Re-enable stacktracing when --debug is used

Commit 1f89beb6098f4f6a8d8c2912392b273bc068b2e3 introduced the behaviour
that a stacktrace is printed if an exception is encountered.

This helped make the client more supportable:

 $ glance --debug image-list
  .
  .
  .
  File "glanceclient/common/http.py", line 337, in get_http_client
    xxx
 NameError: global name 'xxx' is not defined
 global name 'xxx' is not defined

The behaviour was lost at some point. This patch re-enables it.

Change-Id: I25fc8624797909d606590747f54b9cf649ade079
Closes-bug: 1563830

glanceclient/common/utils.py

@@ -467,6 +467,14 @@ def endpoint_version_from_url(endpoint, default_version=None):
         return None, default_version
 
 
+def debug_enabled(argv):
+    if bool(env('GLANCECLIENT_DEBUG')) is True:
+        return True
+    if '--debug' in argv or '-d' in argv:
+        return True
+    return False
+
+
 class IterableWithLength(object):
     def __init__(self, iterable, length):
         self.iterable = iterable

glanceclient/shell.py

@@ -489,18 +489,12 @@ class OpenStackImagesShell(object):
             try:
                 return self.get_subcommand_parser(api_version)
             except ImportError as e:
-                if options.debug:
-                    traceback.print_exc()
                 if not str(e):
                     # Add a generic import error message if the raised
                     # ImportError has none.
                     raise ImportError('Unable to import module. Re-run '
                                       'with --debug for more info.')
                 raise
-            except Exception:
-                if options.debug:
-                    traceback.print_exc()
-                raise
 
         # Parse args once to find version
 
@@ -595,12 +589,6 @@ class OpenStackImagesShell(object):
             args.func(client, args)
         except exc.Unauthorized:
             raise exc.CommandError("Invalid OpenStack Identity credentials.")
-        except Exception:
-            # NOTE(kragniz) Print any exceptions raised to stderr if the
-            # --debug flag is set
-            if args.debug:
-                traceback.print_exc()
-            raise
         finally:
             if profile:
                 trace_id = osprofiler_profiler.get().get_base_id()
@@ -671,4 +659,6 @@ def main():
     except KeyboardInterrupt:
         utils.exit('... terminating glance client', exit_code=130)
     except Exception as e:
+        if utils.debug_enabled(argv) is True:
+            traceback.print_exc()
         utils.exit(encodeutils.exception_to_unicode(e))

glanceclient/tests/unit/test_shell.py

@@ -22,6 +22,7 @@ except ImportError:
 import hashlib
 import os
 import sys
+import traceback
 import uuid
 
 import fixtures
@@ -150,6 +151,44 @@ class ShellTest(testutils.TestCase):
         argstr = '--os-image-api-version 2 help foofoo'
         self.assertRaises(exc.CommandError, shell.main, argstr.split())
 
+    @mock.patch('sys.stdout', six.StringIO())
+    @mock.patch('sys.stderr', six.StringIO())
+    @mock.patch('sys.argv', ['glance', 'help', 'foofoo'])
+    def test_no_stacktrace_when_debug_disabled(self):
+        with mock.patch.object(traceback, 'print_exc') as mock_print_exc:
+            try:
+                openstack_shell.main()
+            except SystemExit:
+                pass
+            self.assertFalse(mock_print_exc.called)
+
+    @mock.patch('sys.stdout', six.StringIO())
+    @mock.patch('sys.stderr', six.StringIO())
+    @mock.patch('sys.argv', ['glance', 'help', 'foofoo'])
+    def test_stacktrace_when_debug_enabled_by_env(self):
+        old_environment = os.environ.copy()
+        os.environ = {'GLANCECLIENT_DEBUG': '1'}
+        try:
+            with mock.patch.object(traceback, 'print_exc') as mock_print_exc:
+                try:
+                    openstack_shell.main()
+                except SystemExit:
+                    pass
+                self.assertTrue(mock_print_exc.called)
+        finally:
+            os.environ = old_environment
+
+    @mock.patch('sys.stdout', six.StringIO())
+    @mock.patch('sys.stderr', six.StringIO())
+    @mock.patch('sys.argv', ['glance', '--debug', 'help', 'foofoo'])
+    def test_stacktrace_when_debug_enabled(self):
+        with mock.patch.object(traceback, 'print_exc') as mock_print_exc:
+            try:
+                openstack_shell.main()
+            except SystemExit:
+                pass
+            self.assertTrue(mock_print_exc.called)
+
     def test_help(self):
         shell = openstack_shell.OpenStackImagesShell()
         argstr = '--os-image-api-version 2 help'