lbcd/util/findcheckpoint/config.go
2013-10-07 10:06:15 -04:00

99 lines
3.3 KiB
Go

// Copyright (c) 2013 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package main
import (
"fmt"
"github.com/conformal/go-flags"
"os"
"path/filepath"
)
const (
minCandidates = 1
maxCandidates = 20
defaultNumCandidates = 5
)
var (
defaultDataDir = filepath.Join(btcdHomeDir(), "data")
)
// config defines the configuration options for findcheckpoint.
//
// See loadConfig for details on the configuration load process.
type config struct {
DataDir string `short:"b" long:"datadir" description:"Location of the btcd data directory"`
NumCandidates int `short:"n" long:"numcandidates" description:"Max num of checkpoint candidates to show {1-20}"`
UseGoOutput bool `short:"g" long:"gooutput" description:"Display the candidates using Go syntax that is ready to insert into the btcchain checkpoint list"`
}
// btcdHomeDir returns an OS appropriate home directory for btcd.
func btcdHomeDir() string {
// Search for Windows APPDATA first. This won't exist on POSIX OSes.
appData := os.Getenv("APPDATA")
if appData != "" {
return filepath.Join(appData, "btcd")
}
// Fall back to standard HOME directory that works for most POSIX OSes.
home := os.Getenv("HOME")
if home != "" {
return filepath.Join(home, ".btcd")
}
// In the worst case, use the current directory.
return "."
}
// loadConfig initializes and parses the config using command line options.
//
// The configuration proceeds as follows:
// 1) Start with a default config with sane settings
// 2) Pre-parse the command line to check for an alternative config file
// 3) Load configuration file overwriting defaults with any specified options
// 4) Parse CLI options and overwrite/add any specified options
//
// The above results in btcd functioning properly without any config settings
// while still allowing the user to override settings with config files and
// command line options. Command line options always take precedence.
func loadConfig() (*config, []string, error) {
// Default config.
cfg := config{
DataDir: defaultDataDir,
NumCandidates: defaultNumCandidates,
}
// Parse command line options.
parser := flags.NewParser(&cfg, flags.Default)
remainingArgs, err := parser.Parse()
if err != nil {
if e, ok := err.(*flags.Error); !ok || e.Type != flags.ErrHelp {
parser.WriteHelp(os.Stderr)
}
return nil, nil, err
}
// Validate the number of candidates.
if cfg.NumCandidates < minCandidates || cfg.NumCandidates > maxCandidates {
str := "%s: The specified number of candidates is out of " +
"range -- parsed [%v]"
err = fmt.Errorf(str, "loadConfig", cfg.NumCandidates)
fmt.Fprintln(os.Stderr, err)
parser.WriteHelp(os.Stderr)
return nil, nil, err
}
// Append the network type to the data directory so it is "namespaced"
// per network. In addition to the block database, there are other
// pieces of data that are saved to disk such as address manager state.
// All data is specific to a network, so namespacing the data directory
// means each individual piece of serialized data does not have to
// worry about changing names per network and such.
//cfg.DataDir = cleanAndExpandPath(cfg.DataDir)
cfg.DataDir = filepath.Join(cfg.DataDir, "mainnet")
return &cfg, remainingArgs, nil
}