common: Allow user variables to be used for ints/bools/etc. [GH-418]

CHANGELOG.md

@@ -8,6 +8,8 @@ FEATURES:
 
 IMPROVEMENTS:
 
+* core: User variables can now be used for integer, boolean, etc.
+  values. [GH-418]
 * builder/amazon/all: Interrupts work while waiting for AMI to be ready.
 
 BUG FIXES:

common/config.go

@@ -41,8 +41,9 @@ func CheckUnusedConfig(md *mapstructure.Metadata) *packer.MultiError {
 func DecodeConfig(target interface{}, raws ...interface{}) (*mapstructure.Metadata, error) {
 	var md mapstructure.Metadata
 	decoderConfig := &mapstructure.DecoderConfig{
-		Metadata: &md,
-		Result:   target,
+		Metadata:         &md,
+		Result:           target,
+		WeaklyTypedInput: true,
 	}
 
 	decoder, err := mapstructure.NewDecoder(decoderConfig)

website/source/docs/templates/user-variables.html.markdown

@@ -54,7 +54,7 @@ validation will fail.
 
 Using the variables is extremely easy. Variables are used by calling
 the user function in the form of <code>{{user &#96;variable&#96;}}</code>.
-This function can be used in _any string_ within the template, in
+This function can be used in _any value_ within the template, in
 builders, provisioners, _anything_. The user variable is available globally
 within the template.