PYTHON-1409 - Improve server compatibility error messages

Author: behackett

pymongo/common.py

@@ -48,6 +48,7 @@
 MAX_WRITE_BATCH_SIZE = 1000
 
 # What this version of PyMongo supports.
+MIN_SUPPORTED_SERVER_VERSION = "2.6"
 MIN_SUPPORTED_WIRE_VERSION = 2
 MAX_SUPPORTED_WIRE_VERSION = 5
 

pymongo/topology_description.py

@@ -76,15 +76,21 @@ def __init__(self,
  s.max_wire_version is not None
  and s.max_wire_version < common.MIN_SUPPORTED_WIRE_VERSION)
 
- if server_too_new or server_too_old:
+ if server_too_new:
  self._incompatible_err = (
- "Server at %s:%d "
- "uses wire protocol versions %d through %d, "
- "but PyMongo only supports %d through %d"
+ "Server at %s:%d requires wire version %d, but this "
+ "version of PyMongo only supports up to %d."
  % (s.address[0], s.address[1],
- s.min_wire_version, s.max_wire_version,
+ s.min_wire_version, common.MAX_SUPPORTED_WIRE_VERSION))
+
+ elif server_too_old:
+ self._incompatible_err = (
+ "Server at %s:%d reports wire version %d, but this "
+ "version of PyMongo requires at least %d (MongoDB %s)."
+ % (s.address[0], s.address[1],
+ s.max_wire_version,
  common.MIN_SUPPORTED_WIRE_VERSION,
- common.MAX_SUPPORTED_WIRE_VERSION))
+ common.MIN_SUPPORTED_SERVER_VERSION))
 
  break
 

test/test_topology.py

@@ -567,8 +567,33 @@ def test_wire_version(self):
  t.select_servers(any_server_selector)
  except ConfigurationError as e:
  # Error message should say which server failed and why.
- self.assertTrue('a:27017' in str(e))
- self.assertTrue('wire protocol versions 11 through 12' in str(e))
+ self.assertEqual(
+ str(e),
+ "Server at a:27017 requires wire version 11, but this version "
+ "of PyMongo only supports up to %d."
+ % (common.MAX_SUPPORTED_WIRE_VERSION,))
+ else:
+ self.fail('No error with incompatible wire version')
+
+ # Incompatible.
+ got_ismaster(t, address, {
+ 'ok': 1,
+ 'ismaster': True,
+ 'setName': 'rs',
+ 'hosts': ['a'],
+ 'minWireVersion': 0,
+ 'maxWireVersion': 0})
+
+ try:
+ t.select_servers(any_server_selector)
+ except ConfigurationError as e:
+ # Error message should say which server failed and why.
+ self.assertEqual(
+ str(e),
+ "Server at a:27017 reports wire version 0, but this version "
+ "of PyMongo requires at least %d (MongoDB %s)."
+ % (common.MIN_SUPPORTED_WIRE_VERSION,
+ common.MIN_SUPPORTED_SERVER_VERSION))
  else:
  self.fail('No error with incompatible wire version')