template/interpolate: isotime

template/interpolate/funcs.go

@@ -2,15 +2,18 @@ package interpolate
 
 import (
 	"errors"
+	"fmt"
 	"os"
 	"text/template"
+	"time"
 )
 
 // Funcs are the interpolation funcs that are available within interpolations.
 var FuncGens = map[string]FuncGenerator{
-	"env":  funcGenEnv,
-	"pwd":  funcGenPwd,
-	"user": funcGenUser,
+	"env":     funcGenEnv,
+	"isotime": funcGenIsotime,
+	"pwd":     funcGenPwd,
+	"user":    funcGenUser,
 }
 
 // FuncGenerator is a function that given a context generates a template
@@ -40,6 +43,20 @@ func funcGenEnv(ctx *Context) interface{} {
 	}
 }
 
+func funcGenIsotime(ctx *Context) interface{} {
+	return func(format ...string) (string, error) {
+		if len(format) == 0 {
+			return time.Now().UTC().Format(time.RFC3339), nil
+		}
+
+		if len(format) > 1 {
+			return "", fmt.Errorf("too many values, 1 needed: %v", format)
+		}
+
+		return time.Now().UTC().Format(format[0]), nil
+	}
+}
+
 func funcGenPwd(ctx *Context) interface{} {
 	return func() (string, error) {
 		return os.Getwd()

template/interpolate/funcs_test.go

@@ -3,6 +3,7 @@ package interpolate
 import (
 	"os"
 	"testing"
+	"time"
 )
 
 func TestFuncEnv(t *testing.T) {
@@ -65,6 +66,25 @@ func TestFuncEnv_disable(t *testing.T) {
 	}
 }
 
+func TestFuncIsotime(t *testing.T) {
+	ctx := &Context{}
+	i := &I{Value: "{{isotime}}"}
+	result, err := i.Render(ctx)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	val, err := time.Parse(time.RFC3339, result)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	currentTime := time.Now().UTC()
+	if currentTime.Sub(val) > 2*time.Second {
+		t.Fatalf("val: %d (current: %d)", val, currentTime)
+	}
+}
+
 func TestFuncPwd(t *testing.T) {
 	wd, err := os.Getwd()
 	if err != nil {