Specs

call(
  pool :: atom(),
  request :: atom(),
  args :: list(),
  timeout :: timeout(),
  retry :: pos_integer(),
  retry_sleep :: non_neg_integer()
) :: term() | {:error_rpc, reason :: term()}

Makes a synchronous RPC call request using workers pool and waits for reply.

If successful, call/6 returns Kernel.apply(RpcServerMod, request, args) evaluation result on remote server.

If error occurs during request processing {:error_rpc, reason} is returned.

User defined RPC server functions should not return results as tuples with first tuple element being :error_rpc or any atom name starting with :error_rpc (for example :error_rpc_remote) as those tuples are reserved by MeshxRpc internally for error reporting and processing.

Possible request processing errors:

• :full - all client pool workers are busy and pool manager cannot checkout new worker,
• :killed - process executing request on remote server was killed because function execution time exceeded allowed timeout (see MeshxRpc.Server.Pool option :timeout_execute),
• :invalid_cks - checksum check with user provided checksum function (:cks_mfa option) failed,
• :timeout_cks - checksum calculation timeout,
• :closed - client worker received user request before handshake with server was completed,
• :tcp_closed - TCP socket connection was closed,
• :invalid_ref - request message failed referential integrity check,
• {:undef, [...]} - request function not defined on server,
• :invalid_state - server or client worker encountered inconsistent critical state,
• any :inet POSIX Error Codes,
• any errors from (de)serialization function.

If remote server does not respond within time specified by timeout argument, process executing RPC call is killed, the function call fails and the caller exits. Additionally connection to remote server is closed which kills corresponding RPC call process being executed on the server. Please be aware of MeshxRpc.Server.Pool :timeout_execute configuration option playing similar role to timeout function argument on the server side.

If error occurs during request processing and error reason is in list defined by :exec_retry_on_error configuration option, request will be retried retry times with randomized exponential back-off starting with retry_sleep msec.

Example:

iex(1)> MeshxRpc.Client.Pool.call(Example1.Client, :echo, "hello world")
"hello world"
iex(2)> MeshxRpc.Client.Pool.call(Example1.Client, :not_existing, "hello world")
{:error_rpc, {:undef,  [...]}}

Specs

call!(
  pool :: atom(),
  request :: atom(),
  args :: list(),
  timeout :: timeout(),
  retry :: pos_integer(),
  retry_sleep :: non_neg_integer()
) :: term() | {:error_rpc, reason :: term()}

Same as call/6, will reraise remote exception locally.

Example:

iex(1)> MeshxRpc.Client.Pool.call(Example1.Client, :raise_test, "raise kaboom!")
{:error_rpc, %RuntimeError{message: "raise kaboom!"}}
iex(2)> MeshxRpc.Client.Pool.call!(Example1.Client, :raise_test, "raise kaboom!")
** (RuntimeError) raise kaboom!

Specs

cast(
  pool :: atom(),
  request :: atom(),
  args :: list(),
  timeout :: timeout(),
  retry :: pos_integer(),
  retry_sleep :: non_neg_integer()
) :: :ok

Sends an asynchronous RPC cast request using workers pool.

Function always immediately returns :ok, even if pool doesn't exist or any other error takes place.

args, timeout, retry and retry_sleep function arguments have the same meaning as in case of call/6.

Example:

iex(1)> MeshxRpc.Client.Pool.cast(NotExisting, :undefined, [])
:ok

Specs

child_spec(id :: atom() | String.t(), opts :: Keyword.t()) ::
  :supervisor.child_spec()

Returns a specification to start a RPC client workers pool under a supervisor.

id is a pool id which might be a name of a module implementing user RPC functions.

opts are options described in "Configuration" section above and in MeshxRpc "Common configuration" section.

Example:

iex(1)> MeshxRpc.Client.Pool.child_spec(Example1.Client, address: {:uds, "/tmp/meshx.sock"})
{Example1.Client,
 {:poolboy, :start_link,
  [
    [
      name: {:local, Example1.Client},
      worker_module: MeshxRpc.Client.Worker
    ],
    [
      ...
    ]
  ]}, :permanent, 5000, :worker, [:poolboy]}