spam accounts management for forgejo

Usage

• remove model.json if you want to start with no pre-existing model of what is spam or not. Or keep it to use the current classifier. The file gets updated when using the tool: the classifier learns from spam/legit decisions and should get progressively better at identifying spam.
• run: cargo run
• classify users as spam/not spam. By default the classification is stored locally in db.json, no concrete action is taken. (see the ACTUALLY_BAN_USERS environment variable below.)

Configuration

Forgery reads the following environment variables:

• FORGE_URL (mandatory): url of the forgejo instance (e.g. https://git.deuxfleurs.fr)
• FORGE_API_TOKEN (mandatory): Forgejo API token granting admin access. You can generate an API token using the Forgejo web interface in Settings -> Applications -> Generate New Token.
• ACTUALLY_BAN_USERS (default: false): define it to true to actually lock user accounts, send notification emails and eventually delete user accounts. Otherwise, no actual action is taken: spammers are only listed in the database. The variable should be set in production, but probably not for testing.
• STORAGE_BACKEND (default: local): either local or s3. Chose local to store the application state to local files, or s3 to store them in S3-compatible storage (see below for corresponding configuration variables).
• BIND_ADDR (default: 127.0.0.1:8080): address on which the webserver listens

Environment variables read when ACTUALLY_BAN_USERS=true:

• SMTP_ADDRESS: address of the SMTP relay used to send email notifications
• SMTP_USERNAME: SMTP username
• SMTP_PASSWORD: SMTP password
• ADMIN_CONTACT_EMAIL: email that can be used to contact admins of your instance (included in the notification email sent when locking accounts)
• ORG_NAME: organization name (used in the notification email sent when locking accounts)

Environment variables read when STORAGE_BACKEND=local:

• STORAGE_LOCAL_DIR (default: .): path to a local directory where to store the application data (as two files db.json and model.json).

Environment variables read when STORAGE_BACKEND=s3:

• STORAGE_S3_BUCKET: name of the bucket where to store the application data (as two entries db.json and model.json).
• AWS_DEFAULT_REGION: S3 endpoint region
• AWS_ENDPOINT_URL: S3 endpoint URL
• AWS_ACCESS_KEY_ID: S3 key id
• AWS_SECRET_ACCESS_KEY: S3 key secret

Todos

• discuss the current design choices for when locking the account/sending a notification email fails. (Current behavior is to periodically retry, avoid deleting if the account could not be locked, but delete the account after the grace period even if the email could not be sent…)
• auth: add support for connecting to the forge using oauth?
• improve error handling? currently the app will panic if writing to the storage backend fails. Can we do better?