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firebase emulator ui does not respect "emulator.ui.host" field in firebase.json #6222
Description
[REQUIRED] Environment info
firebase-tools: 12.4.7, 12.4.6, 11.30.0
Platform: macOS (in docker linux/amd64)
[REQUIRED] Test case
FROM node:lts-slim
RUN apt-get update && apt-get install -y autoconf automake bash g++ libtool make openjdk-17-jre-headless python3 && \
java -version
RUN npm install -g firebase-tools@12.4.7 typescript && \
npm cache clean --force && \
firebase setup:emulators:database && \
firebase setup:emulators:firestore && \
firebase setup:emulators:pubsub && \
firebase setup:emulators:storage && \
firebase setup:emulators:ui
VOLUME /root/.cache
WORKDIR /root/app
EXPOSE 4000 4400 5000 5001 8080 8085 9000 9005 9009 9199
CMD ["sh"]{
"emulators": {
"singleProjectMode": false,
"auth": {
"host": "0.0.0.0",
"port": 9098
},
"functions": {
"host": "0.0.0.0",
"port": 5001
},
"firestore": {
"host": "0.0.0.0",
"port": 8080
},
"pubsub": {
"host": "0.0.0.0",
"port": 8085
},
"storage": {
"host": "0.0.0.0",
"port": 9199
},
"eventarc": {
"host": "0.0.0.0",
"port": 9299
},
"ui": {
"host": "0.0.0.0"
},
"hub": {
"host": "0.0.0.0"
},
"logging": {
"host": "0.0.0.0"
}
}
}[REQUIRED] Steps to reproduce
docker build -t fbtest:latest -f Dockerfile
docker run --rm -ti -v $PWD:/root/app /bin/bash
# in container
firebase emulators:start --only auth,firestore --project test[REQUIRED] Expected behavior
Emulator UI should start on 0.0.0.0 based on the settings in firebase.json
[REQUIRED] Actual behavior
Emulator UI starts on 127.0.0.1. Auth and Firestore both respect the Host option.
Activity
dt665m commentedon Aug 7, 2023
After further testing, this is actually working properly. It's just the console output that is not correct
aalej commentedon Aug 7, 2023
Thanks for the detailed report, @dt665m. I was able to reproduce the behavior you mentioned. Just to make sure we’re on the same page, is your expected behavior for the console to output something similar to:
dt665m commentedon Aug 8, 2023
@aalej yes, that indicator for the Emulator UI host in the console (along with the one for Emulator Hub) could clear some confusion. Thanks for taking a look at this!
christhompsongoogle commentedon Aug 8, 2023
Thanks dt665m, I agree this is unintended behavior. We'll get to this when we can, but in the meantime if anyone would like to take a crack at adjusting the output let me know and I can provide some direction.
gauranshahuja commentedon Oct 11, 2026
@christhompsongoogle I'd like to take you up on this one if it's still open.
From reading
printEmulatorOverviewinemulators-start.tsonmain: the table's Host:Port column shows each emulator's listen address throughcommandUtils.getListenOverview, but the "View Emulator UI at" line is built withEmulatorRegistry.url(Emulators.UI), which goes throughgetInfo()andconnectableHostname(). So with"ui": { "host": "0.0.0.0" }the UI listens on 0.0.0.0 while the banner shows 127.0.0.1, which is what @dt665m saw. The "Emulator Hub host:" line usesgetInfo()too, so it has the same mismatch.A link to
http://0.0.0.0:4000can't be opened everywhere (it fails on Windows), so I'd keep the link connectable and show the listen address next to it:and print the Hub's listen address the same way. The per-emulator "View in Emulator UI" links would stay as they are, since they need to be clickable. Does that match what you had in mind, or would you prefer a different output?
christhompsongoogle commentedon Oct 29, 2026
Yes this approach looks great
gauranshahuja commentedon Nov 1, 2026
@christhompsongoogle thanks! The PR is up at #11407, with the startup output from a real run in the description.