diff --git a/nvchecker/get_version.py b/nvchecker/get_version.py
index bfb065f..e6697c2 100644
--- a/nvchecker/get_version.py
+++ b/nvchecker/get_version.py
@@ -1,167 +1,18 @@
-import re
-import sre_constants
 import logging
-from functools import partial
-import queue
-import json
-import urllib.parse
-import time
-
-from pkg_resources import parse_version
-from tornado.httpclient import AsyncHTTPClient
-import tornado.process
-from tornado.ioloop import IOLoop
+from importlib import import_module
 
 logger = logging.getLogger(__name__)
-handler_precedence = ('github', 'aur', 'pypi', 'pacman',
-                      'cmd', 'gcode_hg', 'regex')
-
-try:
-  import pycurl
-  AsyncHTTPClient.configure("tornado.curl_httpclient.CurlAsyncHTTPClient")
-except ImportError:
-  pycurl = None
+handler_precedence = (
+  'github', 'aur', 'pypi', 'pacman',
+  'cmd', 'gcode_hg', 'regex',
+)
 
 def get_version(name, conf, callback):
-  g = globals()
   for key in handler_precedence:
     if key in conf:
-      funcname = 'get_version_by_' + key
-      g[funcname](name, conf, callback)
+      func = import_module('.source.' + key, __package__).get_version
+      func(name, conf, callback)
       break
   else:
     logger.error('%s: no idea to get version info.', name)
     callback(name, None)
-
-def get_version_by_regex(name, conf, callback):
-  try:
-    r = re.compile(conf['regex'])
-  except sre_constants.error:
-    logger.warn('%s: bad regex, skipped.', name, exc_info=True)
-    callback(name, None)
-    return
-
-  encoding = conf.get('encoding', 'latin1')
-  httpclient = AsyncHTTPClient()
-
-  kwargs = {}
-  if conf.get('proxy'):
-    if pycurl:
-      host, port = urllib.parse.splitport(conf['proxy'])
-      kwargs['proxy_host'] = host
-      kwargs['proxy_port'] = int(port)
-    else:
-      logger.warn('%s: proxy set but not used because pycurl is unavailable.', name)
-
-  httpclient.fetch(conf['url'], partial(
-    _get_version_by_regex, name, r, encoding, callback
-  ), **kwargs)
-
-def _get_version_by_regex(name, regex, encoding, callback, res):
-  body = res.body.decode(encoding)
-  try:
-    version = max(regex.findall(body), key=parse_version)
-  except ValueError:
-    logger.error('%s: version string not found.', name)
-    callback(name, None)
-  else:
-    callback(name, version)
-
-AUR_URL = 'https://aur.archlinux.org/rpc.php?type=info&arg='
-
-def get_version_by_aur(name, conf, callback):
-  aurname = conf.get('aur') or name
-  url = AUR_URL + aurname
-  AsyncHTTPClient().fetch(url, partial(_aur_done, name, callback))
-
-def _aur_done(name, callback, res):
-  data = json.loads(res.body.decode('utf-8'))
-  version = data['results']['Version']
-  callback(name, version)
-
-GITHUB_URL = 'https://api.github.com/repos/%s/commits'
-
-def get_version_by_github(name, conf, callback):
-  repo = conf.get('github')
-  url = GITHUB_URL % repo
-  AsyncHTTPClient().fetch(url, user_agent='lilydjwg/nvchecker',
-                          callback=partial(_github_done, name, callback))
-
-def _github_done(name, callback, res):
-  data = json.loads(res.body.decode('utf-8'))
-  version = data[0]['commit']['committer']['date'].split('T', 1)[0].replace('-', '')
-  callback(name, version)
-
-cmd_q = queue.Queue()
-cmd_q.running = False
-
-def get_version_by_cmd(name, conf, callback):
-  cmd = conf['cmd']
-  cmd_q.put((name, cmd, callback))
-  if not cmd_q.running:
-    _run_command()
-
-def _run_command():
-  cmd_q.running = True
-  try:
-    name, cmd, callback = cmd_q.get_nowait()
-  except queue.Empty:
-    cmd_q.running = False
-    return
-
-  p = tornado.process.Subprocess(cmd, shell=True, io_loop=IOLoop.instance(),
-                                 stdout=tornado.process.Subprocess.STREAM)
-  p.set_exit_callback(partial(_command_done, name, callback, p))
-
-def _command_done(name, callback, process, status):
-  if status != 0:
-    logger.error('%s: command exited with %d.', name, status)
-    callback(name, None)
-  else:
-    process.stdout.read_until_close(partial(_got_version_from_cmd, callback, name))
-  _run_command()
-
-def _got_version_from_cmd(callback, name, output):
-  output = output.strip().decode('latin1')
-  callback(name, output)
-
-PYPI_URL = 'https://pypi.python.org/pypi/%s/json'
-
-def get_version_by_pypi(name, conf, callback):
-  repo = conf.get('pypi') or name
-  url = PYPI_URL % repo
-  AsyncHTTPClient().fetch(url, user_agent='lilydjwg/nvchecker',
-                          callback=partial(_pypi_done, name, callback))
-
-def _pypi_done(name, callback, res):
-  data = json.loads(res.body.decode('utf-8'))
-  version = data['info']['version']
-  callback(name, version)
-
-GCODE_URL = 'https://code.google.com/p/%s/source/list'
-GCODE_HG_RE = re.compile(
-  r'<a onclick="cancelBubble=true" href="detail\?r=[0-9a-f]+">([^<]+)</a>')
-
-def get_version_by_gcode_hg(name, conf, callback):
-  repo = conf.get('gcode_hg') or name
-  url = GCODE_URL % repo
-  AsyncHTTPClient().fetch(url, user_agent='lilydjwg/nvchecker',
-                          callback=partial(_gcodehg_done, name, callback))
-
-def _gcodehg_done(name, callback, res):
-  data = res.body.decode('utf-8')
-  m = GCODE_HG_RE.search(data)
-  if m:
-    t = time.strptime('Aug 15, 2013', '%b %d, %Y')
-    version = time.strftime('%Y%m%d', t)
-  else:
-    logger.error('%s: version not found.', name)
-    version = None
-  callback(name, version)
-
-
-def get_version_by_pacman(name, conf, callback):
-  referree = conf['pacman']
-  cmd = "LANG=C pacman -Si %s | grep -F Version | awk '{print $3}'" % referree
-  conf['cmd'] = cmd
-  get_version_by_cmd(name, conf, callback)
diff --git a/nvchecker/main.py b/nvchecker/main.py
index 42e9ef1..02632aa 100755
--- a/nvchecker/main.py
+++ b/nvchecker/main.py
@@ -1,11 +1,8 @@
 #!/usr/bin/env python3
 
