Added list-templates command and support for custom templates

MANIFEST.in

@@ -2,4 +2,6 @@ include README.md
 include LICENSE 
 include src/flask_migrate/templates/flask/*
 include src/flask_migrate/templates/flask-multidb/*
+include src/flask_migrate/templates/aioflask/*
+include src/flask_migrate/templates/aioflask-multidb/*
 include tests/*

docs/index.rst

@@ -123,8 +123,11 @@ After the extension is initialized, a ``db`` group will be added to the command-
 - ``flask db --help``
     Shows a list of available commands.
 
-- ``flask db init [--multidb]``
-    Initializes migration support for the application. The optional ``--multidb`` enables migrations for multiple databases configured as `Flask-SQLAlchemy binds <http://flask-sqlalchemy.pocoo.org/binds/>`_.
+- ``flask db list-templates``
+    Shows a list of available database repository templates.
+
+- ``flask db init [--multidb] [--template TEMPLATE] [--package]``
+    Initializes migration support for the application. The optional ``--multidb`` enables migrations for multiple databases configured as `Flask-SQLAlchemy binds <http://flask-sqlalchemy.pocoo.org/binds/>`_. The ``--template`` option allows you to explicitly select a database repository template, either from the stock templates provided by this package, or a custom one, given as a path to the template directory. The ``--package`` option tells Alembic to add ``__init__.py`` files in the migrations and versions directories.
 
 - ``flask db revision [--message MESSAGE] [--autogenerate] [--sql] [--head HEAD] [--splice] [--branch-label BRANCH_LABEL] [--version-path VERSION_PATH] [--rev-id REV_ID]``
     Creates an empty revision script. The script needs to be edited manually with the upgrade and downgrade changes. See `Alembic's documentation <http://alembic.zzzcomputing.com/en/latest/index.html>`_ for instructions on how to write migration scripts. An optional migration message can be included.

src/flask_migrate/__init__.py

@@ -30,7 +30,13 @@ def metadata(self):
 
 
 class Config(AlembicConfig):
+    def __init__(self, *args, **kwargs):
+        self.template_directory = kwargs.pop('template_directory', None)
+        super().__init__(*args, **kwargs)
+
     def get_template_directory(self):
+        if self.template_directory:
+            return self.template_directory
         package_dir = os.path.abspath(os.path.dirname(__file__))
         return os.path.join(package_dir, 'templates')
 
@@ -97,19 +103,36 @@ def wrapped(*args, **kwargs):
 
 
 @catch_errors
-def init(directory=None, multidb=False):
+def list_templates():
+    """List available templates."""
+    config = Config()
+    config.print_stdout("Available templates:\n")
+    for tempname in sorted(os.listdir(config.get_template_directory())):
+        with open(
+            os.path.join(config.get_template_directory(), tempname, "README")
+        ) as readme:
+            synopsis = next(readme).strip()
+        config.print_stdout("%s - %s", tempname, synopsis)
+
+
+@catch_errors
+def init(directory=None, multidb=False, template=None, package=False):
     """Creates a new migration repository"""
     if directory is None:
         directory = current_app.extensions['migrate'].directory
-    config = Config()
+    template_directory = None
+    if template is not None and ('/' in template or '\\' in template):
+        template_directory, template = os.path.split(template)
+    config = Config(template_directory=template_directory)
     config.set_main_option('script_location', directory)
     config.config_file_name = os.path.join(directory, 'alembic.ini')
     config = current_app.extensions['migrate'].\
         migrate.call_configure_callbacks(config)
-    if multidb:
-        command.init(config, directory, 'flask-multidb')
-    else:
-        command.init(config, directory, 'flask')
+    if multidb and template is None:
+        template = 'flask-multidb'
+    elif template is None:
+        template = 'flask'
+    command.init(config, directory, template=template, package=package)
 
 
 @catch_errors

src/flask_migrate/cli.py

@@ -1,5 +1,6 @@
 import click
 from flask.cli import with_appcontext
+from flask_migrate import list_templates as _list_templates
 from flask_migrate import init as _init
 from flask_migrate import revision as _revision
 from flask_migrate import migrate as _migrate
@@ -21,15 +22,27 @@ def db():
     pass
 
