tracker/config/config.go

// Copyright 2013 The Chihaya Authors. All rights reserved.
// Use of this source code is governed by the BSD 2-Clause license,
// which can be found in the LICENSE file.

// Package config implements the configuration for a BitTorrent tracker
package config

import (
  "encoding/json"
  "io"
  "os"
  "time"
)

type Duration struct {
  time.Duration
}

func (d *Duration) MarshalJSON() ([]byte, error) {
  return json.Marshal(d.String())
}

func (d *Duration) UnmarshalJSON(b []byte) error {
  var str string
  err := json.Unmarshal(b, &str)
  d.Duration, err = time.ParseDuration(str)
  return err
}

// DataStore represents the configuration used to connect to a data store.
type DataStore struct {
  Driver   string `json:"driver"`
  Network  string `json:"network`
  Host     string `json:"host"`
  Port     string `json:"port"`
  Username string `json:"user"`
  Password string `json:"pass"`
  Schema   string `json:"schema,omitempty"`
  Encoding string `json:"encoding,omitempty"`
  Prefix   string `json:"prefix,omitempty"`

  MaxIdleConns int       `json:"max_idle_conns,omitempty"`
  IdleTimeout  *Duration `json:"idle_timeout,omitempty"`
}

// Config represents a configuration for a server.Server.
type Config struct {
  Addr    string    `json:"addr"`
  PubAddr string    `json:"pub_addr"`
  Cache   DataStore `json:"cache"`
  Storage DataStore `json:"storage"`

  Private   bool `json:"private"`
  Freeleech bool `json:"freeleech"`
  Slots     bool `json:"slots"`

  Announce       Duration `json:"announce"`
  MinAnnounce    Duration `json:"min_announce"`
  ReadTimeout    Duration `json:"read_timeout"`
  DefaultNumWant int      `json:"default_num_want"`
}

// Open is a shortcut to open a file, read it, and generate a Config.
// It supports relative and absolute paths.
func Open(path string) (*Config, error) {
  expandedPath := os.ExpandEnv(path)
  f, err := os.Open(expandedPath)
  if err != nil {
    return nil, err
  }
  defer f.Close()

  conf, err := newConfig(f)
  if err != nil {
    return nil, err
  }
  return conf, nil
}

// New decodes JSON from a Reader into a Config.
func newConfig(raw io.Reader) (*Config, error) {
  conf := &Config{}
  err := json.NewDecoder(raw).Decode(conf)
  if err != nil {
    return nil, err
  }
  return conf, nil
}