New template improvements (#388)

Signed-off-by: David Chung <david.chung@docker.com>

Author: David Chung

dockerfiles/Dockerfile.bundle

@@ -2,4 +2,11 @@ FROM alpine:3.5
 
 RUN apk add --update ca-certificates
 
+RUN mkdir -p /infrakit/plugins /infrakit/configs /infrakit/logs
+
+VOLUME /infrakit
+
+ENV INFRAKIT_HOME /infrakit
+ENV INFRAKIT_PLUGINS_DIR /infrakit/plugins
+
 ADD build/* /usr/local/bin/

pkg/template/funcs.go

@@ -114,6 +114,40 @@ func IndexOf(srch interface{}, array interface{}, strictOptional ...bool) int {
 // DefaultFuncs returns a list of default functions for binding in the template
 func (t *Template) DefaultFuncs() []Function {
 	return []Function{
+		{
+			Name: "source",
+			Description: []string{
+				"Source / evaluate the template at the input location (as URL).",
+				"This will make all of the global variables declared there visible in this template's context.",
+			},
+			Func: func(p string) (string, error) {
+				loc := p
+				if strings.Index(loc, "str://") == -1 {
+					buff, err := getURL(t.url, p)
+					if err != nil {
+						return "", err
+					}
+					loc = buff
+				}
+				sourced, err := NewTemplate(loc, t.options)
+				if err != nil {
+					return "", err
+				}
+				// copy the binds in the parent scope into the child
+				for k, v := range t.binds {
+					sourced.binds[k] = v
+				}
+				// inherit the functions defined for this template
+				for k, v := range t.funcs {
+					sourced.AddFunc(k, v)
+				}
+				// set this as the parent of the sourced template so its global can mutate the globals in this
+				sourced.parent = t
+
+				// TODO(chungers) -- let the sourced template define new functions that can be called in the parent.
+				return sourced.Render(nil)
+			},
+		},
 		{
 			Name: "include",
 			Description: []string{
@@ -187,7 +221,9 @@ func (t *Template) DefaultFuncs() []Function {
 				"Global variables are propagated to all templates that are rendered via the 'include' function.",
 			},
 			Func: func(name string, v interface{}) interface{} {
-				t.binds[name] = v
+				for here := t; here != nil; here = here.parent {
+					here.updateGlobal(name, v)
+				}
 				return ""
 			},
 		},

pkg/template/integration_test.go

@@ -169,3 +169,13 @@ func TestAddDef(t *testing.T) {
 	require.NoError(t, err)
 	require.Equal(t, "hello: x + y = 125", view)
 }
+
+func TestSourceAndGlobal(t *testing.T) {
+	r := `{{ global \"foo\" 100 }}`
+	s := `{{ source "str://` + r + `" }}foo={{ref "foo"}}`
+	tt, err := NewTemplate("str://"+s, Options{})
+	require.NoError(t, err)
+	view, err := tt.Render(nil)
+	require.NoError(t, err)
+	require.Equal(t, "foo=100", view)
+}

pkg/template/template.go

@@ -76,6 +76,8 @@ type Template struct {
 
 	registered []Function
 	lock       sync.Mutex
+
+	parent *Template
 }
 
 // NewTemplate fetches the content at the url and returns a template.  If the string begins
@@ -143,6 +145,12 @@ func (t *Template) AddDef(name string, val interface{}, doc ...string) *Template
 	return t
 }
 
+func (t *Template) updateGlobal(name string, value interface{}) {
+	t.lock.Lock()
+	defer t.lock.Unlock()
+	t.binds[name] = value
+}
+
 // Validate parses the template and checks for validity.
 func (t *Template) Validate() (*Template, error) {
 	t.lock.Lock()