Add ENV TF_HOSTNAME_KEY_NAME to specify which hostname to return

Overwrite with the environment variable TF_HOSTNAME_KEY_NAME which attribute is to be used for the ansible inventory name.
By default, the IP address is used. The Ansible variable "ansible_host" is used to connect to the host.

README.md

@@ -146,6 +146,11 @@ to `private_ip` before running the playbook, like:
 
 	TF_KEY_NAME=private_ip ansible-playbook --inventory-file=/path/to/terraform-inventory deploy/playbook.yml
 
+By default, the ip address is the ansible inventory name. The `TF_HOSTNAME_KEY_NAME` environment variable allows
+you to overwrite the source of the ansible inventory name.
+
+	TF_HOSTNAME_KEY_NAME=name ansible-playbook --inventory-file=/path/to/terraform-inventory deploy/playbook.yml
+
 ## Development
 
 It's just a Go app, so the usual:

cli.go

@@ -55,20 +55,20 @@ func gatherResources(s *state) map[string]interface{} {
 
 	for _, res := range s.resources() {
 		// place in list of all resources
-		all.Hosts = appendUniq(all.Hosts, res.Address())
+		all.Hosts = appendUniq(all.Hosts, res.Hostname())
 
 		// place in list of resource types
 		tp := fmt.Sprintf("type_%s", res.resourceType)
-		types[tp] = appendUniq(types[tp], res.Address())
+		types[tp] = appendUniq(types[tp], res.Hostname())
 
 		unsortedOrdered[res.baseName] = append(unsortedOrdered[res.baseName], res)
 
 		// store as invdividual host (eg. <name>.<count>)
 		invdName := fmt.Sprintf("%s.%d", res.baseName, res.counter)
 		if old, exists := individual[invdName]; exists {
-			fmt.Fprintf(os.Stderr, "overwriting already existing individual key %s, old: %v, new: %v", invdName, old, res.Address())
+			fmt.Fprintf(os.Stderr, "overwriting already existing individual key %s, old: %v, new: %v", invdName, old, res.Hostname())
 		}
-		individual[invdName] = []string{res.Address()}
+		individual[invdName] = []string{res.Hostname()}
 
 		// inventorize tags
 		for k, v := range res.Tags() {
@@ -77,7 +77,7 @@ func gatherResources(s *state) map[string]interface{} {
 			if v != "" {
 				tag = fmt.Sprintf("%s_%s", k, v)
 			}
-			tags[tag] = appendUniq(tags[tag], res.Address())
+			tags[tag] = appendUniq(tags[tag], res.Hostname())
 		}
 	}
 
@@ -94,7 +94,7 @@ func gatherResources(s *state) map[string]interface{} {
 		sort.Sort(cs)
 
 		for i := range resources {
-			ordered[basename] = append(ordered[basename], resources[i].Address())
+			ordered[basename] = append(ordered[basename], resources[i].Hostname())
 		}
 	}
 
@@ -187,8 +187,10 @@ func checkErr(err error, stderr io.Writer) int {
 
 func cmdHost(stdout io.Writer, stderr io.Writer, s *state, hostname string) int {
 	for _, res := range s.resources() {
-		if hostname == res.Address() {
-			return output(stdout, stderr, res.Attributes())
+		if hostname == res.Hostname() {
+			attributes := res.Attributes()
+			attributes["ansible_host"] = res.Address()
+			return output(stdout, stderr, attributes)
 		}
 	}
 

parser_test.go

@@ -610,6 +610,7 @@ olddatacenter="\u003c0.7_format"
 
 const expectedHostOneOutput = `
 {
+	"ansible_host": "10.0.0.1",
 	"id":"i-aaaaaaaa",
 	"private_ip":"10.0.0.1",
 	"tags.#": "1",

resource.go

@@ -163,6 +163,17 @@ func (r Resource) NameWithCounter() string {
 	return fmt.Sprintf("%s.%d", r.baseName, r.counter)
 }
 
+// Hostname returns the hostname of this resource.
+func (r Resource) Hostname() string {
+	if keyName := os.Getenv("TF_HOSTNAME_KEY_NAME"); keyName != "" {
+		if ip := r.State.Primary.Attributes[keyName]; ip != "" {
+			return ip
+		}
+	}
+
+	return r.Address()
+}
+
 // Address returns the IP address of this resource.
 func (r Resource) Address() string {
 	if keyName := os.Getenv("TF_KEY_NAME"); keyName != "" {