How to connect expo go app through docker devcontainer

Question

problem

cannot connect with my expo app to the expo simulation

setup

• set up a devcontainer with vscode's extension.
• login into my expo account
• successful build
• expo go and laptop in the same network
• has worked before with last linux pc
• node -e 'console.log(os.networkInterfaces())' results:

{
  lo: [
    {
      address: '127.0.0.1',
      netmask: '255.0.0.0',
      internal: true,
      cidr: '127.0.0.1/8', 
      ...
    }
  ],
  eth0: [
    {
      address: '172.17.0.3',
      netmask: '255.255.0.0',
      internal: false,
      cidr: '172.17.0.3/16',
      ...
    }
  ]

I tried

• setting REACT_NATIVE_PACKAGER_HOSTNAME to host's ip
  • without it gives me a link from its eth0
• open mac's firewall to vscode and docker
• turn off mac's firewall
• switch to tunnel connection
  • but this gives an error for another question later
• tried posting and currently waiting responses here while exercising my google-fu

my environment

mac os 12.3 (monterey)
docker 4.7.1
devcontainer from microsoft's nodejs (alpine with node)
expo cli version: v5.3.2

previous environment

ubuntu 21.04
docker ~4.7.1
devcontainer from microsoft's nodejs (alpine with node)
expo cli version: ~5.3.2

to reproduce

1. setup a devcontainer

   • "VARIANT": "14-bullseye"
   • "features": {"git": "latest","aws-cli": "latest","desktop-lite": "latest","python": "latest" }

2. npm i -g expo-cli

3. expo init a new sample project

4. expo start

5. try to connect expo go via the qr

   1. no errors on expo-cli but go-app java.net.ConnectException: Failed to connect to /192.x.x.x:19000

6. if not working like me:

   1. close expo
   2. export REACT_NATIVE_PACKAGER_HOSTNAME=192.168.1.xxx xxx is host's lan ip address
   3. expo start
   4. try connecting with expo go app via qr
      1. no errors on expo-cli but go-app java.net.ConnectException: Failed to connect to /192.x.x.x:19000