configfiles.go

/*
 * Tencent is pleased to support the open source community by making TKEStack
 * available.
 *
 * Copyright (C) 2012-2019 Tencent. 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
 *
 * https://opensource.org/licenses/Apache-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 OF ANY KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations under the License.
 */

package configfiles

import (
	"fmt"

	"k8s.io/apimachinery/pkg/runtime/serializer"
	auditconfig "tkestack.io/tke/pkg/audit/apis/config"
	auditscheme "tkestack.io/tke/pkg/audit/apis/config/scheme"
	"tkestack.io/tke/pkg/audit/config/codec"
	utilfs "tkestack.io/tke/pkg/util/filesystem"
)

// Loader loads configuration from a storage layer
type Loader interface {
	// Load loads and returns the AuditConfiguration from the storage layer, or an error if a configuration could not be loaded
	Load() (*auditconfig.AuditConfiguration, error)
}

// fsLoader loads configuration from `configDir`
type fsLoader struct {
	// fs is the filesystem where the config files exist; can be mocked for testing
	fs utilfs.Filesystem
	// auditCodecs is the scheme used to decode config files
	auditCodecs *serializer.CodecFactory
	// auditFile is an absolute path to the file containing a serialized AuditConfiguration
	auditFile string
}

// NewFsLoader returns a Loader that loads a AuditConfiguration from the `auditFile`
func NewFsLoader(fs utilfs.Filesystem, auditFile string) (Loader, error) {
	_, auditCodecs, err := auditscheme.NewSchemeAndCodecs()
	if err != nil {
		return nil, err
	}

	return &fsLoader{
		fs:          fs,
		auditCodecs: auditCodecs,
		auditFile:   auditFile,
	}, nil
}

func (loader *fsLoader) Load() (*auditconfig.AuditConfiguration, error) {
	data, err := loader.fs.ReadFile(loader.auditFile)
	if err != nil {
		return nil, fmt.Errorf("failed to read kubelet config file %q, error: %v", loader.auditFile, err)
	}

	// no configuration is an error, some parameters are required
	if len(data) == 0 {
		return nil, fmt.Errorf("kubelet config file %q was empty", loader.auditFile)
	}

	kc, err := codec.DecodeAuditConfiguration(loader.auditCodecs, data)
	if err != nil {
		return nil, err
	}

	// make all paths absolute
	return kc, nil
}