common.py: Print URL of get_content call when --debug is enabled

Use logging, and raise the root logger level from WARNING (default) to
DEBUG when --debug is enabled.

This logging facility can be extended to other functions.

src/you_get/common.py

@@ -91,6 +91,7 @@ SITES = {
 import getopt
 import json
 import locale
+import logging
 import os
 import platform
 import re
@@ -298,6 +299,8 @@ def get_content(url, headers={}, decoded=True):
         The content as a string.
     """
 
+    logging.debug('get_content: %s' % url)
+
     req = request.Request(url, headers=headers)
     if cookies:
         cookies.add_cookie_header(req)
@@ -1032,6 +1035,8 @@ def script_main(script_name, download, download_playlist, **kwargs):
               % get_version(kwargs['repo_path']
             if 'repo_path' in kwargs else __version__))
 
+    logging.basicConfig(format='[%(levelname)s] %(message)s')
+
     help = 'Usage: %s [OPTION]... [URL]...\n\n' % script_name
     help += '''Startup options:
     -V | --version                      Print version and exit.
@@ -1055,7 +1060,7 @@ def script_main(script_name, download, download_playlist, **kwargs):
     -x | --http-proxy <HOST:PORT>       Use an HTTP proxy for downloading.
     -y | --extractor-proxy <HOST:PORT>  Use an HTTP proxy for extracting only.
          --no-proxy                     Never use a proxy.
-    -d | --debug                        Show traceback for debugging.
+    -d | --debug                        Show traceback and other debug info.
     '''
 
     short_opts = 'Vhfiuc:ndF:O:o:p:x:y:'
@@ -1145,6 +1150,8 @@ def script_main(script_name, download, download_playlist, **kwargs):
             proxy = ''
         elif o in ('-d', '--debug'):
             traceback = True
+            # Set level of root logger to DEBUG
+            logging.getLogger().setLevel(logging.DEBUG)
         elif o in ('-F', '--format', '--stream', '--itag'):
             stream_id = a
         elif o in ('-O', '--output-filename'):