launcher.py

import sys
import click
import logging
import asyncio
import asyncpg
import discord
import importlib
import contextlib

from bot import RoboDanny, initial_extensions
from cogs.utils.db import Table

from pathlib import Path

import config
import traceback

try:
    import uvloop
except ImportError:
    pass
else:
    asyncio.set_event_loop_policy(uvloop.EventLoopPolicy())

@contextlib.contextmanager
def setup_logging():
    try:
        # __enter__
        logging.getLogger('discord').setLevel(logging.INFO)
        logging.getLogger('discord.http').setLevel(logging.WARNING)

        log = logging.getLogger()
        log.setLevel(logging.INFO)
        handler = logging.FileHandler(filename='rdanny.log', encoding='utf-8', mode='w')
        dt_fmt = '%Y-%m-%d %H:%M:%S'
        fmt = logging.Formatter('[{asctime}] [{levelname:<7}] {name}: {message}', dt_fmt, style='{')
        handler.setFormatter(fmt)
        log.addHandler(handler)

        yield
    finally:
        # __exit__
        handlers = log.handlers[:]
        for hdlr in handlers:
            hdlr.close()
            log.removeHandler(hdlr)

def run_bot():
    loop = asyncio.get_event_loop()
    log = logging.getLogger()

    try:
        pool = loop.run_until_complete(Table.create_pool(config.postgresql, command_timeout=60))
    except Exception as e:
        click.echo('Could not set up PostgreSQL. Exiting.', file=sys.stderr)
        log.exception('Could not set up PostgreSQL. Exiting.')
        return

    bot = RoboDanny()
    bot.pool = pool
    bot.run()

@click.group(invoke_without_command=True, options_metavar='[options]')
@click.pass_context
def main(ctx):
    """Launches the bot."""
    if ctx.invoked_subcommand is None:
        loop = asyncio.get_event_loop()
        with setup_logging():
            run_bot()

@main.group(short_help='database stuff', options_metavar='[options]')
def db():
    pass

@db.command(short_help='initialises the databases for the bot', options_metavar='[options]')
@click.argument('cogs', nargs=-1, metavar='[cogs]')
@click.option('-q', '--quiet', help='less verbose output', is_flag=True)
def init(cogs, quiet):
    """This manages the migrations and database creation system for you."""

    run = asyncio.get_event_loop().run_until_complete
    try:
        run(Table.create_pool(config.postgresql))
    except Exception:
        click.echo(f'Could not create PostgreSQL connection pool.\n{traceback.format_exc()}', err=True)
        return

    if not cogs:
        cogs = initial_extensions
    else:
        cogs = [f'cogs.{e}' if not e.startswith('cogs.') else e for e in cogs]

    for ext in cogs:
        try:
            importlib.import_module(ext)
        except Exception:
            click.echo(f'Could not load {ext}.\n{traceback.format_exc()}', err=True)
            return

    for table in Table.all_tables():
        try:
            created = run(table.create(verbose=not quiet, run_migrations=False))
        except Exception:
            click.echo(f'Could not create {table.__tablename__}.\n{traceback.format_exc()}', err=True)
        else:
            if created:
                click.echo(f'[{table.__module__}] Created {table.__tablename__}.')
            else:
                click.echo(f'[{table.__module__}] No work needed for {table.__tablename__}.')

@db.command(short_help='migrates the databases')
@click.argument('cog', nargs=1, metavar='[cog]')
@click.option('-q', '--quiet', help='less verbose output', is_flag=True)
@click.pass_context
def migrate(ctx, cog, quiet):
    """Update the migration file with the newest schema."""

    if not cog.startswith('cogs.'):
        cog = f'cogs.{cog}'

    try:
        importlib.import_module(cog)
    except Exception:
        click.echo(f'Could not load {ext}.\n{traceback.format_exc()}', err=True)
        return

    def work(table, *, invoked=False):
        try:
            actually_migrated = table.write_migration()
        except RuntimeError as e:
            click.echo(f'Could not migrate {table.__tablename__}: {e}', err=True)
            if not invoked:
                click.confirm('do you want to create the table?', abort=True)
                ctx.invoke(init, cogs=[cog], quiet=quiet)
                work(table, invoked=True)
            sys.exit(-1)
        else:
            if actually_migrated:
                click.echo(f'Successfully updated migrations for {table.__tablename__}.')
            else:
                click.echo(f'Found no changes for {table.__tablename__}.')

    for table in Table.all_tables():
        work(table)

    click.echo(f'Done migrating {cog}.')

