LogDog: Implement RegisterPrefix RPC.

common/api/logdog_coordinator/registration/v1/service.proto

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 syntax = "proto3";
 
 package logdog;
 
 import "google/protobuf/duration.proto";
 
 // RegisterPrefixRequest registers a new Prefix with the Coordinator.
 message RegisterPrefixRequest {
   // The log stream's project.
   string project = 1;
+
+  // The log stream prefix to register.
+  string prefix = 2;
+
   // Optional information about the registering agent.
-  repeated string source_info = 2;
-
-  // The protobuf version string for this stream.
-  string proto_version = 3;
-  // The serialized LogStreamDescriptor protobuf for this stream. The stream's
-  // path is extracted from this field.
-  bytes desc = 4;
+  repeated string source_info = 3;
 
   // The prefix expiration time. If <= 0, the project's default prefix
   // expiration period will be applied.
   //
   // The prefix will be closed by the Coordinator after its expiration period.
   // Once closed, new stream registration requests will no longer be accepted.
   //
   // If supplied, this value should exceed the timeout of the local task, else
   // some of the task's streams may be dropped due to failing registration.
-  google.protobuf.Duration expiration = 5;
+  google.protobuf.Duration expiration = 10;
 }
 
 // The response message for the RegisterPrefix RPC.
 message RegisterPrefixResponse {
   // Secret is the prefix's secret. This must be included verbatim in Butler
   // bundles to assert ownership of this prefix.
   bytes secret = 1;
 
   // The name of the Pub/Sub topic to publish butlerproto-formatted Butler log
   // bundles to.
@@ skipping 10 matching lines @@
   //
   // This should be called by a Butler instance to gain the ability to publish
   // to a prefix space. The caller must have WRITE access to its project's
   // stream space. If WRITE access is not present, this will fail with the
   // "PermissionDenied" gRPC code.
   //
   // A stream prefix may be registered at most once. Additional registration
   // requests will fail with the "AlreadyExists" gRPC code.
   rpc RegisterPrefix(RegisterPrefixRequest) returns (RegisterPrefixResponse);
 }