Moving to alembic for migrations

fastapi-sqlmodel-alembic/README.md

@@ -9,6 +9,13 @@ Bring it up
 docker-compose up -d --build
 ```
 
+*NOTE* changes in your are reflected in the web container since we are mounting
+it as a local volume, and we are serving it using uvicorn from the target mount.
+```
+volumes:
+  - ./project:/usr/src/app
+```
+
 Shut it down
 ```
 docker-compose down -v
@@ -42,6 +49,49 @@ foo=# \dt
  public | song | table | postgres
 ```
 
+### Running Alembic code
+
+See: https://alembic.sqlalchemy.org/en/latest/cookbook.html#using-asyncio-with-alembic
+
+#### Init Alembic
+
+Creates the initial needfuls from alembic. Run it in our container because we don't
+have a local env. We initialize it with the async template also
+```
+docker-compose exec web alembic init -t async migrations
+```
+
+Note we had to modify a lot of the generated code from the above command
+ for this to work with SQLModel and the models it produces. 
+
+#### First Migration
+
+```
+docker-compose exec web alembic revision --autogenerate -m "init"
+```
+
+As second migration example
+
+*IMPORTANT*
+The `--autogenerate` works off of inspecting the running DB schema against your code 
+to see if anything is going to change. Your DB needs to be running to generate these 
+autogenerated changes. Or you could just write your own file by hand. Which could
+happen in more complicated applications.
+
+```
+docker-compose exec web alembic revision --autogenerate -m "add year to Song Model"
+```
+
+#### Applying the Migrations
+
+```
+docker-compose exec web alembic upgrade head
+```
+
+If we wanted to get ambitious we could use an entrypoint script
+that will run alembic migrations for us on container start. You did this in 
+your Wagtail tutorial stuff.
+
 ## Interactions with API
 
 ### Add a song
@@ -55,6 +105,16 @@ Response:
 {"id":1,"artist":"Mogwai","name":"Midnight Fit"}%   
 ```
 
+With the new optional song year
+```
+ curl -d '{"name":"Midnight Fit", "artist":"Mogwai", "year": 2021}' \               
+-H "Content-Type: application/json" -X POST http://localhost:8004/songs
+```
+
+Response:
+```
+{"id":2,"name":"Snakes","artist":"Miyavi","year":2021}
+```
 
 ## Sources Root in Pycharm
 

fastapi-sqlmodel-alembic/project/alembic.ini

@@ -0,0 +1,101 @@
+# A generic, single database configuration.
+
+[alembic]
+# path to migration scripts
+script_location = migrations
+
+# template used to generate migration files
+# file_template = %%(rev)s_%%(slug)s
+
+# sys.path path, will be prepended to sys.path if present.
+# defaults to the current working directory.
+prepend_sys_path = .
+
+# timezone to use when rendering the date within the migration file
+# as well as the filename.
+# If specified, requires the python-dateutil library that can be
+# installed by adding `alembic[tz]` to the pip requirements
+# string value is passed to dateutil.tz.gettz()
+# leave blank for localtime
+# timezone =
+
+# max length of characters to apply to the
+# "slug" field
+# truncate_slug_length = 40
+
+# set to 'true' to run the environment during
+# the 'revision' command, regardless of autogenerate
+# revision_environment = false
+
+# set to 'true' to allow .pyc and .pyo files without
+# a source .py file to be detected as revisions in the
+# versions/ directory
+# sourceless = false
+
+# version location specification; This defaults
+# to migrations/versions.  When using multiple version
+# directories, initial revisions must be specified with --version-path.
+# The path separator used here should be the separator specified by "version_path_separator"
+# version_locations = %(here)s/bar:%(here)s/bat:migrations/versions
+
+# version path separator; As mentioned above, this is the character used to split
+# version_locations. Valid values are:
+#
+# version_path_separator = :
+# version_path_separator = ;
+# version_path_separator = space
+version_path_separator = os  # default: use os.pathsep
+
+# the output encoding used when revision files
+# are written from script.py.mako
+# output_encoding = utf-8
+
+;sqlalchemy.url = driver://user:pass@localhost/dbname
+# YOU COULD JUST DO IT LIKE YOU DO IN FLASK_SQLALCHEMY AND READ THE ENVVAR
+sqlalchemy.url = postgresql+asyncpg://postgres:postgres@db:5432/foo
+
+[post_write_hooks]
+# post_write_hooks defines scripts or Python functions that are run
+# on newly generated revision scripts.  See the documentation for further
+# detail and examples
+
+# format using "black" - use the console_scripts runner, against the "black" entrypoint
+# hooks = black
+# black.type = console_scripts
+# black.entrypoint = black
+# black.options = -l 79 REVISION_SCRIPT_FILENAME
+
+# Logging configuration
+[loggers]
+keys = root,sqlalchemy,alembic
+
+[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
+
+[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

fastapi-sqlmodel-alembic/project/app/main.py

@@ -8,14 +8,15 @@ from app.models import Song, SongCreate
 app = FastAPI()
 
 
-@app.on_event("startup")
+# REMOVED BECAUSE WE NOW USE ALEMBIC TO CREATE AND MANAGE TABLES
-async def on_startup():
+# @app.on_event("startup")
-    """
+# async def on_startup():
-    It's worth noting that from app.models import Song is required.
+#     """
-    Without it, the song table will not be created. Kind of like
+#     It's worth noting that from app.models import Song is required.
-    how I have to do my flask sql alchemy models
+#     Without it, the song table will not be created. Kind of like
-    """
+#     how I have to do my flask sql alchemy models
-    await init_db()
+#     """
+#     await init_db()
 
