mod_posix: Move everything to util.startup
This allows greater control over the order of events.
Notably, the internal ordering between daemonization, initialization of
libunbound and setup of signal handling is sensitive.
libunbound starts a separate thread for processing DNS requests.
If this thread is started before signal handling has been set up, it
will not inherit the signal handlers and instead behave as it would have
before signal handlers were set up, i.e. cause the whole process to
immediately exit.
libunbound is usually initialized on the first DNS request, usually
triggered by an outgoing s2s connection attempt.
If daemonization happens before signals have been set up, signals may
not be processed at all.
local events = require "prosody.util.events";
local fsm_methods = {};
local fsm_mt = { __index = fsm_methods };
local function is_fsm(o)
local mt = getmetatable(o);
return mt == fsm_mt;
end
local function notify_transition(fire_event, transition_event)
local ret;
ret = fire_event("transition", transition_event);
if ret ~= nil then return ret; end
if transition_event.from ~= transition_event.to then
ret = fire_event("leave/"..transition_event.from, transition_event);
if ret ~= nil then return ret; end
end
ret = fire_event("transition/"..transition_event.name, transition_event);
if ret ~= nil then return ret; end
end
local function notify_transitioned(fire_event, transition_event)
if transition_event.to ~= transition_event.from then
fire_event("enter/"..transition_event.to, transition_event);
end
if transition_event.name then
fire_event("transitioned/"..transition_event.name, transition_event);
end
fire_event("transitioned", transition_event);
end
local function do_transition(name)
return function (self, attr)
local new_state = self.fsm.states[self.state][name] or self.fsm.states["*"][name];
if not new_state then
return error(("Invalid state transition: %s cannot %s"):format(self.state, name));
end
local transition_event = {
instance = self;
name = name;
to = new_state;
to_attr = attr;
from = self.state;
from_attr = self.state_attr;
};
local fire_event = self.fsm.events.fire_event;
local ret = notify_transition(fire_event, transition_event);
if ret ~= nil then return nil, ret; end
self.state = new_state;
self.state_attr = attr;
notify_transitioned(fire_event, transition_event);
return true;
end;
end
local function new(desc)
local self = setmetatable({
default_state = desc.default_state;
events = events.new();
}, fsm_mt);
-- states[state_name][transition_name] = new_state_name
local states = { ["*"] = {} };
if desc.default_state then
states[desc.default_state] = {};
end
self.states = states;
local instance_methods = {};
self._instance_mt = { __index = instance_methods };
for _, transition in ipairs(desc.transitions or {}) do
local from_states = transition.from;
if type(from_states) ~= "table" then
from_states = { from_states };
end
for _, from in ipairs(from_states) do
if not states[from] then
states[from] = {};
end
if not states[transition.to] then
states[transition.to] = {};
end
if states[from][transition.name] then
return error(("Duplicate transition in FSM specification: %s from %s"):format(transition.name, from));
end
states[from][transition.name] = transition.to;
end
-- Add public method to trigger this transition
instance_methods[transition.name] = do_transition(transition.name);
end
if desc.state_handlers then
for state_name, handler in pairs(desc.state_handlers) do
self.events.add_handler("enter/"..state_name, handler);
end
end
if desc.transition_handlers then
for transition_name, handler in pairs(desc.transition_handlers) do
self.events.add_handler("transition/"..transition_name, handler);
end
end
if desc.handlers then
self.events.add_handlers(desc.handlers);
end
return self;
end
function fsm_methods:init(state_name, state_attr)
local initial_state = assert(state_name or self.default_state, "no initial state specified");
if not self.states[initial_state] then
return error("Invalid initial state: "..initial_state);
end
local instance = setmetatable({
fsm = self;
state = initial_state;
state_attr = state_attr;
}, self._instance_mt);
if initial_state ~= self.default_state then
local fire_event = self.events.fire_event;
notify_transitioned(fire_event, {
instance = instance;
to = initial_state;
to_attr = state_attr;
from = self.default_state;
});
end
return instance;
end
function fsm_methods:is_instance(o)
local mt = getmetatable(o);
return mt == self._instance_mt;
end
return {
new = new;
is_fsm = is_fsm;
};