 
+@db.command()
+@with_appcontext
+def list_templates():
+    """List available templates."""
+    _list_templates()
+
+
 @db.command()
 @click.option('-d', '--directory', default=None,
               help=('Migration script directory (default is "migrations")'))
 @click.option('--multidb', is_flag=True,
               help=('Support multiple databases'))
+@click.option('-t', '--template', default=None,
+              help=('Repository template to use (default is "flask")'))
+@click.option('--package', is_flag=True,
+              help=('Write empty __init__.py files to the environment and '
+                    'version locations'))
 @with_appcontext
-def init(directory, multidb):
+def init(directory, multidb, template, package):
     """Creates a new migration repository."""
-    _init(directory, multidb)
+    _init(directory, multidb, template, package)
 
 
 @db.command()

src/flask_migrate/templates/aioflask-multidb/README

@@ -1 +1 @@
-Multi-database configuration for aioflask and alchemical.
+Multi-database configuration for aioflask.

src/flask_migrate/templates/aioflask/README

@@ -1 +1 @@
-Generic single-database configuration with an async engine.
+Single-database configuration for aioflask.

src/flask_migrate/templates/flask-multidb/README

@@ -1 +1 @@
-Multi-database configuration.
+Multi-database configuration for Flask.

src/flask_migrate/templates/flask/README

@@ -1 +1 @@
-Generic single-database configuration.
+Single-database configuration for Flask.

tests/custom_template/README

@@ -0,0 +1 @@
+Custom template.

tests/custom_template/alembic.ini.mako

@@ -0,0 +1,50 @@
+# Custom template
+
+[alembic]
+# template used to generate migration files
+# file_template = %%(rev)s_%%(slug)s
+
+# set to 'true' to run the environment during
+# the 'revision' command, regardless of autogenerate
+# revision_environment = false
+
+
+# Logging configuration
+[loggers]
+keys = root,sqlalchemy,alembic,flask_migrate
+
+[handlers]
+keys = console
+
+[formatters]
+keys = generic
+
+[logger_root]
+level = WARN
+handlers = console
+qualname =
+
+[logger_sqlalchemy]
+level = WARN
+handlers =
+qualname = sqlalchemy.engine
+
+[logger_alembic]
+level = INFO
+handlers =
+qualname = alembic
+
+[logger_flask_migrate]
+level = INFO
+handlers =
+qualname = flask_migrate
+
+[handler_console]
+class = StreamHandler
+args = (sys.stderr,)
+level = NOTSET
+formatter = generic
+
+[formatter_generic]
+format = %(levelname)-5.5s [%(name)s] %(message)s
+datefmt = %H:%M:%S

tests/custom_template/env.py

@@ -0,0 +1,92 @@
+# Custom template
+from __future__ import with_statement
+
+import logging
+from logging.config import fileConfig
+
+from flask import current_app
+
+from alembic import context
+
+# this is the Alembic Config object, which provides
+# access to the values within the .ini file in use.
+config = context.config
+
+# Interpret the config file for Python logging.
+# This line sets up loggers basically.
+fileConfig(config.config_file_name)
+logger = logging.getLogger('alembic.env')
+
+# add your model's MetaData object here
+# for 'autogenerate' support
+# from myapp import mymodel
+# target_metadata = mymodel.Base.metadata
+config.set_main_option(
+    'sqlalchemy.url',
+    str(current_app.extensions['migrate'].db.get_engine().url).replace(
+        '%', '%%'))
+target_metadata = current_app.extensions['migrate'].db.metadata
+
+# other values from the config, defined by the needs of env.py,
+# can be acquired:
+# my_important_option = config.get_main_option("my_important_option")
+# ... etc.
+
+
+def run_migrations_offline():
+    """Run migrations in 'offline' mode.
+
+    This configures the context with just a URL
+    and not an Engine, though an Engine is acceptable
+    here as well.  By skipping the Engine creation
+    we don't even need a DBAPI to be available.
+
+    Calls to context.execute() here emit the given string to the
+    script output.
+
+    """
+    url = config.get_main_option("sqlalchemy.url")
+    context.configure(
+        url=url, target_metadata=target_metadata, literal_binds=True
+    )
+
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+def run_migrations_online():
+    """Run migrations in 'online' mode.
+
+    In this scenario we need to create an Engine
+    and associate a connection with the context.
+
+    """
+
+    # this callback is used to prevent an auto-migration from being generated
+    # when there are no changes to the schema
+    # reference: http://alembic.zzzcomputing.com/en/latest/cookbook.html
+    def process_revision_directives(context, revision, directives):
+        if getattr(config.cmd_opts, 'autogenerate', False):
+            script = directives[0]
+            if script.upgrade_ops.is_empty():
+                directives[:] = []
+                logger.info('No changes in schema detected.')
+
+    connectable = current_app.extensions['migrate'].db.get_engine()
+
+    with connectable.connect() as connection:
+        context.configure(
+            connection=connection,
+            target_metadata=target_metadata,
+            process_revision_directives=process_revision_directives,
+            **current_app.extensions['migrate'].configure_args
+        )
+
+        with context.begin_transaction():
+            context.run_migrations()
+
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()