-import os
-import sys
 import configparser
 import logging
 import argparse
-from functools import partial
 
 from pkg_resources import parse_version
 from tornado.ioloop import IOLoop
@@ -20,6 +17,7 @@ notifications = []
 g_counter = 0
 g_oldver = {}
 g_curver = {}
+args = None
 
 def task_inc():
   global g_counter
diff --git a/nvchecker/source/__init__.py b/nvchecker/source/__init__.py
new file mode 100644
index 0000000..9b5ed21
--- /dev/null
+++ b/nvchecker/source/__init__.py
@@ -0,0 +1 @@
+from .base import *
diff --git a/nvchecker/source/aur.py b/nvchecker/source/aur.py
new file mode 100644
index 0000000..d29baf5
--- /dev/null
+++ b/nvchecker/source/aur.py
@@ -0,0 +1,16 @@
+from functools import partial
+import json
+
+from tornado.httpclient import AsyncHTTPClient
+
+AUR_URL = 'https://aur.archlinux.org/rpc.php?type=info&arg='
+
+def get_version(name, conf, callback):
+  aurname = conf.get('aur') or name
+  url = AUR_URL + aurname
+  AsyncHTTPClient().fetch(url, partial(_aur_done, name, callback))
+
+def _aur_done(name, callback, res):
+  data = json.loads(res.body.decode('utf-8'))
+  version = data['results']['Version']
+  callback(name, version)
diff --git a/nvchecker/source/base.py b/nvchecker/source/base.py
new file mode 100644
index 0000000..69041c8
--- /dev/null
+++ b/nvchecker/source/base.py
@@ -0,0 +1,7 @@
+from tornado.httpclient import AsyncHTTPClient
+try:
+  import pycurl
+  AsyncHTTPClient.configure("tornado.curl_httpclient.CurlAsyncHTTPClient")
+except ImportError:
+  pycurl = None
+
diff --git a/nvchecker/source/cmd.py b/nvchecker/source/cmd.py
new file mode 100644
index 0000000..1cb1fc3
--- /dev/null
+++ b/nvchecker/source/cmd.py
@@ -0,0 +1,41 @@
+import queue
+import logging
+from functools import partial
+
+import tornado.process
+from tornado.ioloop import IOLoop
+
+logger = logging.getLogger(__name__)
+cmd_q = queue.Queue()
+cmd_q.running = False
+
+def get_version(name, conf, callback):
+  cmd = conf['cmd']
+  cmd_q.put((name, cmd, callback))
+  if not cmd_q.running:
+    _run_command()
+
+def _run_command():
+  cmd_q.running = True
+  try:
+    name, cmd, callback = cmd_q.get_nowait()
+  except queue.Empty:
+    cmd_q.running = False
+    return
+
+  p = tornado.process.Subprocess(cmd, shell=True, io_loop=IOLoop.instance(),
+                                 stdout=tornado.process.Subprocess.STREAM)
+  p.set_exit_callback(partial(_command_done, name, callback, p))
+
+def _command_done(name, callback, process, status):
+  if status != 0:
+    logger.error('%s: command exited with %d.', name, status)
+    callback(name, None)
+  else:
+    process.stdout.read_until_close(partial(_got_version_from_cmd, callback, name))
+  _run_command()
+
+def _got_version_from_cmd(callback, name, output):
+  output = output.strip().decode('latin1')
+  callback(name, output)
+
diff --git a/nvchecker/source/gcode_hg.py b/nvchecker/source/gcode_hg.py
new file mode 100644
index 0000000..0b91a4a
--- /dev/null
+++ b/nvchecker/source/gcode_hg.py
@@ -0,0 +1,29 @@
+import re
+import time
+import logging
+from functools import partial
+
+from tornado.httpclient import AsyncHTTPClient
+
+logger = logging.getLogger(__name__)
+
+GCODE_URL = 'https://code.google.com/p/%s/source/list'
+GCODE_HG_RE = re.compile(
+  r'<a onclick="cancelBubble=true" href="detail\?r=[0-9a-f]+">([^<]+)</a>')
+
+def get_version(name, conf, callback):
+  repo = conf.get('gcode_hg') or name
+  url = GCODE_URL % repo
+  AsyncHTTPClient().fetch(url, user_agent='lilydjwg/nvchecker',
+                          callback=partial(_gcodehg_done, name, callback))
+
