142 lines
3.9 KiB
Go
142 lines
3.9 KiB
Go
/*
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* Quick - Quick key value store for config files and persistent state files
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*
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* Quick (C) 2017 Minio, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package quick
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import (
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"bytes"
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"encoding/json"
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"fmt"
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"io/ioutil"
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"path/filepath"
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"runtime"
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"strings"
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os2 "github.com/minio/minio/pkg/x/os"
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yaml "gopkg.in/yaml.v2"
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)
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// ConfigEncoding is a generic interface which
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// marshal/unmarshal configuration.
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type ConfigEncoding interface {
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Unmarshal([]byte, interface{}) error
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Marshal(interface{}) ([]byte, error)
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}
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// YAML encoding implements ConfigEncoding
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type yamlEncoding struct{}
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func (y yamlEncoding) Unmarshal(b []byte, v interface{}) error {
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return yaml.Unmarshal(b, v)
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}
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func (y yamlEncoding) Marshal(v interface{}) ([]byte, error) {
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return yaml.Marshal(v)
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}
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// JSON encoding implements ConfigEncoding
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type jsonEncoding struct{}
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func (j jsonEncoding) Unmarshal(b []byte, v interface{}) error {
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err := json.Unmarshal(b, v)
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if err != nil {
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// Try to return a sophisticated json error message if possible
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switch jerr := err.(type) {
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case *json.SyntaxError:
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return fmt.Errorf("Unable to parse JSON schema due to a syntax error at '%s'",
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FormatJSONSyntaxError(bytes.NewReader(b), jerr.Offset))
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case *json.UnmarshalTypeError:
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return fmt.Errorf("Unable to parse JSON, type '%v' cannot be converted into the Go '%v' type",
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jerr.Value, jerr.Type)
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}
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return err
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}
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return nil
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}
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func (j jsonEncoding) Marshal(v interface{}) ([]byte, error) {
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return json.MarshalIndent(v, "", "\t")
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}
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// Convert a file extension to the appropriate struct capable
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// to marshal/unmarshal data
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func ext2EncFormat(fileExtension string) ConfigEncoding {
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// Lower the file extension
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ext := strings.ToLower(fileExtension)
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ext = strings.TrimPrefix(ext, ".")
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// Return the appropriate encoder/decoder according
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// to the extension
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switch ext {
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case "yml", "yaml":
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// YAML
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return yamlEncoding{}
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default:
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// JSON
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return jsonEncoding{}
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}
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}
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// toMarshaller returns the right marshal function according
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// to the given file extension
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func toMarshaller(ext string) func(interface{}) ([]byte, error) {
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return ext2EncFormat(ext).Marshal
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}
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// toUnmarshaller returns the right marshal function according
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// to the given file extension
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func toUnmarshaller(ext string) func([]byte, interface{}) error {
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return ext2EncFormat(ext).Unmarshal
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}
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// saveFileConfig marshals with the right encoding format
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// according to the filename extension, if no extension is
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// provided, json will be selected.
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func saveFileConfig(filename string, v interface{}) error {
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// Fetch filename's extension
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ext := filepath.Ext(filename)
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// Marshal data
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dataBytes, err := toMarshaller(ext)(v)
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if err != nil {
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return err
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}
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if runtime.GOOS == "windows" {
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dataBytes = []byte(strings.Replace(string(dataBytes), "\n", "\r\n", -1))
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}
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// Save data.
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return writeFile(filename, dataBytes)
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}
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// loadFileConfig unmarshals the file's content with the right
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// decoder format according to the filename extension. If no
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// extension is provided, json will be selected by default.
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func loadFileConfig(filename string, v interface{}) error {
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if _, err := os2.Stat(filename); err != nil {
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return err
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}
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fileData, err := ioutil.ReadFile(filename)
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if err != nil {
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return err
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}
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if runtime.GOOS == "windows" {
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fileData = []byte(strings.Replace(string(fileData), "\r\n", "\n", -1))
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}
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// Unmarshal file's content
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return toUnmarshaller(filepath.Ext(filename))(fileData, v)
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}
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