Authentication & Authorization

July 10, 2026 ยท View on GitHub

A mongreldb-server daemon runs in one of three modes:

  1. Open (default) - no auth required.
  2. Bearer token (--auth-token <TOKEN>) - every request must carry an Authorization: Bearer <TOKEN> header.
  3. HTTP Basic (--auth-users) - every request must carry an Authorization: Basic <base64(user:pass)> header.

The Gleam client supports all three through the Options struct passed to mongreldb.connect. This guide shows each mode and how to manage users and roles via SQL when the server is in Basic mode.

Bearer token mode

Start the daemon with a token:

mongreldb-server --auth-token s3cret-token

Connect with token. The token is sent as Authorization: Bearer ... on every request.

let assert Ok(db) =
  mongreldb.connect("http://127.0.0.1:8453", mongreldb.Options(
    token: "s3cret-token",
    username: "",
    password: "",
  ))

case mongreldb.health(db) {
  Ok(True) -> io.println("healthy")
  _ -> io.println("unhealthy")
}

A missing or wrong token surfaces as Error(Auth) (HTTP 401/403).

Basic auth mode

Start the daemon with a users file or inline users:

mongreldb-server --auth-users

Connect with username / password:

let assert Ok(db) =
  mongreldb.connect("http://127.0.0.1:8453", mongreldb.Options(
    token: "",
    username: "admin",
    password: "s3cret",
  ))

The client base64-encodes username:password and sets Authorization: Basic ... on every request.

Token takes precedence

If you supply both, token wins and Basic credentials are ignored. This lets you layer an override without branching:

let assert Ok(db) =
  mongreldb.connect("http://127.0.0.1:8453", mongreldb.Options(
    username: "fallback",
    password: "user",
    token: "overrides-everything",
  ))

User and role management via SQL

When the daemon is in Basic auth mode, users and roles live in the catalog and are managed with SQL. Run these statements through mongreldb.sql.

Create a user

let assert Ok(_) = mongreldb.sql(db, "CREATE USER alice WITH PASSWORD 'hunter2'")

Alter a user

let assert Ok(_) = mongreldb.sql(db, "ALTER USER alice WITH PASSWORD 'new-password'")
let assert Ok(_) = mongreldb.sql(db, "ALTER USER alice ADMIN")

Drop a user

let assert Ok(_) = mongreldb.sql(db, "DROP USER alice")

Roles and grants

let assert Ok(_) = mongreldb.sql(db, "CREATE ROLE analyst")
let assert Ok(_) = mongreldb.sql(db, "GRANT SELECT ON orders TO analyst")
let assert Ok(_) = mongreldb.sql(db, "GRANT analyst TO alice")
let assert Ok(_) = mongreldb.sql(db, "REVOKE SELECT ON orders FROM analyst")
let assert Ok(_) = mongreldb.sql(db, "DROP ROLE analyst")

Common pitfalls

Auth errors look like other errors without a typed match. A 401/403 maps to Error(Auth); a 404 maps to Error(NotFound). Always discriminate with a case rather than string-matching messages.

Forgetting to set auth in production. A client built with default Options sends no credentials. Against an auth-enabled daemon, every call returns Error(Auth). Centralize client construction so the auth option is never accidentally dropped.

Token in version control. Put secrets in the environment, a secret manager, or a file outside the repo. Never commit a real token.

Next steps