Add 'nomad.advertise.address' to client meta via NomadFingerPrint

This change removes the addition of the advertise address to the
exported task env vars and instead moves this work into the
NomadFingerprint.Fingerprint which adds this value to the client
attrs. This can then be used within a Nomad job like
${attr.nomad.advertise.address}.

client/driver/env/env.go

@@ -59,10 +59,6 @@ const (
 	// Region is the environment variable for passing the region in which the alloc is running.
 	Region = "NOMAD_REGION"
 
-	// NomadAdvertiseAddr is the environment variable for passing the client HTTP
-	// advertise address. GH-4381.
-	NomadAdvertiseAddr = "NOMAD_ADVERTISE_ADDR"
-
 	// AddrPrefix is the prefix for passing both dynamic and static port
 	// allocations to tasks.
 	// E.g $NOMAD_ADDR_http=127.0.0.1:80
@@ -211,19 +207,18 @@ type Builder struct {
 	// secretsDir from task's perspective; eg /secrets
 	secretsDir string
 
-	cpuLimit           int
-	memLimit           int
-	taskName           string
-	allocIndex         int
-	datacenter         string
-	region             string
-	nomadAdvertiseAddr string
-	allocId            string
-	allocName          string
-	groupName          string
-	vaultToken         string
-	injectVaultToken   bool
-	jobName            string
+	cpuLimit         int
+	memLimit         int
+	taskName         string
+	allocIndex       int
+	datacenter       string
+	region           string
+	allocId          string
+	allocName        string
+	groupName        string
+	vaultToken       string
+	injectVaultToken bool
+	jobName          string
 
 	// otherPorts for tasks in the same alloc
 	otherPorts map[string]string
@@ -311,9 +306,6 @@ func (b *Builder) Build() *TaskEnv {
 		// Copy region over to node attrs
 		nodeAttrs[nodeRegionKey] = b.region
 	}
-	if b.nomadAdvertiseAddr != "" {
-		envMap[NomadAdvertiseAddr] = b.nomadAdvertiseAddr
-	}
 
 	// Build the network related env vars
 	buildNetworkEnv(envMap, b.networks, b.driverNetwork)
@@ -453,7 +445,6 @@ func (b *Builder) setNode(n *structs.Node) *Builder {
 	b.nodeAttrs[nodeClassKey] = n.NodeClass
 	b.nodeAttrs[nodeDcKey] = n.Datacenter
 	b.datacenter = n.Datacenter
-	b.nomadAdvertiseAddr = n.HTTPAddr
 
 	// Set up the attributes.
 	for k, v := range n.Attributes {

client/fingerprint/nomad.go

@@ -19,6 +19,7 @@ func NewNomadFingerprint(logger *log.Logger) Fingerprint {
 }
 
 func (f *NomadFingerprint) Fingerprint(req *cstructs.FingerprintRequest, resp *cstructs.FingerprintResponse) error {
+	resp.AddAttribute("nomad.advertise.address", req.Node.HTTPAddr)
 	resp.AddAttribute("nomad.version", req.Config.Version.VersionNumber())
 	resp.AddAttribute("nomad.revision", req.Config.Version.Revision)
 	resp.Detected = true

client/fingerprint/nomad_test.go

@@ -11,17 +11,20 @@ import (
 
 func TestNomadFingerprint(t *testing.T) {
 	f := NewNomadFingerprint(testLogger())
-	node := &structs.Node{
-		Attributes: make(map[string]string),
-	}
+
 	v := "foo"
 	r := "123"
+	h := "8.8.8.8:4646"
 	c := &config.Config{
 		Version: &version.VersionInfo{
 			Revision: r,
 			Version:  v,
 		},
 	}
+	node := &structs.Node{
+		Attributes: make(map[string]string),
+		HTTPAddr:   h,
+	}
 
 	request := &cstructs.FingerprintRequest{Config: c, Node: node}
 	var response cstructs.FingerprintResponse
@@ -45,4 +48,8 @@ func TestNomadFingerprint(t *testing.T) {
 	if response.Attributes["nomad.revision"] != r {
 		t.Fatalf("incorrect revision")
 	}
+
+	if response.Attributes["nomad.advertise.address"] != h {
+		t.Fatalf("incorrect advertise address")
+	}
 }