import argparse

import sys

from contextlib import ExitStack

from sqlalchemy.engine import create_engine

from sqlalchemy.schema import MetaData

if sys.version_info < (3, 8):

from importlib_metadata import entry_points, version

else:

from importlib.metadata import entry_points, version

def main() -> None:

generators = {ep.name: ep for ep in entry_points()['sqlacodegen.generators']}

parser = argparse.ArgumentParser(

description='Generates SQLAlchemy model code from an existing database.')

parser.add_argument('url', nargs='?', help='SQLAlchemy url to the database')

parser.add_argument('--option', nargs='*', help="options passed to the generator class")

parser.add_argument('--version', action='store_true', help="print the version number and exit")

parser.add_argument('--schemas', help='load tables from the given schemas (comma separated)')

parser.add_argument('--generator', choices=generators, default='declarative',

help="generator class to use")

parser.add_argument('--tables', help='tables to process (comma-separated, default: all)')

parser.add_argument('--noviews', action='store_true', help="ignore views")

parser.add_argument('--outfile', help='file to write output to (default: stdout)')

args = parser.parse_args()

if args.version:

print(version('sqlacodegen'))

return

if not args.url:

print('You must supply a url\n', file=sys.stderr)

parser.print_help()

return

# Use reflection to fill in the metadata

engine = create_engine(args.url)

metadata = MetaData()

tables = args.tables.split(',') if args.tables else None

schemas = args.schemas.split(',') if args.schemas else [None]

for schema in schemas:

metadata.reflect(engine, schema, not args.noviews, tables)

# Instantiate the generator

generator_class = generators[args.generator].load()

generator = generator_class(metadata, engine, set(args.option or ()))

# Open the target file (if given)

with ExitStack() as stack:

if args.outfile:

outfile = open(args.outfile, 'w', encoding='utf-8')

stack.enter_context(outfile)

else:

outfile = sys.stdout

# Write the generated model code to the specified file or standard output

outfile.write(generator.generate())