tests/custom_template/script.py.mako

@@ -0,0 +1,25 @@
+# Custom template
+"""${message}
+
+Revision ID: ${up_revision}
+Revises: ${down_revision | comma,n}
+Create Date: ${create_date}
+
+"""
+from alembic import op
+import sqlalchemy as sa
+${imports if imports else ""}
+
+# revision identifiers, used by Alembic.
+revision = ${repr(up_revision)}
+down_revision = ${repr(down_revision)}
+branch_labels = ${repr(branch_labels)}
+depends_on = ${repr(depends_on)}
+
+
+def upgrade():
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade():
+    ${downgrades if downgrades else "pass"}

tests/test_custom_template.py

@@ -0,0 +1,75 @@
+import os
+import shutil
+import unittest
+import subprocess
+import shlex
+
+
+def run_cmd(app, cmd):
+    """Run a command and return a tuple with (stdout, stderr, exit_code)"""
+    os.environ['FLASK_APP'] = app
+    process = subprocess.Popen(shlex.split(cmd), stdout=subprocess.PIPE,
+                               stderr=subprocess.PIPE)
+    (stdout, stderr) = process.communicate()
+    print('\n$ ' + cmd)
+    print(stdout.decode('utf-8'))
+    print(stderr.decode('utf-8'))
+    return stdout, stderr, process.wait()
+
+
+class TestMigrate(unittest.TestCase):
+    def setUp(self):
+        os.chdir(os.path.split(os.path.abspath(__file__))[0])
+        try:
+            os.remove('app.db')
+        except OSError:
+            pass
+        try:
+            shutil.rmtree('migrations')
+        except OSError:
+            pass
+        try:
+            shutil.rmtree('temp_folder')
+        except OSError:
+            pass
+
+    def tearDown(self):
+        try:
+            os.remove('app.db')
+        except OSError:
+            pass
+        try:
+            shutil.rmtree('migrations')
+        except OSError:
+            pass
+        try:
+            shutil.rmtree('temp_folder')
+        except OSError:
+            pass
+
+    def test_alembic_version(self):
+        from flask_migrate import alembic_version
+        self.assertEqual(len(alembic_version), 3)
+        for v in alembic_version:
+            self.assertTrue(isinstance(v, int))
+
+    def test_migrate_upgrade(self):
+        (o, e, s) = run_cmd('app.py', 'flask db init -t ./custom_template')
+        self.assertTrue(s == 0)
+        (o, e, s) = run_cmd('app.py', 'flask db migrate')
+        self.assertTrue(s == 0)
+        (o, e, s) = run_cmd('app.py', 'flask db upgrade')
+        self.assertTrue(s == 0)
+
+        from .app import db, User
+        db.session.add(User(name='test'))
+        db.session.commit()
+
+        with open('migrations/README', 'rt') as f:
+            assert f.readline().strip() == 'Custom template.'
+        with open('migrations/alembic.ini', 'rt') as f:
+            assert f.readline().strip() == '# Custom template'
+        with open('migrations/env.py', 'rt') as f:
+            assert f.readline().strip() == '# Custom template'
+        with open('migrations/script.py.mako', 'rt') as f:
+            assert f.readline().strip() == '# Custom template'