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local set = require "util.set";
insulate("net.resolvers.service", function ()
local adns = {
resolver = function ()
return {
lookup = function (_, cb, qname, qtype, qclass)
if qname == "_xmpp-server._tcp.example.com"
and (qtype or "SRV") == "SRV"
and (qclass or "IN") == "IN" then
cb({
{ -- 60+35+60
srv = { target = "xmpp0-a.example.com", port = 5228, priority = 0, weight = 60 };
};
{
srv = { target = "xmpp0-b.example.com", port = 5216, priority = 0, weight = 35 };
};
{
srv = { target = "xmpp0-c.example.com", port = 5200, priority = 0, weight = 0 };
};
{
srv = { target = "xmpp0-d.example.com", port = 5256, priority = 0, weight = 120 };
};
{
srv = { target = "xmpp1-a.example.com", port = 5273, priority = 1, weight = 30 };
};
{
srv = { target = "xmpp1-b.example.com", port = 5274, priority = 1, weight = 30 };
};
{
srv = { target = "xmpp2.example.com", port = 5275, priority = 2, weight = 0 };
};
});
elseif qname == "_xmpp-server._tcp.single.example.com"
and (qtype or "SRV") == "SRV"
and (qclass or "IN") == "IN" then
cb({
{
srv = { target = "xmpp0-a.example.com", port = 5269, priority = 0, weight = 0 };
};
});
elseif qname == "_xmpp-server._tcp.half.example.com"
and (qtype or "SRV") == "SRV"
and (qclass or "IN") == "IN" then
cb({
{
srv = { target = "xmpp0-a.example.com", port = 5269, priority = 0, weight = 0 };
};
{
srv = { target = "xmpp0-b.example.com", port = 5270, priority = 0, weight = 1 };
};
});
elseif qtype == "A" then
local l = qname:match("%-(%a)%.example.com$") or "1";
local d = ("%d"):format(l:byte())
cb({
{
a = "127.0.0."..d;
};
});
elseif qtype == "AAAA" then
local l = qname:match("%-(%a)%.example.com$") or "1";
local d = ("%04d"):format(l:byte())
cb({
{
aaaa = "fdeb:9619:649e:c7d9::"..d;
};
});
else
cb(nil);
end
end;
};
end;
};
package.loaded["net.adns"] = mock(adns);
local resolver = require "net.resolvers.service";
math.randomseed(os.time());
it("works for 99% of deployments", function ()
-- Most deployments only have a single SRV record, let's make
-- sure that works okay
local expected_targets = set.new({
-- xmpp0-a
"tcp4 127.0.0.97 5269";
"tcp6 fdeb:9619:649e:c7d9::0097 5269";
});
local received_targets = set.new({});
local r = resolver.new("single.example.com", "xmpp-server");
local done = false;
local function handle_target(...)
if ... == nil then
done = true;
-- No more targets
return;
end
received_targets:add(table.concat({ ... }, " ", 1, 3));
end
r:next(handle_target);
while not done do
r:next(handle_target);
end
-- We should have received all expected targets, and no unexpected
-- ones:
assert.truthy(set.xor(received_targets, expected_targets):empty());
end);
it("supports A/AAAA fallback", function ()
-- Many deployments don't have any SRV records, so we should
-- fall back to A/AAAA records instead when that is the case
local expected_targets = set.new({
-- xmpp0-a
"tcp4 127.0.0.97 5269";
"tcp6 fdeb:9619:649e:c7d9::0097 5269";
});
local received_targets = set.new({});
local r = resolver.new("xmpp0-a.example.com", "xmpp-server", "tcp", { default_port = 5269 });
local done = false;
local function handle_target(...)
if ... == nil then
done = true;
-- No more targets
return;
end
received_targets:add(table.concat({ ... }, " ", 1, 3));
end
r:next(handle_target);
while not done do
r:next(handle_target);
end
-- We should have received all expected targets, and no unexpected
-- ones:
assert.truthy(set.xor(received_targets, expected_targets):empty());
end);
it("works", function ()
local expected_targets = set.new({
-- xmpp0-a
"tcp4 127.0.0.97 5228";
"tcp6 fdeb:9619:649e:c7d9::0097 5228";
"tcp4 127.0.0.97 5273";
"tcp6 fdeb:9619:649e:c7d9::0097 5273";
-- xmpp0-b
"tcp4 127.0.0.98 5274";
"tcp6 fdeb:9619:649e:c7d9::0098 5274";
"tcp4 127.0.0.98 5216";
"tcp6 fdeb:9619:649e:c7d9::0098 5216";
-- xmpp0-c
"tcp4 127.0.0.99 5200";
"tcp6 fdeb:9619:649e:c7d9::0099 5200";
-- xmpp0-d
"tcp4 127.0.0.100 5256";
"tcp6 fdeb:9619:649e:c7d9::0100 5256";
-- xmpp2
"tcp4 127.0.0.49 5275";
"tcp6 fdeb:9619:649e:c7d9::0049 5275";
});
local received_targets = set.new({});
local r = resolver.new("example.com", "xmpp-server");
local done = false;
local function handle_target(...)
if ... == nil then
done = true;
-- No more targets
return;
end
received_targets:add(table.concat({ ... }, " ", 1, 3));
end
r:next(handle_target);
while not done do
r:next(handle_target);
end
-- We should have received all expected targets, and no unexpected
-- ones:
assert.truthy(set.xor(received_targets, expected_targets):empty());
end);
it("balances across weights correctly #slow", function ()
-- This mimics many repeated connections to 'example.com' (mock
-- records defined above), and records the port number of the
-- first target. Therefore it (should) only return priority
-- 0 records, and the input data is constructed such that the
-- last two digits of the port number represent the percentage
-- of times that record should (on average) be picked first.
-- To prevent random test failures, we test across a handful
-- of fixed (randomly selected) seeds.
for _, seed in ipairs({ 8401877, 3943829, 7830992 }) do
math.randomseed(seed);
local results = {};
local function run()
local run_results = {};
local r = resolver.new("example.com", "xmpp-server");
local function record_target(...)
if ... == nil then
-- No more targets
return;
end
run_results = { ... };
end
r:next(record_target);
return run_results[3];
end
for _ = 1, 1000 do
local port = run();
results[port] = (results[port] or 0) + 1;
end
local ports = {};
for port in pairs(results) do
table.insert(ports, port);
end
table.sort(ports);
for _, port in ipairs(ports) do
--print("PORT", port, tostring((results[port]/1000) * 100).."% hits (expected "..tostring(port-5200).."%)");
local hit_pct = (results[port]/1000) * 100;
local expected_pct = port - 5200;
--print(hit_pct, expected_pct, math.abs(hit_pct - expected_pct));
assert.is_true(math.abs(hit_pct - expected_pct) < 5);
end
--print("---");
end
end);
end);
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