseIP(binding[i].HostIP)
-			pbList = append(pbList, pbCopy)
+			publishedPorts = append(publishedPorts, pbCopy)
 		}
 
 		if container.HostConfig.PublishAllPorts && len(binding) == 0 {
-			pbList = append(pbList, pb)
+			publishedPorts = append(publishedPorts, pb)
 		}
 	}
 
-	sboxOptions = append(sboxOptions,
-		libnetwork.OptionPortMapping(pbList),
-		libnetwork.OptionExposedPorts(exposeList))
+	sboxOptions = append(sboxOptions, libnetwork.OptionPortMapping(publishedPorts), libnetwork.OptionExposedPorts(exposedPorts))
 
 	// Legacy Link feature is supported only for the default bridge network.
 	// return if this call to build join options is not for default bridge network
 	// Legacy Link is only supported by docker run --link
+	defaultNetName := runconfig.DefaultDaemonNetworkMode().NetworkName()
 	bridgeSettings, ok := container.NetworkSettings.Networks[defaultNetName]
-	if !ok || bridgeSettings.EndpointSettings == nil {
-		return sboxOptions, nil
-	}
-
-	if bridgeSettings.EndpointID == "" {
+	if !ok || bridgeSettings.EndpointSettings == nil || bridgeSettings.EndpointID == "" {
 		return sboxOptions, nil
 	}
 
 	var (
-		childEndpoints, parentEndpoints []string
-		cEndpointID                     string
+		childEndpoints []string
+		cEndpointID    string
 	)
-
-	children := daemon.children(container)
-	for linkAlias, child := range children {
+	for linkAlias, child := range daemon.children(container) {
 		if !isLinkable(child) {
 			return nil, fmt.Errorf("Cannot link to %s, as it does not belong to the default network", child.Name)
 		}
@@ -181,20 +170,20 @@ func (daemon *Daemon) buildSandboxOptions(cfg *config.Config, container *contain
 		if alias != child.Name[1:] {
 			aliasList = aliasList + " " + child.Name[1:]
 		}
-		ipv4 := child.NetworkSettings.Networks[defaultNetName].IPAddress
-		ipv6 := child.NetworkSettings.Networks[defaultNetName].GlobalIPv6Address
-		if ipv4 != "" {
-			sboxOptions = append(sboxOptions, libnetwork.OptionExtraHost(aliasList, ipv4))
+		defaultNW := child.NetworkSettings.Networks[defaultNetName]
+		if defaultNW.IPAddress != "" {
+			sboxOptions = append(sboxOptions, libnetwork.OptionExtraHost(aliasList, defaultNW.IPAddress))
 		}
-		if ipv6 != "" {
-			sboxOptions = append(sboxOptions, libnetwork.OptionExtraHost(aliasList, ipv6))
+		if defaultNW.GlobalIPv6Address != "" {
+			sboxOptions = append(sboxOptions, libnetwork.OptionExtraHost(aliasList, defaultNW.GlobalIPv6Address))
 		}
-		cEndpointID = child.NetworkSettings.Networks[defaultNetName].EndpointID
+		cEndpointID = defaultNW.EndpointID
 		if cEndpointID != "" {
 			childEndpoints = append(childEndpoints, cEndpointID)
 		}
 	}
 
+	var parentEndpoints []string
 	for alias, parent := range daemon.parents(container) {
 		if cfg.DisableBridge || !container.HostConfig.NetworkMode.IsPrivate() {
 			continue
@@ -202,11 +191,7 @@ func (daemon *Daemon) buildSandboxOptions(cfg *config.Config, container *contain
 
 		_, alias = path.Split(alias)
 		log.G(context.TODO()).Debugf("Update /etc/hosts of %s for alias %s with ip %s", parent.ID, alias, bridgeSettings.IPAddress)
-		sboxOptions = append(sboxOptions, libnetwork.OptionParentUpdate(
-			parent.ID,
-			alias,
-			bridgeSettings.IPAddress,
-		))
+		sboxOptions = append(sboxOptions, libnetwork.OptionParentUpdate(parent.ID, alias, bridgeSettings.IPAddress))
 		if cEndpointID != "" {
 			parentEndpoints = append(parentEndpoints, cEndpointID)
 		}