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pool_role_shared.ml
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pool_role_shared.ml
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(*
* Copyright (C) Citrix Systems Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation; version 2.1 only. with the special
* exception on linking described in file LICENSE.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*)
(**
* @group Pool Management
*)
open Stringext
open Threadext
(** The role of this node *)
type t =
| Master
| Slave of string (* IP address *)
| Broken
let role = ref None
let role_m = Mutex.create ()
let string_of = function
| Master -> "master"
| Slave x -> "slave:" ^ x
| Broken -> "broken"
let read_pool_role () =
try
let s = String.strip String.isspace
(Unixext.string_of_file Constants.pool_config_file) in
match String.split ~limit:2 ':' s with
| [ "master" ] -> Master
| [ "slave"; m_ip ] -> Slave m_ip
| [ "broken" ] -> Broken
| _ -> failwith "cannot parse pool_role from pool config file"
with _ -> Broken
let get_role () =
Mutex.execute role_m (fun _ ->
match !role with
| Some x -> x
| None ->
let r = read_pool_role () in
role := Some r;
r
)
let is_master () = get_role () = Master
let is_slave () = match get_role () with
| Slave _ -> true
| _ -> false
let is_broken () = get_role () = Broken
exception This_host_is_a_master
exception This_host_is_broken
let get_master_address () = match get_role () with
| Slave ip -> ip
| Master -> raise This_host_is_a_master
| Broken -> raise This_host_is_broken