config: Add base64sha256() function

config/interpolate_funcs.go

@@ -23,6 +23,7 @@ import (
 // Funcs is the mapping of built-in functions for configuration.
 func Funcs() map[string]ast.Function {
 	return map[string]ast.Function{
+		"base64sha256": interpolationFuncBase64Sha256(),
 		"cidrhost":     interpolationFuncCidrHost(),
 		"cidrnetmask":  interpolationFuncCidrNetmask(),
 		"cidrsubnet":   interpolationFuncCidrSubnet(),
@@ -605,6 +606,7 @@ func interpolationFuncSha1() ast.Function {
 	}
 }
 
+// hexadecimal representation of sha256 sum
 func interpolationFuncSha256() ast.Function {
 	return ast.Function{
 		ArgTypes:   []ast.Type{ast.TypeString},
@@ -629,3 +631,18 @@ func interpolationFuncTrimSpace() ast.Function {
 		},
 	}
 }
+
+func interpolationFuncBase64Sha256() ast.Function {
+	return ast.Function{
+		ArgTypes:   []ast.Type{ast.TypeString},
+		ReturnType: ast.TypeString,
+		Callback: func(args []interface{}) (interface{}, error) {
+			s := args[0].(string)
+			h := sha256.New()
+			h.Write([]byte(s))
+			shaSum := h.Sum(nil)
+			encoded := base64.StdEncoding.EncodeToString(shaSum[:])
+			return encoded, nil
+		},
+	}
+}

config/interpolate_funcs_test.go

@@ -849,7 +849,7 @@ func TestInterpolateFuncSha1(t *testing.T) {
 func TestInterpolateFuncSha256(t *testing.T) {
 	testFunction(t, testFunctionConfig{
 		Cases: []testFunctionCase{
-			{
+			{ // hexadecimal representation of sha256 sum
 				`${sha256("test")}`,
 				"9f86d081884c7d659a2feaa0c55ad015a3bf4f1b2b0b822cd15d6c15b0f00a08",
 				false,
@@ -870,6 +870,23 @@ func TestInterpolateFuncTrimSpace(t *testing.T) {
 	})
 }
 
+func TestInterpolateFuncBase64Sha256(t *testing.T) {
+	testFunction(t, testFunctionConfig{
+		Cases: []testFunctionCase{
+			{
+				`${base64sha256("test")}`,
+				"n4bQgYhMfWWaL+qgxVrQFaO/TxsrC4Is0V1sFbDwCgg=",
+				false,
+			},
+			{ // This will differ because we're base64-encoding hex represantiation, not raw bytes
+				`${base64encode(sha256("test"))}`,
+				"OWY4NmQwODE4ODRjN2Q2NTlhMmZlYWEwYzU1YWQwMTVhM2JmNGYxYjJiMGI4MjJjZDE1ZDZjMTViMGYwMGEwOA==",
+				false,
+			},
+		},
+	})
+}
+
 type testFunctionConfig struct {
 	Cases []testFunctionCase
 	Vars  map[string]ast.Variable