PYTHON-981 - Apply collection-level read concern to *_map_reduce and aggregate when appropriate.

Luke Lovett · behackett · commit 393ed35866fd · 2015-11-18T14:17:56.000-08:00
diff --git a/pymongo/collection.py b/pymongo/collection.py
@@ -1642,8 +1642,18 @@ def aggregate(self, pipeline, **kwargs):
 
             cmd.update(kwargs)
 
-            result = self._command(sock_info, cmd, slave_ok,
-                                   read_concern=self.read_concern)
+            # Apply this Collection's read concern if $out is not in the
+            # pipeline.
+            if sock_info.max_wire_version >= 4 and 'readConcern' not in cmd:
+                for stage in cmd['pipeline']:
+                    if '$out' in stage:
+                        result = self._command(sock_info, cmd, slave_ok)
+                        break
+                else:
+                    result = self._command(sock_info, cmd, slave_ok,
+                                           read_concern=self.read_concern)
+            else:
+                result = self._command(sock_info, cmd, slave_ok)
 
             if "cursor" in result:
                 cursor = result["cursor"]
@@ -1826,8 +1836,14 @@ def map_reduce(self, map, reduce, out, full_response=False, **kwargs):
         cmd.update(kwargs)
 
         with self._socket_for_primary_reads() as (sock_info, slave_ok):
-            response = self._command(
-                sock_info, cmd, slave_ok, ReadPreference.PRIMARY)
+            if (sock_info.max_wire_version >= 4 and 'readConcern' not in cmd and
+                    'inline' in cmd['out']):
+                response = self._command(
+                    sock_info, cmd, slave_ok, ReadPreference.PRIMARY,
+                    read_concern=self.read_concern)
+            else:
+                response = self._command(
+                    sock_info, cmd, slave_ok, ReadPreference.PRIMARY)
 
         if full_response or not response.get('result'):
             return response
@@ -1869,6 +1885,11 @@ def inline_map_reduce(self, map, reduce, full_response=False, **kwargs):
                    ("out", {"inline": 1})])
         cmd.update(kwargs)
         with self._socket_for_reads() as (sock_info, slave_ok):
+            if sock_info.max_wire_version >= 4 and 'readConcern' not in cmd:
+                res = self._command(sock_info, cmd, slave_ok,
+                                    read_concern=self.read_concern)
+            else:
+                res = self._command(sock_info, cmd, slave_ok)
             res = self._command(sock_info, cmd, slave_ok)
 
         if full_response:
diff --git a/test/test_read_concern.py b/test/test_read_concern.py
@@ -18,7 +18,7 @@
 
 from bson.son import SON
 from pymongo import monitoring
-from pymongo.errors import ConfigurationError
+from pymongo.errors import ConfigurationError, OperationFailure
 from pymongo.read_concern import ReadConcern
 
 from test import client_context, pair, unittest
@@ -110,3 +110,54 @@ def test_command_cursor(self):
         self.assertEqual(
             {'level': 'local'},
             self.listener.results['started'][0].command['readConcern'])
+
+    def test_aggregate_out(self):
+        coll = self.db.get_collection('coll', read_concern=ReadConcern('local'))
+        try:
+            tuple(coll.aggregate([{'$match': {'field': 'value'}},
+                                  {'$out': 'output_collection'}]))
+        except OperationFailure:
+            # "ns doesn't exist"
+            pass
+        self.assertNotIn('readConcern',
+                         self.listener.results['started'][0].command)
+
+    def test_map_reduce_out(self):
+        coll = self.db.get_collection('coll', read_concern=ReadConcern('local'))
+        try:
+            tuple(coll.map_reduce('function() { emit(this._id, this.value); }',
+                                  'function(key, values) { return 42; }',
+                                  out='output_collection'))
+        except OperationFailure:
+            # "ns doesn't exist"
+            pass
+        self.assertNotIn('readConcern',
+                         self.listener.results['started'][0].command)
+
+        if client_context.version.at_least(3, 1, 9, -1):
+            self.listener.results.clear()
+            try:
+                tuple(coll.map_reduce(
+                    'function() { emit(this._id, this.value); }',
+                    'function(key, values) { return 42; }',
+                    out={'inline': 1}))
+            except OperationFailure:
+                # "ns doesn't exist"
+                pass
+            self.assertEqual(
+                {'level': 'local'},
+                self.listener.results['started'][0].command['readConcern'])
+
+    @client_context.require_version_min(3, 1, 9, -1)
+    def test_inline_map_reduce(self):
+        coll = self.db.get_collection('coll', read_concern=ReadConcern('local'))
+        try:
+            tuple(coll.inline_map_reduce(
+                'function() { emit(this._id, this.value); }',
+                'function(key, values) { return 42; }'))
+        except OperationFailure:
+            # "ns doesn't exist"
+            pass
+        self.assertEqual(
+            {'level': 'local'},
+            self.listener.results['started'][0].command['readConcern'])
