Make the exposed LoadBuildConfigFromFile a method on DockerBuildConfig

Signed-off-by: Razieh Behjati <razieh@google.com>

internal/builders/docker/pkg/config.go

@@ -153,8 +153,17 @@ func (d *Digest) ToMap() map[string]string {
 	return map[string]string{d.Alg: d.Value}
 }
 
-// LoadBuildConfigFromFile loads build configuration from a toml file in the given path and returns an instance of BuildConfig.
-func LoadBuildConfigFromFile(path string) (*BuildConfig, error) {
+// LoadBuildConfigFromFile loads build configuration from a toml file specified
+// by the BuildConfigPath of this DockerBuildConfig. An instance of BuildConfig
+// is returned on success.
+func (dbc *DockerBuildConfig) LoadBuildConfigFromFile() (*BuildConfig, error) {
+	return loadBuildConfigFromFile(dbc.BuildConfigPath)
+}
+
+// loadBuildConfigFromFile does not validate the input path, and is therefore
+// not exposed. The corresponding method LoadBuildConfigFromFile must be called
+// on an instance of DockerBuildConfig which has a validated BuildConfigPath.
+func loadBuildConfigFromFile(path string) (*BuildConfig, error) {
 	tomlTree, err := toml.LoadFile(path)
 	if err != nil {
 		return nil, fmt.Errorf("couldn't load toml file: %v", err)

internal/builders/docker/pkg/config_test.go

@@ -21,7 +21,7 @@ import (
 )
 
 func Test_LoadBuildConfigFromFile(t *testing.T) {
-	got, err := LoadBuildConfigFromFile("../testdata/config.toml")
+	got, err := loadBuildConfigFromFile("../testdata/config.toml")
 	if err != nil {
 		t.Fatalf("couldn't load config file: %v", err)
 	}