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local server = require "net.server";
local log = require "util.logger".init("net.connect");
local new_id = require "util.id".short;
local timer = require "util.timer";
-- TODO #1246 Happy Eyeballs
-- FIXME RFC 6724
-- FIXME Error propagation from resolvers doesn't work
-- FIXME #1428 Reuse DNS resolver object between service and basic resolver
-- FIXME #1429 Close DNS resolver object when done
local pending_connection_methods = {};
local pending_connection_mt = {
__name = "pending_connection";
__index = pending_connection_methods;
__tostring = function (p)
return "<pending connection "..p.id.." to "..tostring(p.target_resolver.hostname)..">";
end;
};
function pending_connection_methods:log(level, message, ...)
log(level, "[pending connection %s] "..message, self.id, ...);
end
-- pending_connections_map[conn] = pending_connection
local pending_connections_map = {};
local pending_connection_listeners = {};
local function attempt_connection(p)
p:log("debug", "Checking for targets...");
p.target_resolver:next(function (conn_type, ip, port, extra, more_targets_available)
if not conn_type then
-- No more targets to try
p:log("debug", "No more connection targets to try", p.target_resolver.last_error);
if next(p.conns) == nil then
p:log("debug", "No more targets, no pending connections. Connection failed.");
if p.listeners.onfail then
p.listeners.onfail(p.data, p.last_error or p.target_resolver.last_error or "unable to resolve service");
end
else
p:log("debug", "One or more connection attempts are still pending. Waiting for now.");
end
return;
end
p:log("debug", "Next target to try is %s:%d", ip, port);
local conn, err = server.addclient(ip, port, pending_connection_listeners, p.options.pattern or "*a",
extra and extra.sslctx or p.options.sslctx, conn_type, extra);
if not conn then
log("debug", "Connection attempt failed immediately: %s", err);
p.last_error = err or "unknown reason";
return attempt_connection(p);
end
p.conns[conn] = true;
pending_connections_map[conn] = p;
if more_targets_available then
timer.add_task(0.250, function ()
if not p.connected then
p:log("debug", "Still not connected, making parallel connection attempt...");
attempt_connection(p);
end
end);
end
end);
end
function pending_connection_listeners.onconnect(conn)
local p = pending_connections_map[conn];
if not p then
log("warn", "Successful connection, but unexpected! Closing.");
conn:close();
return;
end
pending_connections_map[conn] = nil;
if p.connected then
-- We already succeeded in connecting
p.conns[conn] = nil;
conn:close();
return;
end
p.connected = true;
p:log("debug", "Successfully connected");
conn:setlistener(p.listeners, p.data);
return p.listeners.onconnect(conn);
end
function pending_connection_listeners.ondisconnect(conn, reason)
local p = pending_connections_map[conn];
if not p then
log("warn", "Failed connection, but unexpected!");
return;
end
p.conns[conn] = nil;
pending_connections_map[conn] = nil;
p.last_error = reason or "unknown reason";
p:log("debug", "Connection attempt failed: %s", p.last_error);
if p.connected then
p:log("debug", "Connection already established, ignoring failure");
elseif next(p.conns) == nil then
p:log("debug", "No pending connection attempts, and not yet connected");
attempt_connection(p);
else
p:log("debug", "Other attempts are still pending, ignoring failure");
end
end
local function connect(target_resolver, listeners, options, data)
local p = setmetatable({
id = new_id();
target_resolver = target_resolver;
listeners = assert(listeners);
options = options or {};
data = data;
conns = {};
}, pending_connection_mt);
p:log("debug", "Starting connection process");
attempt_connection(p);
end
return {
connect = connect;
};
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