log4js-node/test/tap/cluster-test.js

const { test } = require("tap");
const cluster = require("cluster");
const log4js = require("../../lib/log4js");
const recorder = require("../../lib/appenders/recording");

log4js.configure({
  appenders: {
    vcr: { type: "recording" }
  },
  categories: { default: { appenders: ["vcr"], level: "debug" } }
});

if (cluster.isMaster) {
  cluster.fork();

  const masterLogger = log4js.getLogger("master");
  const masterPid = process.pid;
  masterLogger.info("this is master");

  let workerLevel;
  cluster.on("message", (worker, message) => {
    if (worker.type || worker.topic) {
      message = worker;
    }
    if (message.type && message.type === "::testing") {
      workerLevel = message.level;
    }
  });

  cluster.on("exit", worker => {
    const workerPid = worker.process.pid;
    const logEvents = recorder.replay();

    test("cluster master", batch => {
      batch.test("events should be logged", t => {
        t.equal(logEvents.length, 3);

        t.equal(logEvents[0].categoryName, "master");
        t.equal(logEvents[0].pid, masterPid);

        t.equal(logEvents[1].categoryName, "worker");
        t.equal(logEvents[1].pid, workerPid);
        // serialising errors with stacks intact
        t.type(logEvents[1].data[1], "Error");
        t.contains(logEvents[1].data[1].stack, "Error: oh dear");
        // serialising circular references in objects
        t.type(logEvents[1].data[2], "object");
        t.type(logEvents[1].data[2].me, "object");
        // serialising errors with custom properties
        t.type(logEvents[1].data[3], "Error");
        t.contains(logEvents[1].data[3].stack, "Error: wtf");
        t.equal(logEvents[1].data[3].alert, "chartreuse");
        // serialising things that are not errors, but look a bit like them
        t.type(logEvents[1].data[4], "object");
        t.equal(logEvents[1].data[4].stack, "this is not a stack trace");

        t.equal(logEvents[2].categoryName, "log4js");
        t.equal(logEvents[2].level.toString(), "ERROR");
        t.equal(logEvents[2].data[0], "Unable to parse log:");

        t.end();
      });

      batch.end();
    });

    test("cluster worker", batch => {
      batch.test("logger should get correct config", t => {
        t.equal(workerLevel, "DEBUG");
        t.end();
      });
      batch.end();
    });
  });
} else {
  const workerLogger = log4js.getLogger("worker");
  // test for serialising circular references
  const circle = {};
  circle.me = circle;
  // test for serialising errors with their own properties
  const someError = new Error("wtf");
  someError.alert = "chartreuse";
  // test for serialising things that look like errors but aren't.
  const notAnError = { stack: "this is not a stack trace" };
  workerLogger.info(
    "this is worker",
    new Error("oh dear"),
    circle,
    someError,
    notAnError
  );
  // can't run the test in the worker, things get weird
  process.send({
    type: "::testing",
    level: workerLogger.level.toString()
  });
  // test sending a badly-formed log message
  process.send({ topic: "log4js:message", data: { cheese: "gouda" } });
  cluster.worker.disconnect();
}