Merge pull request #2151 from mitchellh/f-paths

Add template_dir for path to template [GH-54]

helper/config/decode.go

@@ -104,6 +104,7 @@ func Decode(target interface{}, config *DecodeOpts, raws ...interface{}) error {
 // detecting things like user variables from the raw configuration params.
 func DetectContext(raws ...interface{}) (*interpolate.Context, error) {
 	var s struct {
+		TemplatePath string            `mapstructure:"packer_template_path"`
 		Vars         map[string]string `mapstructure:"packer_user_variables"`
 	}
 
@@ -114,6 +115,7 @@ func DetectContext(raws ...interface{}) (*interpolate.Context, error) {
 	}
 
 	return &interpolate.Context{
+		TemplatePath:  s.TemplatePath,
 		UserVariables: s.Vars,
 	}, nil
 }

packer/build.go

@@ -24,6 +24,9 @@ const (
 	// force build is enabled.
 	ForceConfigKey = "packer_force"
 
+	// TemplatePathKey is the path to the template that configured this build
+	TemplatePathKey = "packer_template_path"
+
 	// This key contains a map[string]string of the user variables for
 	// template processing.
 	UserVariablesConfigKey = "packer_user_variables"
@@ -78,6 +81,7 @@ type coreBuild struct {
 	hooks          map[string][]Hook
 	postProcessors [][]coreBuildPostProcessor
 	provisioners   []coreBuildProvisioner
+	templatePath   string
 	variables      map[string]string
 
 	debug         bool
@@ -125,6 +129,7 @@ func (b *coreBuild) Prepare() (warn []string, err error) {
 		BuilderTypeConfigKey:   b.builderType,
 		DebugConfigKey:         b.debug,
 		ForceConfigKey:         b.force,
+		TemplatePathKey:        b.templatePath,
 		UserVariablesConfigKey: b.variables,
 	}
 

packer/build_test.go

@@ -32,6 +32,7 @@ func testDefaultPackerConfig() map[string]interface{} {
 		BuilderTypeConfigKey:   "foo",
 		DebugConfigKey:         false,
 		ForceConfigKey:         false,
+		TemplatePathKey:        "",
 		UserVariablesConfigKey: make(map[string]string),
 	}
 }

packer/core.go

@@ -50,27 +50,10 @@ type ComponentFinder struct {
 
 // NewCore creates a new Core.
 func NewCore(c *CoreConfig) (*Core, error) {
-	// Go through and interpolate all the build names. We shuld be able
-	// to do this at this point with the variables.
-	builds := make(map[string]*template.Builder)
-	for _, b := range c.Template.Builders {
-		v, err := interpolate.Render(b.Name, &interpolate.Context{
-			UserVariables: c.Variables,
-		})
-		if err != nil {
-			return nil, fmt.Errorf(
-				"Error interpolating builder '%s': %s",
-				b.Name, err)
-		}
-
-		builds[v] = b
-	}
-
 	result := &Core{
 		components: c.Components,
 		template:   c.Template,
 		variables:  c.Variables,
-		builds:     builds,
 	}
 	if err := result.validate(); err != nil {
 		return nil, err
@@ -79,6 +62,20 @@ func NewCore(c *CoreConfig) (*Core, error) {
 		return nil, err
 	}
 
+	// Go through and interpolate all the build names. We shuld be able
+	// to do this at this point with the variables.
+	result.builds = make(map[string]*template.Builder)
+	for _, b := range c.Template.Builders {
+		v, err := interpolate.Render(b.Name, result.context())
+		if err != nil {
+			return nil, fmt.Errorf(
+				"Error interpolating builder '%s': %s",
+				b.Name, err)
+		}
+
+		result.builds[v] = b
+	}
+
 	return result, nil
 }
 
@@ -204,6 +201,7 @@ func (c *Core) Build(n string) (Build, error) {
 		builderType:    configBuilder.Type,
 		postProcessors: postProcessors,
 		provisioners:   provisioners,
+		templatePath:   c.template.Path,
 		variables:      c.variables,
 	}, nil
 }
@@ -243,7 +241,9 @@ func (c *Core) init() error {
 	}
 
 	// Go through the variables and interpolate the environment variables
-	ctx := &interpolate.Context{EnableEnv: true}
+	ctx := c.context()
+	ctx.EnableEnv = true
+	ctx.UserVariables = nil
 	for k, v := range c.template.Variables {
 		// Ignore variables that are required
 		if v.Required {
@@ -268,3 +268,10 @@ func (c *Core) init() error {
 
 	return nil
 }
+
+func (c *Core) context() *interpolate.Context {
+	return &interpolate.Context{
+		TemplatePath:  c.template.Path,
+		UserVariables: c.variables,
+	}
+}

packer/core_test.go

@@ -2,6 +2,7 @@ package packer
 
 import (
 	"os"
+	"path/filepath"
 	"reflect"
 	"testing"
 
