lnbits/docs/devs/extensions.md

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layout	parent	title	nav_order
default	For developers	Making extensions	2

Making extensions

Start off by copying the example extension in lnbits/extensions/example into your own:

cp lnbits/extensions/example lnbits/extensions/mysuperplugin -r # Let's not use dashes or anything; it doesn't like those.
cd lnbits/extensions/mysuperplugin
find . -type f -print0 | xargs -0 sed -i 's/example/mysuperplugin/g' # Change all occurrences of 'example' to your plugin name 'mysuperplugin'.

• if you are on macOS and having difficulty with 'sed', consider brew install gnu-sed and use 'gsed', without -0 option after xargs.

Going over the example extension's structure:

• views_api.py: This is where your public API would go. It will be exposed at "$DOMAIN/$PLUGIN/$ROUTE". For example: https://lnbits.com/mysuperplugin/api/v1/tools.
• views.py: The / path will show up as your plugin's home page in lnbits' UI. Other pages you can define yourself. The templates folder should explain itself in relation to this.
• migrations.py: Create database tables for your plugin. They'll be created automatically when you start lnbits.

... This document is a work-in-progress. Send pull requests if you get stuck, so others don't.

Adding new dependencies

If for some reason your extensions needs a new python package to work, you can add a new package using venv, or poerty:

$ poetry add <package>
# or
$ ./venv/bin/pip install <package>

But we need an extra step to make sure LNbits doesn't break in production. Dependencies need to be added to pyproject.toml and requirements.txt, then tested by running on venv and poetry. nix compatability can be tested with nix build .#checks.x86_64-linux.vmTest.

SQLite to PostgreSQL migration

LNbits currently supports SQLite and PostgreSQL databases. There is a migration script tools/conv.py that helps users migrate from SQLite to PostgreSQL. This script also copies all extension databases to the new backend.

Adding mock data to mock_data.zip

mock_data.zip contains a few lines of sample SQLite data and is used in automated GitHub test to see whether your migration in conv.py works. Run your extension and save a few lines of data into a SQLite your_extension.sqlite3 file. Unzip tests/data/mock_data.zip, add your_extension.sqlite3, updated database.sqlite3 and zip it again. Add the updated mock_data.zip to your PR.

running migration locally

you will need a running postgres database

create lnbits user for migration database

sudo su - postgres -c "psql -c 'CREATE ROLE lnbits LOGIN PASSWORD 'lnbits';'"

create migration database

sudo su - postgres -c "psql -c 'CREATE DATABASE migration;'"

run the migration

make test-migration

sudo su - postgres -c "psql -c 'CREATE ROLE lnbits LOGIN PASSWORD 'lnbits';'"

clean migration database afterwards, fails if you try again

sudo su - postgres -c "psql -c 'DROP DATABASE IF EXISTS migration;'"