fix(computer-use): make Docker ports configurable via environment variables

[gn00295120]

Summary

Replaces hardcoded port numbers with environment variables so the WebUI works correctly with custom Docker port mappings.

Quickstart

• Computer Use Demo

Type of Change

• Bug fix

Problem

When users map Docker ports asymmetrically (e.g. -p 9090:8080), the WebUI breaks because iframe URLs and service bindings use hardcoded port numbers (8080, 8501, 5900, 6080).

Solution

Introduce environment variables for all ports:

Variable	Default	Controls
HTTP_PORT	8080	Landing page HTTP server
STREAMLIT_PORT	8501	Streamlit app
VNC_PORT	5900	x11vnc server
NOVNC_PORT	6080	noVNC websocket proxy
HTTP_HOST_PORT	= HTTP_PORT	Host-side port for browser URLs
STREAMLIT_HOST_PORT	= STREAMLIT_PORT	Host-side Streamlit port
NOVNC_HOST_PORT	= NOVNC_PORT	Host-side noVNC port

The *_HOST_PORT variants are only needed for asymmetric mappings. The landing page index.html is regenerated at startup with correct host-side ports.

Usage

# Symmetric (works as before, no changes needed)
docker run -p 8080:8080 -p 5900:5900 -p 6080:6080 -p 8501:8501 ...

# Asymmetric (now works correctly)
docker run -p 9090:8080 -p 9501:8501 -p 9080:6080 \
  -e HTTP_HOST_PORT=9090 \
  -e STREAMLIT_HOST_PORT=9501 \
  -e NOVNC_HOST_PORT=9080 ...

Files Changed

File	Change
Dockerfile	Add ENV declarations with defaults
image/entrypoint.sh	Read env vars, generate index.html at startup
image/http_server.py	Use HTTP_PORT from env
image/x11vnc_startup.sh	Use VNC_PORT from env
image/novnc_startup.sh	Use VNC_PORT/NOVNC_PORT from env
image/index.html	Add note about runtime regeneration
README.md	Document custom port configuration

Fixes #271

[Copilot]

Pull request overview

This PR fixes the Computer Use Demo WebUI breaking under asymmetric Docker port mappings by making the container’s internal service ports and the browser-facing (host) ports configurable via environment variables, and regenerating the landing page at startup with the correct host-side ports.

Changes:

• Introduces *_PORT and *_HOST_PORT environment variables and uses them across startup scripts.
• Regenerates the landing page index.html at container startup to embed the correct host-side iframe URLs.
• Updates docs to explain custom port mapping configuration.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
computer-use-demo/Dockerfile	Adds default ENV values for the new port configuration variables.
computer-use-demo/image/entrypoint.sh	Exports port env defaults and regenerates static_content/index.html with host-side ports.
computer-use-demo/image/http_server.py	Binds the HTTP server to HTTP_PORT from the environment.
computer-use-demo/image/x11vnc_startup.sh	Uses VNC_PORT env var for x11vnc bind and readiness check.
computer-use-demo/image/novnc_startup.sh	Uses VNC_PORT/NOVNC_PORT env vars for noVNC and readiness check.
computer-use-demo/image/index.html	Adds a note about runtime regeneration (but see review comment re: which file is actually regenerated/served).
computer-use-demo/README.md	Documents how to use the new port environment variables for different mapping scenarios.

Comments suppressed due to low confidence (1)

computer-use-demo/image/novnc_startup.sh:21

• The wait loop doesn’t verify that noVNC actually started: if the timeout elapses, the script will still continue and later print a success message. Consider checking timeout == 0 after the loop and exiting non-zero (optionally printing /tmp/novnc.log) when noVNC fails to bind.

timeout=10
while [ $timeout -gt 0 ]; do
    if netstat -tuln | grep -q ":${NOVNC_PORT} "; then
        break
    fi
    sleep 1
    ((timeout--))

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[gn00295120]

@scutuatua-crypto can you check again ?