Support Contended Transaction Errors

fauna/client/client.py

@@ -5,7 +5,7 @@
 import fauna
 from fauna.errors import AuthenticationError, ClientError, ProtocolError, ServiceError, AuthorizationError, \
     ServiceInternalError, ServiceTimeoutError, ThrottlingError, QueryTimeoutError, QueryRuntimeError, \
-    QueryCheckError, AbortError, InvalidRequestError
+    QueryCheckError, ContendedTransactionError, AbortError, InvalidRequestError
 from fauna.client.headers import _DriverEnvironment, _Header, _Auth, Header
 from fauna.http.http_client import HTTPClient
 from fauna.query import Query, Page, fql
@@ -474,6 +474,18 @@ def _handle_error(self, body: Any, status_code: int):
           txn_ts=txn_ts,
           schema_version=schema_version,
       )
+    elif status_code == 409:
+      raise ContendedTransactionError(
+          status_code=status_code,
+          code=code,
+          message=message,
+          summary=summary,
+          constraint_failures=constraint_failures,
+          query_tags=query_tags,
+          stats=stats,
+          txn_ts=txn_ts,
+          schema_version=schema_version,
+      )
     elif status_code == 429:
       raise ThrottlingError(
           status_code=status_code,

fauna/errors/__init__.py

@@ -2,5 +2,5 @@
 from .errors import ClientError, FaunaError, NetworkError
 from .errors import ProtocolError, ServiceError
 from .errors import AuthenticationError, AuthorizationError, QueryCheckError, QueryRuntimeError, \
-    QueryTimeoutError, ServiceInternalError, ServiceTimeoutError, ThrottlingError, \
+    QueryTimeoutError, ServiceInternalError, ServiceTimeoutError, ThrottlingError, ContendedTransactionError, \
     InvalidRequestError, AbortError

fauna/errors/errors.py

@@ -136,6 +136,11 @@ class QueryCheckError(ServiceError):
   pass
 
 
+class ContendedTransactionError(ServiceError):
+  """Transaction is aborted due to concurrent modification."""
+  pass
+
+
 class QueryRuntimeError(ServiceError):
   """An error response that is the result of the query failing during execution.
     QueryRuntimeError's occur when a bug in your query causes an invalid execution