Unable to connect to firebase emulator suite with exec

Question

Started firebase project emulators (which uses cloud functions and firestore) with below command

firebase emulators:start

It runs successfully and gives me a path to connect to the functions and shows a local host url for firestore too.

Then, to execute my jest tests, ran the below command

firebase emulators:exec --only firestore jest

As per the documentation, to connect to local firstore, we need to use exec. But its throwing below error.

i  emulators: Starting emulators: firestore
⚠  emulators: emulator hub unable to start on port 4400, starting on 4401
✔  hub: emulator hub started at http://localhost:4401
i  Shutting down emulators.
i  Stoppping emulator hub
⚠  Port 8080 is not open on localhost, could not start firestore emulator.
i  To select a different host/port for the emulator, update your "firebase.json":
    {
      // ...
      "emulators": {
        "firestore": {
          "host": "HOST",
          "port": "PORT"
        }
      }
    }
i  Shutting down emulators.
Error: Could not start firestore emulator, port taken.

This error is thrown everytime when I run exec command. Can someone point out what could be wrong?

Edit: Logs from firebase emulators:start

firebase emulators:start
i  emulators: Starting emulators: functions, firestore, hosting, pubsub
✔  hub: emulator hub started at http://localhost:4400
⚠  Your requested "node" version "8" doesn't match your global version "10"
✔  functions: functions emulator started at http://localhost:5001
i  firestore: Serving ALL traffic (including WebChannel) on http://localhost:8080
⚠  firestore: Support for WebChannel on a separate port (8081) is DEPRECATED and will go away soon. Please use port above instead.
i  firestore: firestore emulator logging to firestore-debug.log
✔  firestore: firestore emulator started at http://localhost:8080
i  firestore: For testing set FIRESTORE_EMULATOR_HOST=localhost:8080
i  hosting[website]: Serving hosting files from: public
✔  hosting[website]: Local server: http://localhost:5000
i  hosting[admin]: Serving hosting files from: public
✔  hosting[admin]: Local server: http://localhost:5005
i  hosting[b2b]: Serving hosting files from: public
✔  hosting[b2b]: Local server: http://localhost:5006
i  hosting[b2c]: Serving hosting files from: public
✔  hosting[b2c]: Local server: http://localhost:5007
i  hosting[sdk]: Serving hosting files from: public
✔  hosting[sdk]: Local server: http://localhost:5008
✔  hosting: hosting emulator started at http://localhost:5000
i  pubsub: pubsub emulator logging to pubsub-debug.log
✔  pubsub: pubsub emulator started at http://localhost:8085

Update

With a fresh start also the mentioned error is shown. But killing the port made it work.

Added below in scipts part of package.json

"kill": "npx kill-port 5000 5001 8080 8085 4000 9229"

and run

npm run kill

Here all above listed ports aren't reqired. Just 8080 might work in your case but I have other ports too being used by the emulator.

Answer 1

lsof command is not availalble on windows powershell.

A better cross-platform solution is: npx kill-port 8080

Answer 2

Type this in your terminal, where 8080 is your port number:

lsof -ti tcp:8080 | xargs kill

Reason: Failed quitting the previous firebase emulator.