Fix 500 in versioned writes with bad Destination

When this code lived in the proxy, it was protected by an "except
HTTPException" clause in proxy.Application.handle_request(). When it
moved to middleware, it lost that, and then things like
constraints.check_name_format that raised HTTPException would cause
500s. The HTTPException would make it all the way out to catch_errors
and get translated to a 500.

This commit just wraps a couple try/excepts around the bits in
versioned writes that can raise HTTPException. I tried to make it use
wsgify so I could get that for free, but that wound up being a real
pain because env/start_response are plumbed through pretty much the
whole versioned-writes middleware.

Closes-Bug: 1483705

Change-Id: Ife165bf709e64f313ed07c779b21914045e51f25

swift/common/middleware/versioned_writes.py

@@ -119,7 +119,7 @@
     register_swift_info, config_true_value
 from swift.common.request_helpers import get_sys_meta_prefix
 from swift.common.wsgi import WSGIContext, make_pre_authed_request
-from swift.common.swob import Request
+from swift.common.swob import Request, HTTPException
 from swift.common.constraints import (
     check_account_format, check_container_format, check_destination_header)
 from swift.proxy.controllers.base import get_container_info
@@ -468,12 +468,18 @@ def __call__(self, env, start_response):
         # container_info
         allow_versioned_writes = self.conf.get('allow_versioned_writes')
         if allow_versioned_writes and container and not obj:
-            return self.container_request(req, start_response,
-                                          allow_versioned_writes)
+            try:
+                return self.container_request(req, start_response,
+                                              allow_versioned_writes)
+            except HTTPException as error_response:
+                return error_response(env, start_response)
         elif obj and req.method in ('PUT', 'COPY', 'DELETE'):
-            return self.object_request(
-                req, version, account, container, obj,
-                allow_versioned_writes)(env, start_response)
+            try:
+                return self.object_request(
+                    req, version, account, container, obj,
+                    allow_versioned_writes)(env, start_response)
+            except HTTPException as error_response:
+                return error_response(env, start_response)
         else:
             return self.app(env, start_response)
 

test/unit/common/middleware/test_versioned_writes.py

@@ -108,11 +108,8 @@ def test_container_allow_versioned_writes_false(self):
             req = Request.blank('/v1/a/c',
                                 headers={'X-Versions-Location': 'ver_cont'},
                                 environ={'REQUEST_METHOD': method})
-            try:
-                status, headers, body = self.call_vw(req)
-            except swob.HTTPException as e:
-                pass
-            self.assertEquals(e.status_int, 412)
+            status, headers, body = self.call_vw(req)
+            self.assertEquals(status, "412 Precondition Failed")
 
         # GET/HEAD performs as normal
         self.app.register('GET', '/v1/a/c', swob.HTTPOk, {}, 'passed')
@@ -414,6 +411,17 @@ def test_copy_new_version_different_account(self):
         self.assertEqual(len(self.authorized), 1)
         self.assertRequestEqual(req, self.authorized[0])
 
+    def test_copy_new_version_bogus_account(self):
+        cache = FakeCache({'sysmeta': {'versions-location': 'ver_cont'}})
+        req = Request.blank(
+            '/v1/src_a/src_cont/src_obj',
+            environ={'REQUEST_METHOD': 'COPY', 'swift.cache': cache,
+                     'CONTENT_LENGTH': '100'},
+            headers={'Destination': 'tgt_cont/tgt_obj',
+                     'Destination-Account': '/im/on/a/boat'})
+        status, headers, body = self.call_vw(req)
+        self.assertEquals(status, '412 Precondition Failed')
+
     def test_delete_first_object_success(self):
         self.app.register(
             'DELETE', '/v1/a/c/o', swob.HTTPOk, {}, 'passed')