[VISUALIZER] Extract health proto into shared directory (blockscout#893)

* Update integration tests to use launcher 'init_server' for server initialization

* Add integration test for health endpoint

* Extract health proto definition into shared directory

* Add proto into docker build contexts

Author: rimrakhimov

.github/workflows/visualizer.yml

@@ -146,6 +146,8 @@ jobs:
         with:
           context: "visualizer"
           file: "visualizer/Dockerfile"
+          build-contexts: |
+            proto=proto
           push: ${{ steps.tags_extractor.outputs.tags != '' }}
           tags: ${{ steps.tags_extractor.outputs.tags }}
           # platforms: |

proto/health/v1/health.proto

@@ -0,0 +1,73 @@
+// Copyright 2015 The gRPC Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// The canonical version of this proto can be found at
+// https://github.com/grpc/grpc-proto/blob/master/grpc/health/v1/health.proto
+
+syntax = "proto3";
+
+package grpc.health.v1;
+
+option csharp_namespace = "Grpc.Health.V1";
+option go_package = "google.golang.org/grpc/health/grpc_health_v1";
+option java_multiple_files = true;
+option java_outer_classname = "HealthProto";
+option java_package = "io.grpc.health.v1";
+
+message HealthCheckRequest {
+  string service = 1;
+}
+
+message HealthCheckResponse {
+  enum ServingStatus {
+    UNKNOWN = 0;
+    SERVING = 1;
+    NOT_SERVING = 2;
+    SERVICE_UNKNOWN = 3;  // Used only by the Watch method.
+  }
+  ServingStatus status = 1;
+}
+
+// Health is gRPC's mechanism for checking whether a server is able to handle
+// RPCs. Its semantics are documented in
+// https://github.com/grpc/grpc/blob/master/doc/health-checking.md.
+service Health {
+  // Check gets the health of the specified service. If the requested service
+  // is unknown, the call will fail with status NOT_FOUND. If the caller does
+  // not specify a service name, the server should respond with its overall
+  // health status.
+  //
+  // Clients should set a deadline when calling Check, and can declare the
+  // server unhealthy if they do not receive a timely response.
+  //
+  // Check implementations should be idempotent and side effect free.
+  rpc Check(HealthCheckRequest) returns (HealthCheckResponse);
+
+  // Performs a watch for the serving status of the requested service.
+  // The server will immediately send back a message indicating the current
+  // serving status.  It will then subsequently send a new message whenever
+  // the service's serving status changes.
+  //
+  // If the requested service is unknown when the call is received, the
+  // server will send a message setting the serving status to
+  // SERVICE_UNKNOWN but will *not* terminate the call.  If at some
+  // future point, the serving status of the service becomes known, the
+  // server will send a new message with the service's serving status.
+  //
+  // If the call terminates with status UNIMPLEMENTED, then clients
+  // should assume this method is not supported and should not retry the
+  // call.  If the call terminates with any other status (including OK),
+  // clients should retry the call with appropriate exponential backoff.
+//  rpc Watch(HealthCheckRequest) returns (stream HealthCheckResponse);
+}