id,page,ref,title,content,breadcrumbs,references
plugin_hooks:plugin-hook-startup,plugin_hooks,plugin-hook-startup,startup(datasette),"This hook fires when the Datasette application server first starts up. 
             Here is an example that validates required plugin configuration. The server will fail to start and show an error if the validation check fails: 
             @hookimpl
def startup(datasette):
    config = datasette.plugin_config(""my-plugin"") or {}
    assert (
        ""required-setting"" in config
    ), ""my-plugin requires setting required-setting"" 
             You can also return an async function, which will be awaited on startup. Use this option if you need to execute any database queries, for example this function which creates the  my_table  database table if it does not yet exist: 
             @hookimpl
def startup(datasette):
    async def inner():
        db = datasette.get_database()
        if ""my_table"" not in await db.table_names():
            await db.execute_write(
                """"""
                create table my_table (mycol text)
            """"""
            )

    return inner 
             Potential use-cases: 
             
                 
                     Run some initialization code for the plugin 
                 
                 
                     Create database tables that a plugin needs on startup 
                 
                 
                     Validate the configuration for a plugin on startup, and raise an error if it is invalid 
                 
             
             
                 If you are writing  unit tests  for a plugin that uses this hook and doesn't exercise Datasette by sending
                    any simulated requests through it you will need to explicitly call  await ds.invoke_startup()  in your tests. An example: 
                 @pytest.mark.asyncio
async def test_my_plugin():
    ds = Datasette()
    await ds.invoke_startup()
    # Rest of test goes here 
             
             Examples:  datasette-saved-queries ,  datasette-init","[""Plugin hooks""]","[{""href"": ""https://datasette.io/plugins/datasette-saved-queries"", ""label"": ""datasette-saved-queries""}, {""href"": ""https://datasette.io/plugins/datasette-init"", ""label"": ""datasette-init""}]"