config: detect variables in form of resource.name.*.blah

config/loader_test.go

@@ -238,6 +238,10 @@ aws_instance[web] (x1)
   vars
     resource: aws_security_group.firewall.foo
     user: var.foo
+aws_instance[db] (x1)
+  security_groups
+  vars
+    resource: aws_security_group.firewall.*.id
 `
 
 const basicVariablesStr = `

config/test-fixtures/basic.tf

@@ -28,3 +28,7 @@ resource aws_instance "web" {
         description = "Main network interface"
     }
 }
+
+resource "aws_instance" "db" {
+    security_groups = "${aws_security_group.firewall.*.id}"
+}

config/variable.go

@@ -13,7 +13,7 @@ import (
 var varRegexp *regexp.Regexp
 
 func init() {
-	varRegexp = regexp.MustCompile(`(?i)(\$+)\{([-.a-z0-9_]+)\}`)
+	varRegexp = regexp.MustCompile(`(?i)(\$+)\{([*-.a-z0-9_]+)\}`)
 }
 
 // ReplaceVariables takes a configuration and a mapping of variables

config/variable_test.go

@@ -87,6 +87,22 @@ func TestVariableDetectWalker_resource(t *testing.T) {
 	}
 }
 
+func TestVariableDetectWalker_resourceMulti(t *testing.T) {
+	w := new(variableDetectWalker)
+
+	str := `foo ${ec2.foo.*.bar}`
+	if err := w.Primitive(reflect.ValueOf(str)); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	if len(w.Variables) != 1 {
+		t.Fatalf("bad: %#v", w.Variables)
+	}
+	if w.Variables["ec2.foo.*.bar"].(*ResourceVariable).FullKey() != "ec2.foo.*.bar" {
+		t.Fatalf("bad: %#v", w.Variables)
+	}
+}
+
 func TestVariableDetectWalker_bad(t *testing.T) {
 	w := new(variableDetectWalker)