Add new `packer_version` function.

Signed-off-by: Krzysztof Wilczynski <kw@linux.com>

template/interpolate/funcs.go

@@ -11,6 +11,7 @@ import (
 	"time"
 
 	"github.com/hashicorp/packer/common/uuid"
+	"github.com/hashicorp/packer/version"
 )
 
 // InitTime is the UTC time when this package was initialized. It is
@@ -33,6 +34,7 @@ var FuncGens = map[string]FuncGenerator{
 	"timestamp":      funcGenTimestamp,
 	"uuid":           funcGenUuid,
 	"user":           funcGenUser,
+	"packer_version": funcGenPackerVersion,
 
 	"upper": funcGenPrimitive(strings.ToUpper),
 	"lower": funcGenPrimitive(strings.ToLower),
@@ -152,3 +154,9 @@ func funcGenUuid(ctx *Context) interface{} {
 		return uuid.TimeOrderedUUID()
 	}
 }
+
+func funcGenPackerVersion(ctx *Context) interface{} {
+	return func() string {
+		return version.FormattedVersion()
+	}
+}

template/interpolate/funcs_test.go

@@ -4,8 +4,11 @@ import (
 	"os"
 	"path/filepath"
 	"strconv"
+	"strings"
 	"testing"
 	"time"
+
+	"github.com/hashicorp/packer/version"
 )
 
 func TestFuncBuildName(t *testing.T) {
@@ -257,3 +260,21 @@ func TestFuncUser(t *testing.T) {
 		}
 	}
 }
+
+func TestFuncPackerVersion(t *testing.T) {
+	template := `{{packer_version}}`
+
+	ctx := &Context{}
+	i := &I{Value: template}
+
+	result, err := i.Render(ctx)
+	if err != nil {
+		t.Fatalf("Input: %s\n\nerr: %s", template, err)
+	}
+
+	// Only match the X.Y.Z portion of the whole version string.
+	if !strings.HasPrefix(result, version.Version) {
+		t.Fatalf("Expected input to include: %s\n\nGot: %s",
+			version.Version, result)
+	}
+}

website/source/docs/templates/engine.html.md

@@ -43,6 +43,7 @@ Here is a full list of the available functions for reference.
 -   `uuid` - Returns a random UUID.
 -   `upper` - Uppercases the string.
 -   `user` - Specifies a user variable.
+-   `packer_version` - Returns Packer version.
 
 #### Specific to Amazon builders: