Cmd line flag -c for config location (#108)

Add command line parsing and a flag `-c` to specify where the config
file should be loaded from.

README.md

@@ -115,7 +115,7 @@ See the INSTALL section for information on how to do this.
 
 2) Install acme-dns: `go get github.com/joohoi/acme-dns/...`. This will install acme-dns to `~/go/bin/acme-dns`.
 
-3) Edit config.cfg to suit your needs (see [configuration](#configuration)). `acme-dns` will read the configuration file from `/etc/acme-dns/config.cfg` or `./config.cfg`.
+3) Edit config.cfg to suit your needs (see [configuration](#configuration)). `acme-dns` will read the configuration file from `/etc/acme-dns/config.cfg` or `./config.cfg`, or a location specified with the `-c` flag.
 
 4) If your system has systemd, you can optionally install acme-dns as a service so that it will start on boot and be tracked by systemd. This also allows us to add the `CAP_NET_BIND_SERVICE` capability so that acme-dns can be run by a user other than root.
 
@@ -300,6 +300,9 @@ header_name = "X-Forwarded-For"
 
 
 ## Changelog
+- unreleased
+ - New
+ - Command line flag `-c` to specify location of config file.
 - v0.5
  - New
  - Configurable certificate cache directory

main.go

@@ -4,6 +4,7 @@ package main
 
 import (
  "crypto/tls"
+ "flag"
  stdlog "log"
  "net/http"
  "os"
@@ -18,11 +19,13 @@ import (
 func main() {
  // Created files are not world writable
  syscall.Umask(0077)
+ configPtr := flag.String("c", "/etc/acme-dns/config.cfg", "config file location")
+ flag.Parse()
  // Read global config
  var err error
- if fileIsAccessible("/etc/acme-dns/config.cfg") {
- log.WithFields(log.Fields{"file": "/etc/acme-dns/config.cfg"}).Info("Using config file")
- Config, err = readConfig("/etc/acme-dns/config.cfg")
+ if fileIsAccessible(*configPtr) {
+ log.WithFields(log.Fields{"file": *configPtr}).Info("Using config file")
+ Config, err = readConfig(*configPtr)
  } else if fileIsAccessible("./config.cfg") {
  log.WithFields(log.Fields{"file": "./config.cfg"}).Info("Using config file")
  Config, err = readConfig("./config.cfg")