From 47e87df132e9cd13eeb35a4f377a14f836be0f75 Mon Sep 17 00:00:00 2001
From: benoitc <bchesneau@gmail.com>
Date: Thu, 28 Oct 2010 06:05:01 +0200
Subject: [PATCH] display the right error when a worker can't be used.

---
 gunicorn/app/base.py          | 7 ++++++-
 gunicorn/workers/geventlet.py | 6 ++++--
 gunicorn/workers/ggevent.py   | 6 ++++--
 gunicorn/workers/gtornado.py  | 5 ++++-
 4 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/gunicorn/app/base.py b/gunicorn/app/base.py
index ce9df2490..38879f07b 100644
--- a/gunicorn/app/base.py
+++ b/gunicorn/app/base.py
@@ -117,7 +117,12 @@ def run(self):
                 raise
                     
         self.configure_logging()
-        Arbiter(self).run()
+        try:
+            Arbiter(self).run()
+        except RuntimeError, e:
+            sys.stderr.write("\nError: %s\n\n" % e)
+            sys.stderr.flush()
+            sys.exit(1)
     
     def configure_logging(self):
         """\
diff --git a/gunicorn/workers/geventlet.py b/gunicorn/workers/geventlet.py
index 96e32398f..970abecea 100644
--- a/gunicorn/workers/geventlet.py
+++ b/gunicorn/workers/geventlet.py
@@ -7,8 +7,10 @@
 
 
 import os
-
-import eventlet
+try:
+    import eventlet
+except ImportError:
+    raise RuntimeError("You need eventlet installed to use this worker.")
 from eventlet import hubs
 from eventlet.greenio import GreenSocket
 
diff --git a/gunicorn/workers/ggevent.py b/gunicorn/workers/ggevent.py
index d2b61ae6a..e9e1d9fa7 100644
--- a/gunicorn/workers/ggevent.py
+++ b/gunicorn/workers/ggevent.py
@@ -12,8 +12,10 @@
 if sys.platform == "darwin":
     os.environ['EVENT_NOKQUEUE'] = "1"
 
-
-import gevent
+try:
+    import gevent
+except ImportError:
+    raise RuntimeError("You need gevent installed to use this worker.")
 from gevent.pool import Pool
 from gevent.server import StreamServer
 from gevent import pywsgi, wsgi
diff --git a/gunicorn/workers/gtornado.py b/gunicorn/workers/gtornado.py
index 2f73ad812..5bea9291f 100644
--- a/gunicorn/workers/gtornado.py
+++ b/gunicorn/workers/gtornado.py
@@ -6,7 +6,10 @@
 import os
 import sys
 
-import tornado.web
+try:
+    import tornado.web
+except ImportError:
+    raise RuntimeError("You need tornado installed to use this worker.")
 from tornado.httpserver import HTTPServer
 from tornado.ioloop import IOLoop, PeriodicCallback
 from tornado.wsgi import WSGIContainer