44 lines
1.6 KiB
Markdown
44 lines
1.6 KiB
Markdown
# capsulflask
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Python Flask web application for capsul.org
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## how to run locally
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Ensure you have the pre-requisites for the psycopg2 Postgres database adapter package
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```
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sudo apt-get install python3-dev libpq-dev
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pg_config --version
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```
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Create python virtual environment and install packages
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```
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python3 -m venv .venv
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source .venv/bin/activate
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pip install -r requirements.txt
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```
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Run an instance of Postgres (I used docker for this, you can use whatever you want, point is its listening on localhost:5432)
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```
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docker run --rm -it -e POSTGRES_PASSWORD=dev -p 5432:5432 postgres
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```
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Run the app
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```
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FLASK_APP=capsulflask flask run
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```
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## postgres database schema management
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capsulflask has a concept of a schema version. When the application starts, it will query the database for a table named
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`schemaversion` that has one row and one column (`version`). If the `version` it finds is not equal to the `desiredSchemaVersion` variable set in `db.py`, it will run migration scripts from the `schema_migrations` folder one by one until the `schemaversion` table shows the correct version.
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For example, the script named `02_up_xyz.sql` should contain code that migrates the database from schema version 1 to schema version 2. Likewise, the script `02_down_xyz.sql` should contain code that migrates from schema version 2 back to schema version 1.
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**IMPORTANT: if you need to make changes to the schema, make a NEW schema version. DO NOT EDIT the existing schema versions.**
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In general, for safety, schema version upgrades should not delete data. Schema version downgrades will simply throw an error and exit for now. |