Export pkg config/engine

Signed-off-by: Carlos Eduardo Arango Gutierrez <eduardoa@nvidia.com>

pkg/config/engine/docker/option.go

@@ -0,0 +1,80 @@
+/**
+# Copyright (c) NVIDIA CORPORATION.  All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+**/
+
+package docker
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"os"
+
+	log "github.com/sirupsen/logrus"
+)
+
+type builder struct {
+	path string
+}
+
+// Option defines a function that can be used to configure the config builder
+type Option func(*builder)
+
+// WithPath sets the path for the config builder
+func WithPath(path string) Option {
+	return func(b *builder) {
+		b.path = path
+	}
+}
+
+func (b *builder) build() (*Config, error) {
+	if b.path == "" {
+		empty := make(Config)
+		return &empty, nil
+	}
+
+	return loadConfig(b.path)
+}
+
+// loadConfig loads the docker config from disk
+func loadConfig(configFilePath string) (*Config, error) {
+	log.Infof("Loading docker config from %v", configFilePath)
+
+	info, err := os.Stat(configFilePath)
+	if os.IsExist(err) && info.IsDir() {
+		return nil, fmt.Errorf("config file is a directory")
+	}
+
+	cfg := make(Config)
+
+	if os.IsNotExist(err) {
+		log.Infof("Config file does not exist, creating new one")
+		return &cfg, nil
+	}
+
+	readBytes, err := ioutil.ReadFile(configFilePath)
+	if err != nil {
+		return nil, fmt.Errorf("unable to read config: %v", err)
+	}
+
+	reader := bytes.NewReader(readBytes)
+	if err := json.NewDecoder(reader).Decode(&cfg); err != nil {
+		return nil, err
+	}
+
+	log.Infof("Successfully loaded config")
+	return &cfg, nil
+}