#280: Add debug output

README.md

@@ -253,7 +253,8 @@ The Fuck has a few settings parameters which can be changed in `~/.thefuck/setti
 * `require_confirmation` – requires confirmation before running new command, by default `False`;
 * `wait_command` – max amount of time in seconds for getting previous command output;
 * `no_colors` – disable colored output;
-* `priority` – dict with rules priorities, rule with lower `priority` will be matched first.
+* `priority` – dict with rules priorities, rule with lower `priority` will be matched first;
+* `debug` – enabled debug output, by default `False`;
 
 Example of `settings.py`:
 
@@ -263,6 +264,7 @@ require_confirmation = True
 wait_command = 10
 no_colors = False
 priority = {'sudo': 100, 'no_command': 9999}
+debug = False
 ```
 
 Or via environment variables:
@@ -272,7 +274,8 @@ Or via environment variables:
 * `THEFUCK_WAIT_COMMAND` – max amount of time in seconds for getting previous command output;
 * `THEFUCK_NO_COLORS` – disable colored output, `true/false`;
 * `THEFUCK_PRIORITY` – priority of the rules, like `no_command=9999:apt_get=100`,
-rule with lower `priority` will be matched first.
+rule with lower `priority` will be matched first;
+* `THEFUCK_DEBUG` – enables debug output, `true/false`.
 
 For example:
 

tests/test_logs.py

@@ -5,3 +5,10 @@ from thefuck import logs
 def test_color():
     assert logs.color('red', Mock(no_colors=False)) == 'red'
     assert logs.color('red', Mock(no_colors=True)) == ''
+
+
+def test_debug(capsys):
+    logs.debug('test', Mock(no_colors=True, debug=True))
+    assert capsys.readouterr() == ('', 'DEBUG: test\n')
+    logs.debug('test', Mock(no_colors=True, debug=False))
+    assert capsys.readouterr() == ('', '')

tests/test_main.py

@@ -110,7 +110,7 @@ class TestGetMatchedRule(object):
     def test_when_rule_failed(self, capsys):
         main.get_matched_rule(
             Command('ls'), [Rule('test', Mock(side_effect=OSError('Denied')))],
-            Mock(no_colors=True))
+            Mock(no_colors=True, debug=False))
         assert capsys.readouterr()[1].split('\n')[0] == '[WARN] Rule test:'
 
 
@@ -126,7 +126,7 @@ class TestRunRule(object):
 
     def test_run_rule_with_side_effect(self, capsys):
         side_effect = Mock()
-        settings = Mock()
+        settings = Mock(debug=False)
         command = Command()
         main.run_rule(Rule(get_new_command=lambda *_: 'new-command',
                            side_effect=side_effect),

thefuck/conf.py

@@ -29,13 +29,15 @@ DEFAULT_SETTINGS = {'rules': DEFAULT_RULES,
                     'wait_command': 3,
                     'require_confirmation': False,
                     'no_colors': False,
+                    'debug': False,
                     'priority': {}}
 
 ENV_TO_ATTR = {'THEFUCK_RULES': 'rules',
                'THEFUCK_WAIT_COMMAND': 'wait_command',
                'THEFUCK_REQUIRE_CONFIRMATION': 'require_confirmation',
                'THEFUCK_NO_COLORS': 'no_colors',
-               'THEFUCK_PRIORITY': 'priority'}
+               'THEFUCK_PRIORITY': 'priority',
+               'THEFUCK_DEBUG': 'debug'}
 
 
 SETTINGS_HEADER = u"""# ~/.thefuck/settings.py: The Fuck settings file
@@ -87,7 +89,7 @@ def _val_from_env(env, attr):
         return dict(_priority_from_env(val))
     elif attr == 'wait_command':
         return int(val)
-    elif attr in ('require_confirmation', 'no_colors'):
+    elif attr in ('require_confirmation', 'no_colors', 'debug'):
         return val.lower() == 'true'
     else:
         return val

thefuck/logs.py

@@ -1,3 +1,4 @@
+from pprint import pformat
 import sys
 from traceback import format_exception
 import colorama
@@ -52,3 +53,12 @@ def failed(msg, settings):
         msg=msg,
         red=color(colorama.Fore.RED, settings),
         reset=color(colorama.Style.RESET_ALL, settings)))
+
+
+def debug(msg, settings):
+    if settings.debug:
+        sys.stderr.write(u'{blue}{bold}DEBUG:{reset} {msg}\n'.format(
+            msg=msg,
+            reset=color(colorama.Style.RESET_ALL, settings),
+            blue=color(colorama.Fore.BLUE, settings),
+            bold=color(colorama.Style.BRIGHT, settings)))

thefuck/main.py

@@ -1,6 +1,7 @@
 from imp import load_source
 from pathlib import Path
 from os.path import expanduser
+from pprint import pformat
 from subprocess import Popen, PIPE
 import os
 import sys
@@ -79,6 +80,7 @@ def get_command(settings, args):
         return
 
     script = shells.from_shell(script)
+    logs.debug('Call: {}'.format(script), settings)
     result = Popen(script, shell=True, stdout=PIPE, stderr=PIPE,
                    env=dict(os.environ, LANG='C'))
     if wait_output(settings, result):
@@ -90,6 +92,7 @@ def get_matched_rule(command, rules, settings):
     """Returns first matched rule for command."""
     for rule in rules:
         try:
+            logs.debug(u'Trying rule: {}'.format(rule.name), settings)
             if rule.match(command, settings):
                 return rule
         except Exception:
@@ -125,12 +128,21 @@ def main():
     colorama.init()
     user_dir = setup_user_dir()
     settings = conf.get_settings(user_dir)
+    logs.debug('Run with settings: {}'.format(pformat(settings)), settings)
 
     command = get_command(settings, sys.argv)
     if command:
+        logs.debug('Received stdout: {}'.format(command.stdout), settings)
+        logs.debug('Received stderr: {}'.format(command.stderr), settings)
+
         rules = get_rules(user_dir, settings)
+        logs.debug(
+            'Loaded rules: {}'.format(', '.join(rule.name for rule in rules)),
+            settings)
+
         matched_rule = get_matched_rule(command, rules, settings)
         if matched_rule:
+            logs.debug('Matched rule: {}'.format(matched_rule.name), settings)
             run_rule(matched_rule, command, settings)
             return