packer: Set DebugConfigKey to true if debug is on

packer/build.go

@@ -2,6 +2,10 @@ package packer
 
 import "log"
 
+// This is the key in configurations that is set to "true" when Packer
+// debugging is enabled.
+const DebugConfigKey = "packer_config"
+
 // A Build represents a single job within Packer that is responsible for
 // building some machine image artifact. Builds are meant to be parallelized.
 type Build interface {
@@ -65,8 +69,12 @@ func (b *coreBuild) Prepare() (err error) {
 	// TODO: lock
 	b.prepareCalled = true
 
+	debugConfig := map[string]interface{}{
+		DebugConfigKey: b.debug,
+	}
+
 	// Prepare the builder
-	err = b.builder.Prepare(b.builderConfig)
+	err = b.builder.Prepare(b.builderConfig, debugConfig)
 	if err != nil {
 		log.Printf("Build '%s' prepare failure: %s\n", b.name, err)
 		return
@@ -74,7 +82,11 @@ func (b *coreBuild) Prepare() (err error) {
 
 	// Prepare the provisioners
 	for _, coreProv := range b.provisioners {
-		if err = coreProv.provisioner.Prepare(coreProv.config...); err != nil {
+		configs := make([]interface{}, len(coreProv.config), len(coreProv.config)+1)
+		copy(configs, coreProv.config)
+		configs = append(configs, debugConfig)
+
+		if err = coreProv.provisioner.Prepare(configs...); err != nil {
 			return
 		}
 	}

packer/build_test.go

@@ -33,20 +33,40 @@ func TestBuild_Name(t *testing.T) {
 func TestBuild_Prepare(t *testing.T) {
 	assert := asserts.NewTestingAsserts(t, true)
 
-	build := testBuild()
+	debugFalseConfig := map[string]interface{}{DebugConfigKey: false}
 
+	build := testBuild()
 	coreB := build.(*coreBuild)
 	builder := coreB.builder.(*TestBuilder)
 
 	build.Prepare()
 	assert.True(builder.prepareCalled, "prepare should be called")
-	assert.Equal(builder.prepareConfig, []interface{}{42}, "prepare config should be 42")
+	assert.Equal(builder.prepareConfig, []interface{}{42, debugFalseConfig}, "prepare config should be 42")
 
-	// Verify provisioners were prepared
 	coreProv := coreB.provisioners[0]
 	prov := coreProv.provisioner.(*TestProvisioner)
 	assert.True(prov.prepCalled, "prepare should be called")
-	assert.Equal(prov.prepConfigs, []interface{}{42}, "prepare should be called with proper config")
+	assert.Equal(prov.prepConfigs, []interface{}{42, debugFalseConfig}, "prepare should be called with proper config")
+}
+
+func TestBuild_Prepare_Debug(t *testing.T) {
+	assert := asserts.NewTestingAsserts(t, true)
+
+	debugConfig := map[string]interface{}{DebugConfigKey: true}
+
+	build := testBuild()
+	coreB := build.(*coreBuild)
+	builder := coreB.builder.(*TestBuilder)
+
+	build.SetDebug(true)
+	build.Prepare()
+	assert.True(builder.prepareCalled, "prepare should be called")
+	assert.Equal(builder.prepareConfig, []interface{}{42, debugConfig}, "prepare config should be 42")
+
+	coreProv := coreB.provisioners[0]
+	prov := coreProv.provisioner.(*TestProvisioner)
+	assert.True(prov.prepCalled, "prepare should be called")
+	assert.Equal(prov.prepConfigs, []interface{}{42, debugConfig}, "prepare should be called with proper config")
 }
 
 func TestBuild_Run(t *testing.T) {