+def _gcodehg_done(name, callback, res):
+  data = res.body.decode('utf-8')
+  m = GCODE_HG_RE.search(data)
+  if m:
+    t = time.strptime('Aug 15, 2013', '%b %d, %Y')
+    version = time.strftime('%Y%m%d', t)
+  else:
+    logger.error('%s: version not found.', name)
+    version = None
+  callback(name, version)
diff --git a/nvchecker/source/github.py b/nvchecker/source/github.py
new file mode 100644
index 0000000..814afb4
--- /dev/null
+++ b/nvchecker/source/github.py
@@ -0,0 +1,17 @@
+import json
+from functools import partial
+
+from tornado.httpclient import AsyncHTTPClient
+
+GITHUB_URL = 'https://api.github.com/repos/%s/commits'
+
+def get_version(name, conf, callback):
+  repo = conf.get('github')
+  url = GITHUB_URL % repo
+  AsyncHTTPClient().fetch(url, user_agent='lilydjwg/nvchecker',
+                          callback=partial(_github_done, name, callback))
+
+def _github_done(name, callback, res):
+  data = json.loads(res.body.decode('utf-8'))
+  version = data[0]['commit']['committer']['date'].split('T', 1)[0].replace('-', '')
+  callback(name, version)
diff --git a/nvchecker/source/pacman.py b/nvchecker/source/pacman.py
new file mode 100644
index 0000000..dc4557c
--- /dev/null
+++ b/nvchecker/source/pacman.py
@@ -0,0 +1,7 @@
+from . import cmd
+
+def get_version(name, conf, callback):
+  referree = conf['pacman']
+  c = "LANG=C pacman -Si %s | grep -F Version | awk '{print $3}'" % referree
+  conf['cmd'] = c
+  cmd.get_version(name, conf, callback)
diff --git a/nvchecker/source/pypi.py b/nvchecker/source/pypi.py
new file mode 100644
index 0000000..51f47e9
--- /dev/null
+++ b/nvchecker/source/pypi.py
@@ -0,0 +1,17 @@
+import json
+from functools import partial
+
+from tornado.httpclient import AsyncHTTPClient
+
+PYPI_URL = 'https://pypi.python.org/pypi/%s/json'
+
+def get_version(name, conf, callback):
+  repo = conf.get('pypi') or name
+  url = PYPI_URL % repo
+  AsyncHTTPClient().fetch(url, user_agent='lilydjwg/nvchecker',
+                          callback=partial(_pypi_done, name, callback))
+
+def _pypi_done(name, callback, res):
+  data = json.loads(res.body.decode('utf-8'))
+  version = data['info']['version']
+  callback(name, version)
diff --git a/nvchecker/source/regex.py b/nvchecker/source/regex.py
new file mode 100644
index 0000000..e4b81db
--- /dev/null
+++ b/nvchecker/source/regex.py
@@ -0,0 +1,46 @@
+import re
+import sre_constants
+import logging
+import urllib.parse
+from functools import partial
+
+from pkg_resources import parse_version
+from tornado.httpclient import AsyncHTTPClient
+
+from .base import pycurl
+
+logger = logging.getLogger(__name__)
+
+def get_version(name, conf, callback):
+  try:
+    r = re.compile(conf['regex'])
+  except sre_constants.error:
+    logger.warn('%s: bad regex, skipped.', name, exc_info=True)
+    callback(name, None)
+    return
+
+  encoding = conf.get('encoding', 'latin1')
+  httpclient = AsyncHTTPClient()
+
+  kwargs = {}
+  if conf.get('proxy'):
+    if pycurl:
+      host, port = urllib.parse.splitport(conf['proxy'])
+      kwargs['proxy_host'] = host
+      kwargs['proxy_port'] = int(port)
+    else:
+      logger.warn('%s: proxy set but not used because pycurl is unavailable.', name)
+
+  httpclient.fetch(conf['url'], partial(
+    _got_version, name, r, encoding, callback
+  ), **kwargs)
+
+def _got_version(name, regex, encoding, callback, res):
+  body = res.body.decode(encoding)
+  try:
+    version = max(regex.findall(body), key=parse_version)
+  except ValueError:
+    logger.error('%s: version string not found.', name)
+    callback(name, None)
+  else:
+    callback(name, version)