Add morphlib.Error and make local repo cache exceptions be based on it

This way, cliapp will automatically print an error message, rather
than a stack trace.

2 files changed, 11 insertions, 2 deletions

diff --git a/morphlib/__init__.py b/morphlib/__init__.py
index d110296d..121c9431 100644
--- a/morphlib/__init__.py
+++ b/morphlib/__init__.py
@@ -17,6 +17,14 @@
 '''Baserock library.'''
 
 
+import cliapp
+
+
+class Error(cliapp.AppException):
+
+    '''Base for all morph exceptions that cause user-visible messages.'''
+
+
 import artifact
 import artifactresolver
 import bins
diff --git a/morphlib/localrepocache.py b/morphlib/localrepocache.py
index 5e04b187..b8dfea88 100644
--- a/morphlib/localrepocache.py
+++ b/morphlib/localrepocache.py
@@ -34,7 +34,7 @@ urlparse.uses_fragment.extend(gitscheme)
 
 
 
-class NoRemote(Exception):
+class NoRemote(morphlib.Error):
 
     def __init__(self, reponame, errors):
         self.reponame = reponame
@@ -44,13 +44,14 @@ class NoRemote(Exception):
         return '\n\t'.join(['Cannot find remote git repository: %s' %
                             self.reponame] + self.errors)
 
-class NotCached(Exception):
+class NotCached(morphlib.Error):
     def __init__(self, reponame):
         self.reponame = reponame
 
     def __str__(self): # pragma: no cover
         return 'Repository %s is not cached yet' % self.reponame
 
+
 class LocalRepoCache(object):
 
     '''Manage locally cached git repositories.