async/await callback function
veeramarni opened this issue · 19 comments
Description
Need support for async/await callback function. It used to work in earlier version 1.5.6 and was failing in later versions.
I have written the test case for it and submitted PR #165 and right now it seems to be failing.
Thanks for quick response. I was using async and await as you see here
@veeramarni you are using a wrong plugin signature. You have to use async or call the next handler.
https://hemerajs.github.io/hemera/1_plugins.html
You mean like this. It still fails.
// Plugin
function plugin(hemera, options, next) {
hemera.add(
{
topic: 'math',
cmd: 'add'
},
async req => {
const result = await Promise.resolve({
result: req.a + req.b
})
return result
}
)
next();
}
hemera.use({
plugin: plugin,
options: {
name: 'myPlugin'
}
})
It works
it.only('Should able to run async await callback function', function(done) {
const nats = require('nats').connect(authUrl)
const hemera = new Hemera(nats)
// Plugin
function plugin(hemera, options, next) {
hemera.add(
{
topic: 'math',
cmd: 'add'
},
async req => {
const result = await Promise.resolve({
result: req.a + req.b
})
return result
}
)
next()
}
hemera.use({
plugin: plugin,
options: {
name: 'myPlugin'
}
})
hemera.ready(async () => {
const resp = await hemera.act({
topic: 'math',
cmd: 'add',
a: 1,
b: 20
})
expect(resp.result).to.be.equals(21)
hemera.close(done)
})
})Do you using the latest hemera version?
@veeramarni could you verify it?
Sorry for the delay, when I was running npm run test to verify this change, I just get following errors. Not sure it was my laptop.
I lost familiarity with mocha as I was using jest for a while. What is the command to run to just run test on that file?
Requirements:
- nats server installed globally
- Nodejs. >=4.5
- Nodejs >= 8 for async / await tests
npm run test is correct. Could it be that you have running a nats server beside the tests? Hemera is tested on windows and Linux from nodejs 4-8 via CI.
I ran into a similar problem running tests on my system. The issue is that when a test fails, the hemera-testsuite module does not kill the nats server even though the call is listed in after(). I manually fix this each time the tests fail by running the following on my mac:
kill $(lsof -n -i4TCP:6242 | grep LISTEN | awk '{print $2}')
I believe so, yes
Can you verify it? When yes we should check the bootstrap script.
After is not being called when hemera tests fail. As an experiment, I converted hemera.ready to an async function which means the tests can be structured like:
it('Should call after when failing inside hemera act response', async () => {
const nats = require('nats').connect(authUrl)
const hemera = new Hemera(nats)
try {
await hemera.ready()
hemera.add(
{
topic: 'math',
cmd: 'multiply'
},
(req, cb) => {
cb(null, req.a * req.b)
}
)
const resp = await hemera.act(
{
topic: 'math',
cmd: 'multiply',
a: 0,
b: 0
}
)
expect(resp).to.be.equals(-1)
} finally {
hemera.close()
}
})With this change, the after is called and the server is killed
The issue is that the expect causes an exception in an async callback. You could also try/catch the 'expect' failure and call done(err) to get around the problem
The after callback isn't called without the try / catch block? It's correct that expect throws and your solution looks reasonable but you don't have to catch the assertion.
I think that if the expect is inside a callback that there's no way for mocha to detect the exception. So you have to handle calling 'done' yourself or async/await the entire chain.
This seems to describe what we're running into here.
https://stackoverflow.com/a/26793989/1458832
yes, that's correct because mocha cant catch error which is thrown asynchronously but in your example above there is no callback.
The async test is executed asynchronously.
Closing due to inactivity.