Template can create Builds

packer/build.go

@@ -7,6 +7,7 @@ package packer
 type Build struct {
 	name    string
 	builder Builder
+	rawConfig interface{}
 
 	prepareCalled bool
 }
@@ -43,9 +44,9 @@ func (NilBuilderFactory) CreateBuilder(name string) Builder {
 
 // Prepare prepares the build by doing some initialization for the builder
 // and any hooks. This _must_ be called prior to Run.
-func (b *Build) Prepare(config interface{}) {
+func (b *Build) Prepare() {
 	b.prepareCalled = true
-	b.builder.Prepare(config)
+	b.builder.Prepare(b.rawConfig)
 }
 
 // Runs the actual build. Prepare must be called prior to running this.

packer/build_test.go

@@ -5,6 +5,14 @@ import (
 	"testing"
 )
 
+type hashBuilderFactory struct {
+	builderMap map[string]Builder
+}
+
+func (bf *hashBuilderFactory) CreateBuilder(name string) Builder {
+	return bf.builderMap[name]
+}
+
 type TestBuilder struct {
 	prepareCalled bool
 	prepareConfig interface{}
@@ -28,17 +36,25 @@ func testBuild() *Build {
 	return &Build{
 		name: "test",
 		builder: &TestBuilder{},
+		rawConfig: 42,
 	}
 }
 
+func testBuilder() *TestBuilder {
+	return &TestBuilder{}
+}
+
+func testBuildFactory(builderMap map[string]Builder) BuilderFactory {
+	return &hashBuilderFactory{builderMap}
+}
+
 func TestBuild_Prepare(t *testing.T) {
 	assert := asserts.NewTestingAsserts(t, true)
 
 	build := testBuild()
-	build.Prepare(42)
-
 	builder := build.builder.(*TestBuilder)
 
+	build.Prepare()
 	assert.True(builder.prepareCalled, "prepare should be called")
 	assert.Equal(builder.prepareConfig, 42, "prepare config should be 42")
 }
@@ -49,7 +65,7 @@ func TestBuild_Run(t *testing.T) {
 	ui := testUi()
 
 	build := testBuild()
-	build.Prepare(nil)
+	build.Prepare()
 	build.Run(ui)
 
 	builder := build.builder.(*TestBuilder)

packer/template.go

 package packer
 
-import "encoding/json"
+import (
+	"encoding/json"
+	"fmt"
+)
 
 // The rawTemplate struct represents the structure of a template read
 // directly from a file. The builders and other components map just to
@@ -74,3 +77,42 @@ func ParseTemplate(data []byte) (t *Template, err error) {
 
 	return
 }
+
+// BuildNames returns a slice of the available names of builds that
+// this template represents.
+func (t *Template) BuildNames() []string {
+	names := make([]string, len(t.Builders))
+	i := 0
+	for name, _ := range t.Builders {
+		names[i] = name
+		i++
+	}
+
+	return names
+}
+
+// Build returns a Build for the given name.
+//
+// If the build does not exist as part of this template, an error is
+// returned.
+func (t *Template) Build(name string, bf BuilderFactory) (b *Build, err error) {
+	builderConfig, ok := t.Builders[name]
+	if !ok {
+		err = fmt.Errorf("No such build found in template: %s", name)
+		return
+	}
+
+	builder := bf.CreateBuilder(builderConfig.builderName)
+	if builder == nil {
+		err = fmt.Errorf("Builder could not be found: %s", builderConfig.builderName)
+		return
+	}
+
+	b = &Build{
+		name: name,
+		builder: builder,
+		rawConfig: builderConfig.rawConfig,
+	}
+
+	return
+}

packer/template_test.go

@@ -2,6 +2,7 @@ package packer
 
 import (
 	"cgl.tideland.biz/asserts"
+	"sort"
 	"testing"
 )
 
@@ -87,3 +88,121 @@ func TestParseTemplate_BuilderWithName(t *testing.T) {
 	assert.True(ok, "should have bob builder")
 	assert.Equal(builder.builderName, "amazon-ebs", "builder should be amazon-ebs")
 }
+
+func TestTemplate_BuildNames(t *testing.T) {
+	assert := asserts.NewTestingAsserts(t, true)
+
+	data := `
+	{
+		"name": "my-image",
+		"builders": [
+			{
+				"name": "bob",
+				"type": "amazon-ebs"
+			},
+			{
+				"name": "chris",
+				"type": "another"
+			}
+		]
+	}
+	`
+
+	result, err := ParseTemplate([]byte(data))
+	assert.Nil(err, "should not error")
+
+	buildNames := result.BuildNames()
+	sort.Strings(buildNames)
+	assert.Equal(buildNames, []string{"bob", "chris"}, "should have proper builds")
+}
+
+func TestTemplate_BuildUnknown(t *testing.T) {
+	assert := asserts.NewTestingAsserts(t, true)
+
+	data := `
+	{
+		"name": "my-image",
+		"builders": [
+			{
+				"name": "test1",
+				"type": "test-builder"
+			}
+		]
+	}
+	`
+
+	template, err := ParseTemplate([]byte(data))
+	assert.Nil(err, "should not error")
+
+	build, err := template.Build("nope", nil)
+	assert.Nil(build, "build should be nil")
+	assert.NotNil(err, "should have error")
+}
+
+func TestTemplate_BuildUnknownBuilder(t *testing.T) {
+	assert := asserts.NewTestingAsserts(t, true)
+
+	data := `
+	{
+		"name": "my-image",
+		"builders": [
+			{
+				"name": "test1",
+				"type": "test-builder"
+			}
+		]
+	}
+	`
+
+	template, err := ParseTemplate([]byte(data))
+	assert.Nil(err, "should not error")
+
+	builderFactory := testBuildFactory(map[string]Builder{})
+	build, err := template.Build("test1", builderFactory)
+	assert.Nil(build, "build should be nil")
+	assert.NotNil(err, "should have error")
+}
+
+func TestTemplate_Build(t *testing.T) {
+	assert := asserts.NewTestingAsserts(t, true)
+
+	data := `
+	{
+		"name": "my-image",
+		"builders": [
+			{
+				"name": "test1",
+				"type": "test-builder"
+			}
+		]
+	}
+	`
+
+	expectedConfig := map[string]interface{} {
+		"name": "test1",
+		"type": "test-builder",
+	}
+
+	template, err := ParseTemplate([]byte(data))
+	assert.Nil(err, "should not error")
+
+	builder := testBuilder()
+	builderMap := map[string]Builder {
+		"test-builder": builder,
+	}
+
+	builderFactory := testBuildFactory(builderMap)
+
+	// Get the build, verifying we can get it without issue, but also
+	// that the proper builder was looked up and used for the build.
+	build, err := template.Build("test1", builderFactory)
+	assert.Nil(err, "should not error")
+
+	build.Prepare()
+	build.Run(testUi())
+
+	assert.True(builder.prepareCalled, "prepare should be called")
+	assert.Equal(builder.prepareConfig, expectedConfig, "prepare config should be correct")
+	assert.True(builder.runCalled, "run should be called")
+	assert.Equal(builder.runBuild, build, "run should be called with build")
+}