fix(cli) stop all services when Kong cannot start

- use an xpcall to catch errors and stop all services from there (no
  error checking)
- new test for this behavior

Fix #1530

kong/cmd/start.lua

@@ -12,14 +12,28 @@ local function execute(args)
   }))
 
   local dao = DAOFactory(conf)
-  assert(dao:run_migrations())
-  assert(prefix_handler.prepare_prefix(conf, args.nginx_conf))
-  if conf.dnsmasq then
-    assert(dnsmasq_signals.start(conf))
-  end
-  assert(serf_signals.start(conf, dao))
-  assert(nginx_signals.start(conf))
-  log("Kong started")
+  local err
+  xpcall(function()
+    assert(dao:run_migrations())
+    assert(prefix_handler.prepare_prefix(conf, args.nginx_conf))
+    if conf.dnsmasq then
+      assert(dnsmasq_signals.start(conf))
+    end
+    assert(serf_signals.start(conf, dao))
+    assert(nginx_signals.start(conf))
+    log("Kong started")
+  end, function(e)
+    log.verbose("could not start Kong, stopping services")
+    nginx_signals.stop(conf)
+    serf_signals.stop(conf, dao)
+    if conf.dnsmasq then
+      dnsmasq_signals.stop(conf)
+    end
+    err = e -- cannot throw from this function
+    log.verbose("stopped services")
+  end)
+
+  error(err) -- report to main error handler
 end
 
 local lapp = [[

spec/02-integration/01-cmd/02-start_stop_spec.lua

@@ -203,5 +203,27 @@ describe("kong start/stop", function()
       assert.False(ok)
       assert.matches("nginx is already running in "..helpers.test_conf.prefix, stderr, nil, true)
     end)
+    it("stops other services when could not start", function()
+      local kill = require "kong.cmd.utils.kill"
+      local thread = helpers.tcp_server(helpers.test_conf.proxy_port)
+      finally(function()
+        -- make tcp server receive and close
+        helpers.proxy_client():send {
+          method = "GET",
+          path = "/"
+        }
+        thread:join()
+      end)
+
+      local ok, err = helpers.kong_exec("start --conf "..helpers.test_conf_path, {
+        dnsmasq = true,
+        dns_resolver = ""
+      })
+      assert.False(ok)
+      assert.matches("Address already in use", err, nil, true)
+
+      assert.falsy(kill.is_running(helpers.test_conf.dnsmasq_pid))
+      assert.falsy(kill.is_running(helpers.test_conf.serf_pid))
+    end)
   end)
 end)

spec/helpers.lua

@@ -225,6 +225,7 @@ local function tcp_server(port, ...)
     function(port)
       local socket = require "socket"
       local server = assert(socket.tcp())
+      server:settimeout(10)
       assert(server:setoption('reuseaddr', true))
       assert(server:bind("*", port))
       assert(server:listen())