Blast server (FastAPI rewrite)

A rewrite of the legacy Symfony docker-sf-blast web application. It keeps the blast web parameters and the banks.yml / links.yml configuration files, and submits jobs through either the DRMAA library or the Slurm REST API (JWT auth).

Layout

blast_python/
├── app/
│   ├── main.py          # FastAPI app, routes
│   ├── config.py        # Settings (pydantic-settings)
│   ├── database.py      # SQLAlchemy engine / session
│   ├── models.py        # Job, ResultFile, ResultViewer
│   ├── dbprovider.py    # Databank provider (banks.yml)
│   ├── forms.py         # Web form field choices
│   ├── schemas.py       # BlastRequest model + validation
│   ├── command.py       # blast command builder
│   ├── scheduler.py     # DRMAA + Slurm REST backends
│   ├── mail.py          # result email (smtp or mail binary)
│   ├── templates/       # Jinja2 templates
│   └── static/          # css/js/images
├── bin/                 # blast_links.py, xml2gff3.py
├── config/              # banks.yml, links.yml
├── requirements.txt
└── .env.example

Run

pip install -r requirements.txt
cp .env.example .env
uvicorn app.main:app --reload

The form is served at / and the API docs at /docs.

Tests

pip install -r requirements.txt pytest httpx
pytest

The tests use a fake scheduler (no cluster required) and an in-memory SQLite database. They cover request validation (tests/test_schemas.py), the blast command builder (tests/test_command.py), databank loading (tests/test_dbprovider.py) and the HTTP routes (tests/test_main.py).

Container

docker build -t blast-server .
docker compose up

The image installs the NCBI BLAST tools (needed to run the jobs) alongside the FastAPI server. See docker-compose.yml for the env vars; the Slurm JWT can be mounted as a secret via SLURM_JWT_FILE.

Overriding templates / custom CSS

Mount a directory with your own templates and/or static assets (no image rebuild needed):

• TEMPLATES_OVERRIDE_DIR: a directory searched before the built-in templates. Drop a custom layout.html (or any other template) there.
• STATIC_OVERRIDE_DIR: a directory served at /static/custom/ for custom css/images.
• CUSTOM_CSS: a full URL, an absolute path, or a filename relative to STATIC_OVERRIDE_DIR (e.g. custom.css) that is linked from the layout's <head>.

In docker-compose.yml, uncomment the override volumes and adjust the paths:

    volumes:
      - ./override/templates:/srv/blast/override/templates:ro
      - ./override/static:/srv/blast/override/static:ro
    environment:
      TEMPLATES_OVERRIDE_DIR: /srv/blast/override/templates
      STATIC_OVERRIDE_DIR: /srv/blast/override/static
      CUSTOM_CSS: custom.css

Rotating the Slurm JWT

Point SLURM_JWT_FILE at a file containing the token. The application reads it from disk on every request to the Slurm REST API (rather than caching it in memory), so you can rotate the token simply by replacing the contents of that file — no restart required. Mounting it as a docker secret (/run/secrets/slurm_jwt) works the same way.

At launch, /entrypoint.sh creates a user/group from the UID/GID env vars (names APP_USER/APP_GROUP, default blast) and then drops privileges to run uvicorn as that user. This mirrors docker-sf-blast: jobs are submitted (DRMAA) or authenticated (Slurm) as that user, so they run on the compute nodes under the same uid/gid.

Configuration

See .env.example for all options. Key settings:

• JOBS_METHOD: slurm (default) or drmaa.
• SLURM_REST_URL, SLURM_API_VERSION, SLURM_JWT (or SLURM_JWT_FILE): Slurm REST API endpoint and JWT token sent via X-SLURM-USER-TOKEN.
• DATABASE_URL: SQLAlchemy URL (SQLite/Postgres/MySQL). If empty, the legacy DB_* variables are used.
• BANKS_CONFIG, LINKS_CONFIG: paths to the banks.yml / links.yml files.
• CDD_DELTA_PATH: path to the CDD database (needed for DELTA-BLAST).
• SMTP_*: SMTP settings for result emails (falls back to the mail binary).

Scheduler backends

Scheduler subclasses implement execute, get_status, get_status_as_text, kill and is_finished. SlurmScheduler talks to the Slurm REST API (POST /slurm/<version>/job/submit with a #SBATCH-prefixed script, then polls GET .../job/<id> and deletes to kill). DrmaaScheduler uses the drmaa Python library. get_scheduler() selects the backend from JOBS_METHOD.