 
 @app.get("/ping")
@@ -27,12 +28,12 @@ async def pong():
 async def get_songs(session: AsyncSession = Depends(get_session)):
     result = await session.execute(select(Song))
     songs = result.scalars().all()
-    return [Song(name=song.name, artist=song.artist, id=song.id) for song in songs]
+    return [Song(name=song.name, artist=song.artist, id=song.id, year=song.year) for song in songs]
 
 
 @app.post("/songs")
 async def add_song(song: SongCreate, session: AsyncSession = Depends(get_session)):
-    song = Song(name=song.name, artist=song.artist)
+    song = Song(name=song.name, artist=song.artist, year=song.year)
     session.add(song)
     await session.commit()
     await session.refresh(song)  # refreshed becuase of the async nature

fastapi-sqlmodel-alembic/project/app/models.py

@@ -1,3 +1,5 @@
+from typing import Optional
+
 from sqlmodel import SQLModel, Field
 
 
@@ -10,6 +12,7 @@ class SongBase(SQLModel):
     """
     name: str
     artist: str
+    year: Optional[int] = None
 
 
 class Song(SongBase, table=True):

fastapi-sqlmodel-alembic/project/migrations/README

@@ -0,0 +1 @@
+Generic single-database configuration with an async dbapi.

fastapi-sqlmodel-alembic/project/migrations/env.py

@@ -0,0 +1,89 @@
+import asyncio
+from logging.config import fileConfig
+
+from sqlalchemy import engine_from_config
+from sqlalchemy import pool
+from sqlalchemy.ext.asyncio import AsyncEngine
+from sqlmodel import SQLModel                       # NEW
+
+from alembic import context
+
+# I guess we need to import all our models into scope
+from app.models import Song                         # NEW
+
+# 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)
+
+# add your model's MetaData object here
+# for 'autogenerate' support
+# from myapp import mymodel
+# target_metadata = mymodel.Base.metadata
+# target_metadata = None
+target_metadata = SQLModel.metadata             # UPDATED
+
+# 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,
+        dialect_opts={"paramstyle": "named"},
+    )
+
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+def do_run_migrations(connection):
+    context.configure(connection=connection, target_metadata=target_metadata)
+
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+async 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.
+
+    """
+    connectable = AsyncEngine(
+        engine_from_config(
+            config.get_section(config.config_ini_section),
+            prefix="sqlalchemy.",
+            poolclass=pool.NullPool,
+            future=True,
+        )
+    )
+
+    async with connectable.connect() as connection:
+        await connection.run_sync(do_run_migrations)
+
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    asyncio.run(run_migrations_online())

fastapi-sqlmodel-alembic/project/migrations/script.py.mako

@@ -0,0 +1,25 @@
+"""${message}
+
+Revision ID: ${up_revision}
+Revises: ${down_revision | comma,n}
+Create Date: ${create_date}
+
+"""
+from alembic import op
+import sqlalchemy as sa
+import sqlmodel   # NEW
+${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"}

fastapi-sqlmodel-alembic/project/migrations/versions/72cf3e7ce522_init.py

@@ -0,0 +1,40 @@
+"""init
+
+Revision ID: 72cf3e7ce522
+Revises: 
+Create Date: 2022-02-13 18:53:59.037824
+
+"""
+from alembic import op
+import sqlalchemy as sa
+import sqlmodel   # NEW
+
+
+# revision identifiers, used by Alembic.
+revision = '72cf3e7ce522'
+down_revision = None
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.create_table('song',
+    sa.Column('name', sqlmodel.sql.sqltypes.AutoString(), nullable=False),
+    sa.Column('artist', sqlmodel.sql.sqltypes.AutoString(), nullable=False),
+    sa.Column('id', sa.Integer(), nullable=True),
+    sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index(op.f('ix_song_artist'), 'song', ['artist'], unique=False)
+    op.create_index(op.f('ix_song_id'), 'song', ['id'], unique=False)
+    op.create_index(op.f('ix_song_name'), 'song', ['name'], unique=False)
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_index(op.f('ix_song_name'), table_name='song')
+    op.drop_index(op.f('ix_song_id'), table_name='song')
+    op.drop_index(op.f('ix_song_artist'), table_name='song')
+    op.drop_table('song')
+    # ### end Alembic commands ###

fastapi-sqlmodel-alembic/project/migrations/versions/9b802c489174_add_year.py

@@ -0,0 +1,31 @@
+"""add year
+
+Revision ID: 9b802c489174
+Revises: 72cf3e7ce522
+Create Date: 2022-02-13 19:05:06.565340
+
+"""
+from alembic import op
+import sqlalchemy as sa
+import sqlmodel   # NEW
+
+
+# revision identifiers, used by Alembic.
+revision = '9b802c489174'
+down_revision = '72cf3e7ce522'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.add_column('song', sa.Column('year', sa.Integer(), nullable=True))
+    op.create_index(op.f('ix_song_year'), 'song', ['year'], unique=False)
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_index(op.f('ix_song_year'), table_name='song')
+    op.drop_column('song', 'year')
+    # ### end Alembic commands ###

fastapi-sqlmodel-alembic/project/requirements.txt

@@ -1,3 +1,4 @@
+alembic==1.7.1
 asyncpg==0.24.0
 fastapi==0.68.1
 psycopg2-binary==2.9.1