Handle database migrations

This commit is contained in:
Lucas Verney 2018-10-16 23:07:53 +02:00
parent dc9392e6f0
commit 5da06280be
8 changed files with 226 additions and 0 deletions

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@ -77,4 +77,20 @@ If you want to add new data files, especially for public transportation stops
3. Write a preprocessing function in `flatisfy/data_files/__init__.py`. You
can have a look at the existing functions for a model.
## Adding new migrations
If you want to change the database schema, you should create a matching
migration. Here is the way to do it correctly:
1. First, edit the `flatisfy/models` files to create / remove the required
fields. If you create a new database from scratch, these are the files
which will be used.
2. Then, run `alembic revision -m "Some description"` in the root of the git
repo to create a new migration.
3. Finally, edit the newly created migration file under the `migrations/`
folder to add the required code to alter the database (both upgrade and

alembic.ini Normal file
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@ -0,0 +1,74 @@
# A generic, single database configuration.
# path to migration scripts
script_location = migrations
# template used to generate migration files
# file_template = %%(rev)s_%%(slug)s
# timezone to use when rendering the date
# within the migration file as well as the filename.
# 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
# version_locations = %(here)s/bar %(here)s/bat migrations/versions
# the output encoding used when revision files
# are written from script.py.mako
# output_encoding = utf-8
sqlalchemy.url = sqlite:///data/flatisfy.db
# Logging configuration
keys = root,sqlalchemy,alembic
keys = console
keys = generic
level = WARN
handlers = console
qualname =
level = WARN
handlers =
qualname = sqlalchemy.engine
level = INFO
handlers =
qualname = alembic
class = StreamHandler
args = (sys.stderr,)
level = NOTSET
formatter = generic
format = %(levelname)-5.5s [%(name)s] %(message)s
datefmt = %H:%M:%S

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@ -208,3 +208,13 @@ If you want to build the web assets, you can use `npm run build:dev`
(respectively `npm run watch:dev` to build continuously and monitor changes in
source files). You can use `npm run build:prod` (`npm run watch:prod`) to do
the same in production mode (with minification etc).
## Upgrading
To update the app, you can simply `git pull` the latest version. The database
schema might change from time to time. Here is how to update it automatically:
* First, edit the `alembic.ini` file and ensure the `sqlalchemy.url` entry
points to the database URI you are actually using for Flatisfy.
* Then, run `alembic upgrade head` to run the required migrations.

migrations/README Normal file
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@ -0,0 +1 @@
Generic single-database configuration.

migrations/env.py Normal file
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from __future__ import with_statement
from alembic import context
from sqlalchemy import engine_from_config, pool
from logging.config import fileConfig
# 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.
# add your model's MetaData object here
# for 'autogenerate' support
# from myapp import mymodel
# target_metadata = mymodel.Base.metadata
target_metadata = None
# 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")
url=url, target_metadata=target_metadata, literal_binds=True)
with context.begin_transaction():
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 = engine_from_config(
with connectable.connect() as connection:
with context.begin_transaction():
if context.is_offline_mode():

migrations/script.py.mako Normal file
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@ -0,0 +1,24 @@
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"}

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@ -0,0 +1,30 @@
"""Add is_expired
Revision ID: 8155b83242eb
Create Date: 2018-10-16 22:51:25.442678
from alembic import op
import sqlalchemy as sa
# revision identifiers, used by Alembic.
revision = '8155b83242eb'
down_revision = None
branch_labels = None
depends_on = None
def upgrade():
sa.Column('is_expired', sa.Boolean(), default=False)
def downgrade():

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@ -1,3 +1,4 @@
backports.csv; python_version < '3.0'