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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package config
import (
"fmt"
"io"
"os"
"path/filepath"
"sort"
"sync"
"gopkg.in/yaml.v3"
)
// Config represents a thread-safe key-value config, which can be marshalled to YAML.
type Config struct {
values map[string]string
mu sync.RWMutex
}
// New creates a new config.
func New() *Config { return &Config{values: make(map[string]string)} }
// Keys returns a sorted slice of keys set in this config.
func (c *Config) Keys() []string {
var keys []string
for k := range c.values {
keys = append(keys, k)
}
sort.Strings(keys)
return keys
}
// Get returns the value associated with key.
func (c *Config) Get(key string) (string, bool) {
c.mu.RLock()
defer c.mu.RUnlock()
v, ok := c.values[key]
return v, ok
}
// Set associates key with value.
func (c *Config) Set(key, value string) {
c.mu.Lock()
defer c.mu.Unlock()
c.values[key] = value
}
// Del removes the value associated with key.
func (c *Config) Del(key string) {
c.mu.Lock()
defer c.mu.Unlock()
delete(c.values, key)
}
// Write writes config in YAML format to writer w.
func (c *Config) Write(w io.Writer) error {
c.mu.RLock()
defer c.mu.RUnlock()
if err := yaml.NewEncoder(w).Encode(c.values); err != nil {
return fmt.Errorf("failed to write config: %w", err)
}
return nil
}
// WriteFile writes the config to a temporary file in the parent directory of filename, then renames the temporary file
// to filename.
func (c *Config) WriteFile(filename string) error {
dir := filepath.Dir(filename)
f, err := os.CreateTemp(dir, "config")
if err != nil {
return err
}
defer func() {
f.Close()
os.Remove(f.Name())
}()
if err := c.Write(f); err != nil {
return err
}
if err := f.Close(); err != nil {
return err
}
return os.Rename(f.Name(), filename)
}
// Read configuration in YAML format from reader r.
func Read(r io.Reader) (*Config, error) {
config := New()
if err := yaml.NewDecoder(r).Decode(config.values); err != nil {
return nil, err
}
return config, nil
}
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