1 files changed, 44 insertions, 0 deletions
diff --git a/gbp/format.py b/gbp/format.py
new file mode 100644
index 00000000..2a4af15c
--- /dev/null
+++ b/gbp/format.py
@@ -0,0 +1,44 @@
+# vim: set fileencoding=utf-8 :
+#
+# (C) 2014 Guido Guenther <agx@sigxcpu.org>
+#    This program is free software; you can redistribute it and/or modify
+#    it under the terms of the GNU General Public License as published by
+#    the Free Software Foundation; either version 2 of the License, or
+#    (at your option) any later version.
+#
+#    This program is distributed in the hope that it will be useful,
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#    GNU General Public License for more details.
+#
+#    You should have received a copy of the GNU General Public License
+#    along with this program; if not, write to the Free Software
+#    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+"""Format a message"""
+
+from gbp.errors import GbpError
+
+def format_msg(msg, args):
+    """
+    Format a strin with the given dict. Be a bit more verbose than
+    default python about the error cause.
+
+    >>> format_msg("%(foo)", {})
+    Traceback (most recent call last):
+    ...
+    GbpError: Failed to format %(foo): Missing value 'foo' in {}
+    >>> format_msg("%(foo)", {'foo': 'bar'})
+    Traceback (most recent call last):
+    ...
+    GbpError: Failed to format %(foo) with {'foo': 'bar'}: incomplete format
+    >>> format_msg("A %(foo)s is a %(bar)s", {'foo': 'dog', 'bar': 'mamal'})
+    'A dog is a mamal'
+    """
+    try:
+        return msg % args
+    except ValueError as e:
+        raise GbpError("Failed to format %s with %s: %s" % (msg, args, e))
+    except KeyError as e:
+            raise GbpError("Failed to format %s: Missing value %s in %s" % (msg, e, args))
+
+