Release 1.8.0

Please see the notes for the previous releases here: https://github.com/grpc/grpc/releases. Also please see https://grpc.io/ for all information regarding this product.

This is the 1.8.0 release of gRPC.

General

• The third_party/protobuf submodule has been upgraded to 3.5.0, which results in the 1.8.0 tools packages across languages to generate code that should be used with Protocol Buffers 3.5.0. Protocol Buffers 3.5.0 has a subtle breaking change in how it deals with unknown fields, which used to by default discarded when using proto3 syntax, are now preserved unless explicitly discarded by calling the respective API in each language.

C-core

• Several LB policies fixes (grpclb and pick_first).
• Made backoff code comply with the spec (#13121)
• Fixed subchannel sharing (#12767)
• Assorted bugfixes: (#13036, #13119, #13256)

Python

• More strict enforcement of type-correctness of metadata values. (#13672)
• Experimental support for client and server interceptors. (#13722)
• Introduces ServicerContext.abort for terminating RPCs with non-OK status. (#13667)
• grpcio Python package now depends on protobuf 3.5.0, which includes the behavior change explained above in the general section. To discard unknown fields, use message.DiscardUnknownFields() in protobuf Python API.

Ruby

• Bug fixes

C#

• Performance: Several changes to reduce stress on GC (#13439, #13444, #13459, #13462, #13475)

Objective-C

• gRPC Objective-C now invokes grpc_init() at class initialization time instead of load time (#13261)
• Fixed an issue in Objective C protobuf forward declaration (#13437)
• Fixed an issue that causes battery drain (#13435)