Include hook id in output with --verbose. Closes #88.

pre_commit/output.py

@@ -0,0 +1,66 @@
+import subprocess
+
+from pre_commit import color
+
+
+# TODO: smell: import side-effects
+COLS = int(
+    subprocess.Popen(['tput', 'cols'], stdout=subprocess.PIPE).communicate()[0]
+)
+
+
+def get_hook_message(
+    start,
+    postfix='',
+    end_msg=None,
+    end_len=0,
+    end_color=None,
+    use_color=None,
+    cols=COLS,
+):
+    """Prints a message for running a hook.
+
+    This currently supports three approaches:
+
+    # Print `start` followed by dots, leaving 6 characters at the end
+    >>> print_hook_message('start', end_len=6)
+    start...............................................................
+
+    # Print `start` followed by dots with the end message colored if coloring is
+    # specified and a newline afterwards
+    >>> print_hook_message(
+        'start',
+        end_msg='end',
+        end_color=color.RED,
+        use_color=True,
+    )
+    start...................................................................end
+
+    # Print `start` followed by dots, followed by the `postfix` message
+    # uncolored, followed by the `end_msg` colored if specified and a newline
+    # afterwards
+    >>> print_hook_message(
+        'start',
+        postfix='postfix ',
+        end_msg='end',
+        end_color=color.RED,
+        use_color=True,
+    )
+    start...........................................................postfix end
+    """
+    if bool(end_msg) == bool(end_len):
+        raise ValueError('Expected one of (`end_msg`, `end_len`)')
+    if end_msg is not None and (end_color is None or use_color is None):
+        raise ValueError(
+            '`end_color` and `use_color` are required with `end_msg`'
+        )
+
+    if end_len:
+        return start + '.' * (cols - len(start) - end_len - 1)
+    else:
+        return '{0}{1}{2}{3}\n'.format(
+            start,
+            '.' * (cols - len(start) - len(postfix) - len(end_msg) - 1),
+            postfix,
+            color.format_color(end_msg, end_color, use_color),
+        )