XTMigrations
A fast and easy to use database migration tool for Postgresql, written in Python. This tool helps you keep track of changes in your database.
Let's assume you have an employees table with the fields id and first_name.
You would create a new "migration" as follows:
$ migrate new my first migration
Migration file generated scripts/20221012_234403_996058_my_first_migration.sql
You would edit the file scripts/20221012_234403_996058_my_first_migration.sql as follows:
# Autogenerated: scripts/20221012_234403_996058_my_first_migration.sql
@Up
# Your Up migration goes here (this section describes the database changes you want to apply)
CREATE TABLE employees (id BIGSERIAL, first_name VARCHAR(100));
@Down
# Your Down migration goes here (this section is to "undo" the change in the "Up" section above)
DROP TABLE employees;
To apply your changes you would just run
$ migrate up
$ migrate status # to show your changes
----------------------------------------------- - --------------------
| Name | Status |
----------------------------------------------- - --------------------
| init | Applied |
| 20221012_234403_996058_my_first_migration | Applied. |
----------------------------------------------- - --------------------
On your next software release, you decide that you want to add an email field, you would just do the following
$ migrate new adding email field
Migration file generated scripts/20221012_234936_024571_adding_email_field.sql
You just edit the file scripts/20221012_234936_024571_adding_email_field.sql
# Autogenerated: scripts/20221012_234936_024571_adding_email_field.sql
@Up
# Your Up migration goes here
ALTER TABLE employees ADD COLUMN email VARCHAR(255) DEFAULT NULL;
@Down
# Your Down migration goes here
ALTER TABLE employees DROP COLUMN email;
Before applying the change, you can check the state of your database:
$ migrate status
----------------------------------------------- - --------------------
| Name | Status |
----------------------------------------------- - --------------------
| init | Applied |
| 20221012_234403_996058_my_first_migration | Applied |
| 20221012_234936_024571_adding_email_field | Pending... |
----------------------------------------------- - --------------------
You then apply the new change
$ migrate up
If for some reason, you decide to remove the change, you can undo the migration
$ migrate down
You can also undo multiple migrations. For example, if you want to undo 2 migrations, you would simply run
$ migrate down 2
Installation
Via pip(python 3+ supported)
$ pip install xtmigrations
If you have virtualenv, make sure to run source ~/<virtualenv_folder/bin/activate to be able to have access to the "migrate" command. You can alternatively open a new shell. Make sure that the "migrate" command works by running "migrate version" which should display something like this:
$ migrate version
xtmigrations v1.1.3
To initialize a new migrations directory structure
Go to your project folder (e.g. /Users/myuser/Projects/my_project/) and run
$ migrate init <name>
is your migrations folder. This will create a new / directory structure.
For this example, let's assume we call it "migrations" and it will generate a migrations/ folder. We will run
$ migrate init migrations
Now go inside migrations/ folder
$ cd migrations
Configure config/db.cnf with your database settings
Once it is configured, try to run the following command to make sure that xtmigrations is able to connect to your database.
migrate status
To create a new migration, run the following (no quotes needed)
$ migrate new my first feature
This will create a new migration script (SQL file) under scripts/ folder.
Make sure to edit the new sql file. There is a @Up and a @Down section.
Keep in mind that your SQL inside @Down section should undo the database change defined in the @Up section.
Apply the migration
$ migrate up
To unapply a migration, run the following:
$ migrate down
Environment-specific migrations and seed data.
In some scenarios, we want to prepopulate seed our application with seed data depending on the environment
Use the following command to create an environment-specific migration (Noting that your config/db.cnf is where you define your current environment)
In our example, let's say we want to create a migration for our dev environment and our integration environment. We would run the following
$ migrate new -e dev seed data for development
$ migrate new -e integration seed data for integration testing
Let's assume our current environment is dev (defined in config/db.cnf). To see all migrations for all environment, you can run:
$ migrate status -a
To see all the migrations that will be applied for a particular environment (e.g. integration environment), you can run
$ migrate status -e integration
Note that running migrate up will only run the migration scripts for your current environment
Usage
migrate init <name> | status [-a | -e] | new [-e <env>] <title> | up [<number>] | down [<number>] | help | version
Note: can be 0 which means "all" (migrate down 0 would undo all of the migrations).
License
Copyright © Nejmatek Inc 2022
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
