Async parallel and promises wont work

Question

I have the following two snippets:

1.this is the unit I would like to run:

health.checkHealth = function (req, res) {
async.parallel({
    cassandra: function (callback) {
        cassandraRepository.ping(callback);
    },
    kafka: function (callback) {
        kafkaHelper.ping(callback);
    },
    vault: function (callback) {
        vaultClient.health()
            .then((isOk)=>{
                 callback(null, isOk)})
            .catch(()=>
                callback(null, false));
    }
}, function (err, result) {
    var response = {};
    if (result.cassandra) {
        response.cassandra = "OK";
    } else {
        response.cassandra = "Failed";
        res.status(500);
    }

    if (result.kafka) {
        response.kafka = "OK";
    } else {
        response.kafka = "Failed";
        res.status(500);
    }

    if (result.vault) {
        response.vault = "OK";
    } else {
        response.vault = "Failed";
        res.status(500);
    }

    res.send(response);
})

}

2.this is the test to check the unit:

     describe('vault is avaliable', function () {
        beforeEach(sinon.test(function () {
            sinon.stub(vaultClient, "health").resolves(true);
        }));

        it('should return 200', sinon.test(function (done) {
            var response = {
                vault: "OK"
            };

            var req = {};
            var res = {};
            var spySend = res.send = sinon.spy();
            var spyStatus = res.status = sinon.spy();

            health.checkHealth(req, res);
            expect(spySend.calledOnce).to.equal(true);
            expect(spySend.calledWith(response));
            expect(spyStatus.calledOnce).to.equal(false);
        }));

    });

My problem is that when I call checkHealth it proceeds to the next line (expect(spySend.calledOnce).to.equal(true);) without waiting for the vaultClient's promise to complete. What do I need to do to make the expects run only after the 'checkHealth' was run.

@Bergi its native promise. there is no way to overcome this using promise? — yuria, Aug 17 '16 at 15:06
Yes. Just drop `async.parallel` and use `Promise.all` instead. You might want to [promisify](http://stackoverflow.com/q/22519784/1048572) `ping` for that. — Bergi, Aug 17 '16 at 15:09

score 2 · Accepted Answer · edited May 23 '17 at 12:08

You do not need to use the async - you can use promises directly in your code with Promise.all as others have suggested.

The code here is using promisifyAll from Bluebird, but you can also convert the APIs to use promises yourself.

//.props is bluebird, you can `.all` with native promises too
Promise.props({
    cassandra: cassandraRepository.pingAsync(); // created by promisifyAll
    kafka: kafkaHelper.pingAsync(),
    vault: vaultClient.health()
}).then(results => {
   // access results.cassandra, results.kafka and results.vaule here
});

Async parallel and promises wont work

1 Answers1