lua-resty-worker-manager
Tracks workers and nodes starting/restarting/reloading/stopping.
Status
This library is still under early development, and currently lacks tests.
Synopsis
http {
lua_shared_dict my_shm 5m;
init_by_lua_block {
require("resty.worker.manager").on_init_by_lua({
shm = "my_shm",
interval = 10, -- worker heartbeat interval in seconds
failed = 5, -- max heartbeat overrun to detect crashed worker, in seconds
},
function(master_id, n_prev, n_mine, n_next)
ngx.log(ngx.ERR, "================================= Master start =================================")
if n_prev == nil then
-- no previous master, so this is nginx start or restart
else
-- previous master, so we are reloading
if n_prev == 0 then
-- all old workers have already exited
else
-- stil 'n_prev' old workers are running
end
end
end,
function(master_id, n_prev, n_mine, n_next)
ngx.log(ngx.ERR, "================================= Master exit ==================================")
if n_next == nil then
-- we are stopping this nginx node
else
-- we are only reloading, all our workers have already exited, this code
-- runs on the last worker.
if n_next > 0 then
-- new workers have already been initialized
end
end
end)
kong = require 'kong'
kong.init()
}
init_worker_by_lua_block {
require("resty.worker.manager").on_init_worker_by_lua(
function(worker_id, n_prev, n_mine, n_next)
ngx.log(ngx.ERR, "--------------------------------- Worker start ---------------------------------")
if n_mine == 1 then
-- I'm the very first worker to start
elseif n_mine > ngx.worker.count() then
-- a worker failed and exited, this a respawned worker.
-- After the failed worker heart-beat times out then
-- n_mine == ngx.worker.count() again
else
-- other workers have started before me
end
end,
function(worker_id, n_prev, n_mine, n_next)
ngx.log(ngx.ERR, "--------------------------------- Worker exit ----------------------------------")
if n_next then
-- we are reloading nginx
end
if n_mine == 1 then
-- I'm the very last worker to exit
else
-- I'm not the last worker, there are more
end
end)
kong.init_worker()
}
}
Description
Within Nginx/OpenResty it is not always easy to detect workers starting/stopping and to distinguish between starting/restarting/reloading/stopping the server. That is what this module does. It detects those, and allows to run synchonized code (protected within a lock) when it does
See the online LDoc documentation for the complete API.
History
0.1 (xx-Nov-xx) Initial release
- Initial upload
Copyright and License
Copyright 2017 Kong Inc.
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.