async def apply_migration(cog, quiet, index, *, downgrade=False):
    try:
        pool = await Table.create_pool(config.postgresql)
    except Exception:
        click.echo(f'Could not create PostgreSQL connection pool.\n{traceback.format_exc()}', err=True)
        return

    if not cog.startswith('cogs.'):
        cog = f'cogs.{cog}'

    try:
        importlib.import_module(cog)
    except Exception:
        click.echo(f'Could not load {cog}.\n{traceback.format_exc()}', err=True)
        return

    async with pool.acquire() as con:
        tr = con.transaction()
        await tr.start()
        for table in Table.all_tables():
            try:
                await table.migrate(index=index, downgrade=downgrade, verbose=not quiet, connection=con)
            except RuntimeError as e:
                click.echo(f'Could not migrate {table.__tablename__}: {e}', err=True)
                await tr.rollback()
                break
        else:
            await tr.commit()

@db.command(short_help='upgrades from a migration')
@click.argument('cog', nargs=1, metavar='[cog]')
@click.option('-q', '--quiet', help='less verbose output', is_flag=True)
@click.option('--index', help='the index to use', default=-1)
def upgrade(cog, quiet, index):
    """Runs an upgrade from a migration"""
    run = asyncio.get_event_loop().run_until_complete
    run(apply_migration(cog, quiet, index))

@db.command(short_help='downgrades from a migration')
@click.argument('cog', nargs=1, metavar='[cog]')
@click.option('-q', '--quiet', help='less verbose output', is_flag=True)
@click.option('--index', help='the index to use', default=-1)
def downgrade(cog, quiet, index):
    """Runs an downgrade from a migration"""
    run = asyncio.get_event_loop().run_until_complete
    run(apply_migration(cog, quiet, index, downgrade=True))

async def remove_databases(pool, cog, quiet):
    async with pool.acquire() as con:
        tr = con.transaction()
        await tr.start()
        for table in Table.all_tables():
            try:
                await table.drop(verbose=not quiet, connection=con)
            except RuntimeError as e:
                click.echo(f'Could not drop {table.__tablename__}: {e}', err=True)
                await tr.rollback()
                break
            else:
                click.echo(f'Dropped {table.__tablename__}.')
        else:
            await tr.commit()
            click.echo(f'successfully removed {cog} tables.')

@db.command(short_help="removes a cog's table", options_metavar='[options]')
@click.argument('cog',  metavar='<cog>')
@click.option('-q', '--quiet', help='less verbose output', is_flag=True)
def drop(cog, quiet):
    """This removes a database and all its migrations.

    You must be pretty sure about this before you do it,
    as once you do it there's no coming back.

    Also note that the name must be the database name, not
    the cog name.
    """

    run = asyncio.get_event_loop().run_until_complete
    click.confirm('do you really want to do this?', abort=True)

    try:
        pool = run(Table.create_pool(config.postgresql))
    except Exception:
        click.echo(f'Could not create PostgreSQL connection pool.\n{traceback.format_exc()}', err=True)
        return

    if not cog.startswith('cogs.'):
        cog = f'cogs.{cog}'

    try:
        importlib.import_module(cog)
    except Exception:
        click.echo(f'Could not load {cog}.\n{traceback.format_exc()}', err=True)
        return

    run(remove_databases(pool, cog, quiet))

@main.command(short_help='migrates from JSON files')
@click.argument('cogs', nargs=-1)
@click.pass_context
def convertjson(ctx, cogs):
    """This migrates our older JSON files to PostgreSQL

    Note, this deletes all previous entries in the table
    so you can consider this to be a destructive decision.

    Do not pass in cog names with "cogs." as a prefix.

    This also connects us to Discord itself so we can
    use the cache for our migrations.

    The point of this is just to do some migration of the
    data from v3 -> v4 once and call it a day.
    """

    import data_migrators

    run = asyncio.get_event_loop().run_until_complete

    if not cogs:
        to_run = [(getattr(data_migrators, attr), attr.replace('migrate_', ''))
                  for attr in dir(data_migrators) if attr.startswith('migrate_')]
    else:
        to_run = []
        for cog in cogs:
            try:
                elem = getattr(data_migrators, 'migrate_' + cog)
            except AttributeError:
                click.echo(f'invalid cog name given, {cog}.', err=True)
                return

            to_run.append((elem, cog))

    async def make_pool():
        return await asyncpg.create_pool(config.postgresql)

    try:
        pool = run(make_pool())
    except Exception:
        click.echo(f'Could not create PostgreSQL connection pool.\n{traceback.format_exc()}', err=True)
        return

    client = discord.AutoShardedClient()

    @client.event
    async def on_ready():
        click.echo(f'successfully booted up bot {client.user} (ID: {client.user.id})')
        await client.logout()

    try:
        run(client.login(config.token))
        run(client.connect(reconnect=False))
    except:
        pass

    extensions = ['cogs.' + name for _, name in to_run]
    ctx.invoke(init, cogs=extensions)

    for migrator, _ in to_run:
        try:
            run(migrator(pool, client))
        except Exception:
            click.echo(f'[error] {migrator.__name__} has failed, terminating\n{traceback.format_exc()}', err=True)
            return
        else:
            click.echo(f'[{migrator.__name__}] completed successfully')

if __name__ == '__main__':
    main()