Using firebase-functions with Node and exports.foo = functions.database.ref('/object').onWrite(event => {});.
I can deploy to the cloud and test just fine ... and I can easily test http-type functions locally using firebase serve --only functions.
However, I don't see a way to test triggers locally. Is it possible? How?
This in now possible. I finally find this clear medium post which explain how do it : https://medium.com/@moki298/test-your-firebase-cloud-functions-locally-using-cloud-functions-shell-32c821f8a5ce
To run a trigger locally, use the "functions shell" tool :
1 - My code for firestore (the medium post use RealTime Database) :
exports.testTrigger = functions.firestore
.document('messages/{messageId}')
.onCreate((snapshot, context) => {
let message = snapshot.data()
return snapshot.ref.set({
...message,
status : 'sent'
})
})
2 - I run the firebase shell functions in the terminal
firebase functions:shell
3 - I call my "testTrigger" cloud function trigger with data in parameter
testTrigger({text:"hello"})
4- My firestore database has a new "message" updated by my trigger
Very recently, the Firebase team published an update to the Firebase CLI the added the ability to invoke other types of triggers locally. It's documented here. Be sure you've updated your CLI to the latest version to get this new functionality: npm install -g firebase-tools@latest
Doug answered it in the comment. While invoking a trigger is probably useful in some cases (thanks Doug), it isn't the same as a deployed trigger, which can't be done yet.
So I'll stick with deploying remotely and watching the remote log ... good 'ole Marco Polo debugging.
Since May 21st 2020 it's now possible to test triggers locally!
See release blog post https://firebase.googleblog.com/2020/05/local-firebase-emulator-ui.html
Always good to also take a look at the release notes https://firebase.google.com/support/releases#may_21_2020
And note that 8.4 requires Node 10, as discussed in question Update of Firebase CLI to 8.4.0 gives errors about "Unsupported engine" saying '{"node":">=10"}'
