log4js-node/test/tap/tcp-appender-test.js

const { test } = require("tap");
const net = require("net");
const log4js = require("../../lib/log4js");
const LoggingEvent = require("../../lib/LoggingEvent");

const messages = [];
const server = net.createServer(socket => {
  socket.setEncoding("utf8");
  socket.on("data", data => {
    data
      .split("__LOG4JS__")
      .filter(s => s.length)
      .forEach(s => {
        messages.push(LoggingEvent.deserialise(s));
      });
  });
});

server.unref();

server.listen(() => {
  const { port } = server.address();
  log4js.configure({
    appenders: {
      tcp: { type: "tcp", port }
    },
    categories: {
      default: { appenders: ["tcp"], level: "debug" }
    }
  });

  const logger = log4js.getLogger();
  logger.info("This should be sent via TCP.");
  logger.info("This should also be sent via TCP and not break things.");
  log4js.shutdown(() => {
    server.close(() => {
      test("TCP Appender", batch => {
        batch.test("should send log messages as JSON over TCP", t => {
          t.equal(messages.length, 2);
          t.match(messages[0], {
            data: ["This should be sent via TCP."],
            categoryName: "default",
            context: {},
            level: { levelStr: "INFO" }
          });
          t.match(messages[1], {
            data: ["This should also be sent via TCP and not break things."],
            categoryName: "default",
            context: {},
            level: { levelStr: "INFO" }
          });
          t.end();
        });
        batch.end();
      });
    });
  });
});