Create HOWTO_LIBREELEC.md

Documentation about creating a Docker container that will run on very limited systems like LibreELEC.

Author: NamelessCoder

HOWTO_LIBREELEC.md

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+How-to: Install LGWebOSRemote on LibreELEC
+==========================================
+
+This guide explains how to install the LGWebOSRemote CLI utility on limited platforms where
+things like Python, PIP and SSDP may not be available or possible to install, but where
+Docker is an option. The guide applies to LibreELEC specifically (which is exactly such a
+limited platform) but should work just as fine for any other platform that fits the criteria.
+
+Pre-requisites
+--------------------
+
+* Obviously, install the Docker Kodi add-on.
+* Make sure your LibreELEC system has network connectivity.
+* Find out how to use SSH to connect to the LibreELEC system.
+* Connect via SSH, create a directory to hold the Dockerfile, then continue below.
+
+Dockerfile
+---------------
+
+```dockerfile
+FROM python:3.12
+
+ENV VIRTUAL_ENV=/opt/venv
+RUN python3 -m venv $VIRTUAL_ENV
+ENV PATH="$VIRTUAL_ENV/bin:$PATH"
+RUN . /opt/venv/bin/activate && pip install git+https://github.com/klattimer/LGWebOSRemote
+RUN mkdir -m 777 -p /opt/venvs/lgtv/config
+RUN echo '{"mytv" : {"ip": "10.0.0.69", "client-key": "", "mac-address": "34:e6:e6:a5:c8:3c"}}' > /opt/venvs/lgtv/config/config.json
+RUN useradd app
+RUN chown app:app /opt/venvs/lgtv/config
+RUN chown app:app /opt/venvs/lgtv/config/config.json
+
+USER app
+
+RUN . /opt/venv/bin/activate && exec lgtv auth --ssl 10.0.0.69 mytv
+RUN . /opt/venv/bin/activate && exec lgtv setDefault mytv
+
+CMD . /opt/venv/bin/activate && exec lgtv
+```
+
+You'll need to adapt the Dockerfile slightly to fit your system:
+
+* Change the `ip` and `mac-address` settings in the JSON array that is written to `config.json`.
+* Change the IP and TV name in the `auth` command.
+* If you changed the TV name, also change it in the `setDefault` command right below.
+
+Building it
+---------------
+
+```bash
+docker build --network=host -t lgtv/remote .
+```
+
+* The `--network=host` part is vital!
+* While building, your TV will prompt you to authenticate an app. Be ready to accept that dialog.
+* Once built, the Docker image contains configuration to operate one TV.
+
+Running it
+---------------
+
+```bash
+# example with screenOn command
+docker run -t --rm lgtv/remote lgtv --ssl screenOn
+```
+
+* The `--rm` is added to avoid leaving one dead container for every execution.
+* The `-t` is optional but nice for continuous feedback.
+
+The workarounds
+-------------------------
+
+1. LibreELEC won't allow network scan with SSDP to discover the TV, so you can't use `lgtv scan` - you have to use the IP manually.
+2. Docker (or at least the base image used here) won't allow the configuration file to be automatically created - the build routine must create it.
+3. Docker won't persist the configuration file changes so you can't store the client key - the `auth` step is done when building to make sure the built image contains the right configuration.
+4. The base image has no home directory so the configuration file has to be written to `/opt/venvs/lgtv/config/config.json`.