feat(engine): add template engine

pull/613/head
Matt Butcher 9 years ago
parent e1321bb86f
commit fa387494fb

8
glide.lock generated

@ -1,12 +1,16 @@
hash: 692bf17990973cf424c2dbfda6afee8b7002bbc07aaaa78372eac447fed4c8b0
updated: 2016-04-11T16:13:14.192550144-06:00
hash: 1dcbbc192182125021b40497fcf9d52bc643455a3bb03d6cd3458819fcb03dbb
updated: 2016-04-12T13:27:50.987288211-06:00
imports:
- name: github.com/aokoli/goutils
version: 9c37978a95bd5c709a15883b6242714ea6709e64
- name: github.com/codegangsta/cli
version: 71f57d300dd6a780ac1856c005c4b518cfd498ec
- name: github.com/golang/protobuf
version: dda510ac0fd43b39770f22ac6260eb91d377bce3
subpackages:
- proto
- name: github.com/Masterminds/sprig
version: 679bb747f11c6ffc3373965988fea8877c40b47b
- name: github.com/spf13/cobra
version: 4c05eb1145f16d0e6bb4a3e1b6d769f4713cb41f
subpackages:

@ -7,3 +7,4 @@ import:
- package: github.com/spf13/cobra
subpackages:
- cobra
- package: github.com/Masterminds/sprig

@ -0,0 +1,7 @@
/*Package engine implements the Go template engine as a Tiller Engine.
Tiller provides a simple interface for taking a Chart and rendering its templates.
The 'engine' package implements this interface using Go's built-in 'text/template'
package.
*/
package engine

@ -0,0 +1,73 @@
package engine
import (
"bytes"
"fmt"
"text/template"
"github.com/Masterminds/sprig"
"github.com/deis/tiller/pkg/hapi"
)
type Engine struct {
FuncMap template.FuncMap
}
// New creates a new Go template Engine instance.
//
// The FuncMap is initialized here. You may modify the FuncMap _prior to_ the
// first invocation of Render.
//
// The FuncMap sets all of the Sprig functions except for those that provide
// access to the underlying OS (env, expandenv).
func New() *Engine {
f := sprig.TxtFuncMap()
delete(f, "env")
delete(f, "expandenv")
return &Engine{
FuncMap: f,
}
}
// Render takes a chart, optional values, and attempts to render the Go templates.
//
// Render can be called repeatedly on the same engine.
//
// This will look in the chart's 'templates' data (e.g. the 'templates/' directory)
// and attempt to render the templates there using the values passed in.
func (e *Engine) Render(chart *hapi.Chart, vals *hapi.Values) (map[string]string, error) {
// Uncomment this once the proto files compile.
//return render(chart.Chartfile.Name, chart.Templates, vals)
return map[string]string{}, nil
}
func (e *Engine) render(name string, tpls map[string]string, v interface{}) (map[string]string, error) {
// Basically, what we do here is start with an empty parent template and then
// build up a list of templates -- one for each file. Once all of the templates
// have been parsed, we loop through again and execute every template.
//
// The idea with this process is to make it possible for more complex templates
// to share common blocks, but to make the entire thing feel like a file-based
// template engine.
t := template.New(name)
files := []string{}
for fname, tpl := range tpls {
t = t.New(fname).Funcs(e.FuncMap)
if _, err := t.Parse(tpl); err != nil {
return map[string]string{}, fmt.Errorf("parse error in %q: %s", fname, err)
}
files = append(files, fname)
}
rendered := make(map[string]string, len(files))
var buf bytes.Buffer
for _, file := range files {
if err := t.ExecuteTemplate(&buf, file, v); err != nil {
return map[string]string{}, fmt.Errorf("render error in %q: %s", file, err)
}
rendered[file] = buf.String()
buf.Reset()
}
return rendered, nil
}

@ -0,0 +1,82 @@
package engine
import (
"fmt"
"sync"
"testing"
)
func TestEngine(t *testing.T) {
e := New()
// Forbidden because they allow access to the host OS.
forbidden := []string{"env", "expandenv"}
for _, f := range forbidden {
if _, ok := e.FuncMap[f]; ok {
t.Errorf("Forbidden function %s exists in FuncMap.", f)
}
}
}
func TestRender(t *testing.T) {
t.Skip()
}
func TestRenderInternals(t *testing.T) {
// Test the internals of the rendering tool.
e := New()
tpls := map[string]string{
"one": `Hello {{title .Name}}`,
"two": `Goodbye {{upper .Value}}`,
// Test whether a template can reliably reference another template
// without regard for ordering.
"three": `{{template "two" dict "Value" "three"}}`,
}
vals := map[string]string{"Name": "one", "Value": "two"}
out, err := e.render("irrelevant", tpls, vals)
if err != nil {
t.Fatalf("Failed template rendering: %s", err)
}
if len(out) != 3 {
t.Fatalf("Expected 3 templates, got %d", len(out))
}
if out["one"] != "Hello One" {
t.Errorf("Expected 'Hello One', got %q", out["one"])
}
if out["two"] != "Goodbye TWO" {
t.Errorf("Expected 'Goodbye TWO'. got %q", out["two"])
}
if out["three"] != "Goodbye THREE" {
t.Errorf("Expected 'Goodbye THREE'. got %q", out["two"])
}
}
func TestParallelRenderInternals(t *testing.T) {
// Make sure that we can use one Engine to run parallel template renders.
e := New()
var wg sync.WaitGroup
for i := 0; i < 20; i++ {
wg.Add(1)
go func(i int) {
fname := "my/file/name"
tt := fmt.Sprintf("expect-%d", i)
tpls := map[string]string{fname: `{{.val}}`}
v := map[string]string{"val": tt}
out, err := e.render("intentionally_duplicated", tpls, v)
if err != nil {
t.Errorf("Failed to render %s: %s", tt, err)
}
if out[fname] != tt {
t.Errorf("Expected %q, got %q", tt, out[fname])
}
wg.Done()
}(i)
}
wg.Wait()
}
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