Health check doesn't implement grpc health protocol

[eugkhp]

I'm trying to use health check #626 feature. But I can't figure out a way to check service status.
I'm using https://github.com/grpc-ecosystem/grpc-health-probe/ cli program, but and when I run it, it says:

/grpc_health_probe-linux-amd64 --addr=0.0.0.0:50051 -v
parsed options:
> addr=0.0.0.0:50051 conn_timeout=1s rpc_timeout=1s
> tls=false
establishing connection
connection established (took 229.529469ms)
error: this server does not implement the grpc health protocol (grpc.health.v1.Health)

either on my own service:

      implicit0(hc: HealthCheckServiceFS2[F]) <- HealthServiceFS2.buildInstance[F]
      healthCheck                             <- HealthCheckServiceFS2.bindService[F]

      endpoints = List(
                   ...
                    AddService(healthCheck)
                  )
      server <- GrpcServer.default[F](r.config.rpcPort, endpoints)

      _ <- info"Gateway Starting"
      _ <- List(GatewayHttpEndpoint.launch(...),
                GrpcServer.server[F](server)
           ).parTraverse_(identity)

or on example (https://github.com/higherkindness/mu-scala-examples/tree/master/health-check) server:

sbt health-server-fs2/run
[info] Loading global plugins from /home/user/.sbt/1.0/plugins
[info] Loading settings for project mu-scala-examples-build from plugins.sbt ...
[info] Loading project definition from /home/user/IdeaProjects/mu-scala-examples/project
[info] Loading settings for project root from build.sbt,version.sbt ...
[info] Resolving key references (22777 settings) ...
[info] Set current project to mu-scala-examples (in build file:/home/user/IdeaProjects/mu-scala-examples/)
[info] running higherkindness.mu.rpc.healthcheck.sFs2.ServerApp 

Am I doing something wrong? Or it doesn't support "default" healthcheck?

[eugkhp]

By the way, if I make some naive implementation like this:

class HealthSvc[F[_]: MonadError[*[_], Throwable]: Logging: Timer: Sync] extends Health[F] {
  val E = MonadError[F, Throwable]
  val L = Logging[F]

  override def Check(req: HealthCheckRequest): F[HealthCheckResponse] = {
    HealthCheckResponse(Some(ServingStatus.SERVING)).pure[F]
  }

  override def Watch(req: HealthCheck.HealthCheckRequest): F[fs2.Stream[F, HealthCheckResponse]] = {
    Sync[F].delay(
      fs2.Stream.fixedRate(5 seconds).evalMap(_ => HealthCheckResponse(Some(ServingStatus.SERVING)).pure[F])
    )
  }
} 

it works like a charm:

./grpc_health_probe-linux-amd64 --addr=0.0.0.0:50051 -v
parsed options:
> addr=0.0.0.0:50051 conn_timeout=1s rpc_timeout=1s
> tls=false
establishing connection
connection established (took 117.100079ms)
time elapsed: connect=117.100079ms rpc=50.927594ms
status: SERVING

Did I misunderstood the feature?