feat(tiller): add .Template object in templates

This allows templates to access information about the template file.
Right now, the template can only access the .Template.Name, which is the
chart-relative path to the current template.

Closes #894

pkg/chartutil/values.go

@@ -17,7 +17,7 @@ limitations under the License.
 package chartutil
 
 import (
-	"errors"
+	"fmt"
 	"io"
 	"io/ioutil"
 	"log"
@@ -28,7 +28,7 @@ import (
 )
 
 // ErrNoTable indicates that a chart does not have a matching table.
-var ErrNoTable = errors.New("no table")
+type ErrNoTable error
 
 // GlobalKey is the name of the Values key that is used for storing global vars.
 const GlobalKey = "global"
@@ -92,7 +92,7 @@ func (v Values) Encode(w io.Writer) error {
 func tableLookup(v Values, simple string) (Values, error) {
 	v2, ok := v[simple]
 	if !ok {
-		return v, ErrNoTable
+		return v, ErrNoTable(fmt.Errorf("no table named %q (%v)", simple, v))
 	}
 	if vv, ok := v2.(map[string]interface{}); ok {
 		return vv, nil
@@ -105,7 +105,8 @@ func tableLookup(v Values, simple string) (Values, error) {
 		return vv, nil
 	}
 
-	return map[string]interface{}{}, ErrNoTable
+	var e ErrNoTable = fmt.Errorf("no table named %q", simple)
+	return map[string]interface{}{}, e
 }
 
 // ReadValues will parse YAML byte data into a Values.
@@ -138,7 +139,7 @@ func ReadValuesFile(filename string) (Values, error) {
 //	- A chart has access to all of the variables for it, as well as all of
 //		the values destined for its dependencies.
 func CoalesceValues(chrt *chart.Chart, vals *chart.Config, overrides map[string]interface{}) (Values, error) {
-	var cvals Values
+	cvals := Values{}
 	// Parse values if not nil. We merge these at the top level because
 	// the passed-in values are in the same namespace as the parent chart.
 	if vals != nil {

pkg/engine/engine.go

@@ -115,9 +115,13 @@ func (e *Engine) render(tpls map[string]renderable) (map[string]string, error) {
 	rendered := make(map[string]string, len(files))
 	var buf bytes.Buffer
 	for _, file := range files {
-		if err := t.ExecuteTemplate(&buf, file, tpls[file].vals); err != nil {
+		// At render time, add information about the template that is being rendered.
+		vals := tpls[file].vals
+		vals["Template"] = map[string]interface{}{"Name": file}
+		if err := t.ExecuteTemplate(&buf, file, vals); err != nil {
 			return map[string]string{}, fmt.Errorf("render error in %q: %s", file, err)
 		}
+
 		// Work around the issue where Go will emit "<no value>" even if Options(missing=zero)
 		// is set. Since missing=error will never get here, we do not need to handle
 		// the Strict case.
@@ -142,30 +146,27 @@ func allTemplates(c *chart.Chart, vals chartutil.Values) map[string]renderable {
 // As it recurses, it also sets the values to be appropriate for the template
 // scope.
 func recAllTpls(c *chart.Chart, templates map[string]renderable, parentVals chartutil.Values, top bool) {
-	var cvals chartutil.Values
+	// This should never evaluate to a nil map. That will cause problems when
+	// values are appended later.
+	cvals := chartutil.Values{}
 	if top {
 		// If this is the top of the rendering tree, assume that parentVals
 		// is already resolved to the authoritative values.
 		cvals = parentVals
 	} else if c.Metadata != nil && c.Metadata.Name != "" {
-		// An error indicates that the table doesn't exist. So we leave it as
-		// an empty map.
-
-		var tmp chartutil.Values
-		vs, err := parentVals.Table("Values")
-		if err == nil {
-			tmp, err = vs.Table(c.Metadata.Name)
-		} else {
-			tmp, err = parentVals.Table(c.Metadata.Name)
+		// If there is a {{.Values.ThisChart}} in the parent metadata,
+		// copy that into the {{.Values}} for this template.
+		newVals := chartutil.Values{}
+		if vs, err := parentVals.Table("Values"); err == nil {
+			if tmp, err := vs.Table(c.Metadata.Name); err == nil {
+				newVals = tmp
+			}
 		}
 
-		//tmp, err := parentVals["Values"].(chartutil.Values).Table(c.Metadata.Name)
-		if err == nil {
 		cvals = map[string]interface{}{
-				"Values":  tmp,
+			"Values":  newVals,
 			"Release": parentVals["Release"],
-				"Chart":   c,
-			}
+			"Chart":   c.Metadata,
 		}
 	}
 

pkg/engine/engine_test.go

@@ -154,18 +154,21 @@ func TestParallelRenderInternals(t *testing.T) {
 
 func TestAllTemplates(t *testing.T) {
 	ch1 := &chart.Chart{
+		Metadata: &chart.Metadata{Name: "ch1"},
 		Templates: []*chart.Template{
 			{Name: "foo", Data: []byte("foo")},
 			{Name: "bar", Data: []byte("bar")},
 		},
 		Dependencies: []*chart.Chart{
 			{
+				Metadata: &chart.Metadata{Name: "laboratory mice"},
 				Templates: []*chart.Template{
 					{Name: "pinky", Data: []byte("pinky")},
 					{Name: "brain", Data: []byte("brain")},
 				},
-				Dependencies: []*chart.Chart{
-					{Templates: []*chart.Template{
+				Dependencies: []*chart.Chart{{
+					Metadata: &chart.Metadata{Name: "same thing we do every night"},
+					Templates: []*chart.Template{
 						{Name: "innermost", Data: []byte("innermost")},
 					}},
 				},
@@ -301,3 +304,49 @@ global:
 		t.Errorf("Unexpected release: %q", out[checkrelease])
 	}
 }
+
+func TestRenderBuiltinValues(t *testing.T) {
+	inner := &chart.Chart{
+		Metadata: &chart.Metadata{Name: "Latium"},
+		Templates: []*chart.Template{
+			{Name: "Lavinia", Data: []byte(`{{.Template.Name}}{{.Chart.Name}}{{.Release.Name}}`)},
+		},
+		Values:       &chart.Config{Raw: ``},
+		Dependencies: []*chart.Chart{},
+	}
+
+	outer := &chart.Chart{
+		Metadata: &chart.Metadata{Name: "Troy"},
+		Templates: []*chart.Template{
+			{Name: "Aeneas", Data: []byte(`{{.Template.Name}}{{.Chart.Name}}{{.Release.Name}}`)},
+		},
+		Values:       &chart.Config{Raw: ``},
+		Dependencies: []*chart.Chart{inner},
+	}
+
+	inject := chartutil.Values{
+		"Values": &chart.Config{Raw: ""},
+		"Chart":  outer.Metadata,
+		"Release": chartutil.Values{
+			"Name": "Aeneid",
+		},
+	}
+
+	t.Logf("Calculated values: %v", outer)
+
+	out, err := New().Render(outer, inject)
+	if err != nil {
+		t.Fatalf("failed to render templates: %s", err)
+	}
+
+	expects := map[string]string{
+		"Lavinia": "LaviniaLatiumAeneid",
+		"Aeneas":  "AeneasTroyAeneid",
+	}
+	for file, expect := range expects {
+		if out[file] != expect {
+			t.Errorf("Expected %q, got %q", expect, out[file])
+		}
+	}
+
+}