{"id": "plugin_hooks:plugin-hook-register-commands", "page": "plugin_hooks", "ref": "plugin-hook-register-commands", "title": "register_commands(cli)", "content": "cli  - the root Datasette  Click command group \n                     \n                         Use this to register additional CLI commands \n                     \n                 \n             \n             Register additional CLI commands that can be run using  datsette yourcommand ... . This provides a mechanism by which plugins can add new CLI commands to Datasette. \n             This example registers a new  datasette verify file1.db file2.db  command that checks if the provided file paths are valid SQLite databases: \n             from datasette import hookimpl\nimport click\nimport sqlite3\n\n\n@hookimpl\ndef register_commands(cli):\n    @cli.command()\n    @click.argument(\n        \"files\", type=click.Path(exists=True), nargs=-1\n    )\n    def verify(files):\n        \"Verify that files can be opened by Datasette\"\n        for file in files:\n            conn = sqlite3.connect(str(file))\n            try:\n                conn.execute(\"select * from sqlite_master\")\n            except sqlite3.DatabaseError:\n                raise click.ClickException(\n                    \"Invalid database: {}\".format(file)\n                ) \n             The new command can then be executed like so: \n             datasette verify fixtures.db \n             Help text (from the docstring for the function plus any defined Click arguments or options) will become available using: \n             datasette verify --help \n             Plugins can register multiple commands by making multiple calls to the  @cli.command()  decorator. Consult the  Click documentation  for full details on how to build a CLI command, including how to define arguments and options. \n             Note that  register_commands()  plugins cannot used with the  --plugins-dir mechanism  - they need to be installed into the same virtual environment as Datasette using  pip install . Provided it has a  setup.py  file (see  Packaging a plugin ) you can run  pip install  directly against the directory in which you are developing your plugin like so: \n             pip install -e path/to/my/datasette-plugin \n             Examples:  datasette-auth-passwords ,  datasette-verify", "breadcrumbs": "[\"Plugin hooks\"]", "references": "[{\"href\": \"https://click.palletsprojects.com/en/latest/commands/#callback-invocation\", \"label\": \"Click command group\"}, {\"href\": \"https://click.palletsprojects.com/\", \"label\": \"Click documentation\"}, {\"href\": \"https://datasette.io/plugins/datasette-auth-passwords\", \"label\": \"datasette-auth-passwords\"}, {\"href\": \"https://datasette.io/plugins/datasette-verify\", \"label\": \"datasette-verify\"}]"}