@@ -338,6 +339,35 @@ func TestCoreBuild_postProcess(t *testing.T) {
 	}
 }
 
+func TestCoreBuild_templatePath(t *testing.T) {
+	config := TestCoreConfig(t)
+	testCoreTemplate(t, config, fixtureDir("build-template-path.json"))
+	b := TestBuilder(t, config, "test")
+	core := TestCore(t, config)
+
+	expected, _ := filepath.Abs("./test-fixtures")
+
+	build, err := core.Build("test")
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	if _, err := build.Prepare(); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	// Interpolate the config
+	var result map[string]interface{}
+	err = configHelper.Decode(&result, nil, b.PrepareConfig...)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	if result["value"] != expected {
+		t.Fatalf("bad: %#v", result)
+	}
+}
+
 func TestCoreValidate(t *testing.T) {
 	cases := []struct {
 		File string

packer/test-fixtures/build-template-path.json

+{
+    "builders": [{
+        "type": "test",
+        "value": "{{template_dir}}"
+    }]
+}

template/interpolate/funcs.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"fmt"
 	"os"
+	"path/filepath"
 	"strconv"
 	"strings"
 	"text/template"
@@ -26,6 +27,7 @@ var FuncGens = map[string]FuncGenerator{
 	"env":          funcGenEnv,
 	"isotime":      funcGenIsotime,
 	"pwd":          funcGenPwd,
+	"template_dir": funcGenTemplateDir,
 	"timestamp":    funcGenTimestamp,
 	"uuid":         funcGenUuid,
 	"user":         funcGenUser,
@@ -92,6 +94,21 @@ func funcGenPwd(ctx *Context) interface{} {
 	}
 }
 
+func funcGenTemplateDir(ctx *Context) interface{} {
+	return func() (string, error) {
+		if ctx == nil || ctx.TemplatePath == "" {
+			return "", errors.New("template path not available")
+		}
+
+		path, err := filepath.Abs(filepath.Dir(ctx.TemplatePath))
+		if err != nil {
+			return "", err
+		}
+
+		return path, nil
+	}
+}
+
 func funcGenTimestamp(ctx *Context) interface{} {
 	return func() string {
 		return strconv.FormatInt(InitTime.Unix(), 10)

template/interpolate/funcs_test.go

@@ -2,6 +2,7 @@ package interpolate
 
 import (
 	"os"
+	"path/filepath"
 	"strconv"
 	"testing"
 	"time"
@@ -116,6 +117,36 @@ func TestFuncPwd(t *testing.T) {
 	}
 }
 
+func TestFuncTemplatePath(t *testing.T) {
+	path := "foo/bar"
+	expected, _ := filepath.Abs(filepath.Dir(path))
+
+	cases := []struct {
+		Input  string
+		Output string
+	}{
+		{
+			`{{template_dir}}`,
+			expected,
+		},
+	}
+
+	ctx := &Context{
+		TemplatePath: path,
+	}
+	for _, tc := range cases {
+		i := &I{Value: tc.Input}
+		result, err := i.Render(ctx)
+		if err != nil {
+			t.Fatalf("Input: %s\n\nerr: %s", tc.Input, err)
+		}
+
+		if result != tc.Output {
+			t.Fatalf("Input: %s\n\nGot: %s", tc.Input, result)
+		}
+	}
+}
+
 func TestFuncTimestamp(t *testing.T) {
 	expected := strconv.FormatInt(InitTime.Unix(), 10)
 

template/interpolate/i.go

@@ -14,6 +14,10 @@ type Context struct {
 	// Funcs are extra functions available in the template
 	Funcs map[string]interface{}
 
+	// TemplatePath is the path to the template that this is being
+	// rendered within.
+	TemplatePath string
+
 	// UserVariables is the mapping of user variables that the
 	// "user" function reads from.
 	UserVariables map[string]string

template/parse.go

@@ -310,5 +310,11 @@ func ParseFile(path string) (*Template, error) {
 	}
 	defer f.Close()
 
-	return Parse(f)
+	tpl, err := Parse(f)
+	if err != nil {
+		return nil, err
+	}
+
+	tpl.Path = path
+	return tpl, nil
 }

template/parse_test.go

@@ -272,11 +272,15 @@ func TestParse(t *testing.T) {
 	}
 
 	for _, tc := range cases {
+		path := fixtureDir(tc.File)
 		tpl, err := ParseFile(fixtureDir(tc.File))
 		if (err != nil) != tc.Err {
 			t.Fatalf("err: %s", err)
 		}
 
+		if tc.Result != nil {
+			tc.Result.Path = path
+		}
 		if tpl != nil {
 			tpl.RawContents = nil
 		}

template/template.go

@@ -11,6 +11,10 @@ import (
 // Template represents the parsed template that is used to configure
 // Packer builds.
 type Template struct {
+	// Path is the path to the template. This will be blank if Parse is
+	// used, but will be automatically populated by ParseFile.
+	Path string
+
 	Description string
 	MinVersion  string
 

website/source/docs/templates/configuration-templates.html.markdown

@@ -55,10 +55,11 @@ While some configuration settings have local variables specific to only that
 configuration, a set of functions are available globally for use in _any string_
 in Packer templates. These are listed below for reference.
 
-* `lower` - Lowercases the string.
-* `pwd` - The working directory while executing Packer.
 * `isotime [FORMAT]` - UTC time, which can be [formatted](http://golang.org/pkg/time/#example_Time_Format).
    See more examples below.
+* `lower` - Lowercases the string.
+* `pwd` - The working directory while executing Packer.
+* `template_dir` - The directory to the template for the build.
 * `timestamp` - The current Unix timestamp in UTC.
 * `uuid` - Returns a random UUID.
 * `upper` - Uppercases the string.