feat(shard-distributor): Add canary pinger for periodic shard ownership verification

proto/internal/uber/cadence/sharddistributor/v1/canary.proto

@@ -0,0 +1,42 @@
+// Copyright (c) 2020 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+syntax = "proto3";
+
+package uber.cadence.sharddistributor.v1;
+
+option go_package = "github.com/uber/cadence/.gen/proto/sharddistributor/v1;sharddistributorv1";
+
+// ShardDistributorExecutorCanaryAPI is used for canary testing executor-to-executor communication
+service ShardDistributorExecutorCanaryAPI {
+  // Ping allows one executor to ping another executor that owns a specific shard
+  rpc Ping(PingRequest) returns (PingResponse);
+}
+
+message PingRequest {
+  string shard_key = 1;
+  string namespace = 2;
+}
+
+message PingResponse {
+  string executor_id = 1;
+  bool owns_shard = 2;
+  string shard_key = 3;
+}