datasette-auth-tokens by simonw

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datasette-auth-tokens

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Datasette plugin for authenticating access using API tokens

Installation

Install this plugin in the same environment as Datasette.

datasette install datasette-auth-tokens

Hard-coded tokens

Read about Datasette's authentication and permissions system.

This plugin lets you configure secret API tokens which can be used to make authenticated requests to Datasette.

First, create a random API token. A useful recipe for doing that is the following:

python -c 'import secrets; print(secrets.token_hex(32))'
5f9a486dd807de632200b17508c75002bb66ca6fde1993db1de6cbd446362589

Decide on the actor that this token should represent, for example:

{
    "bot_id": "my-bot"
}

You can then use "allow" blocks to provide that token with permission to access specific actions. To enable access to a configured writable SQL query you could use this in your metadata.json:

{
    "plugins": {
        "datasette-auth-tokens": {
            "tokens": [
                {
                    "token": {
                        "$env": "BOT_TOKEN"
                    },
                    "actor": {
                        "bot_id": "my-bot"
                    }
                }
            ]
        }
    },
    "databases": {
        ":memory:": {
            "queries": {
                "show_version": {
                    "sql": "select sqlite_version()",
                    "allow": {
                        "bot_id": "my-bot"
                    }
                }
            }
        }
    }
}

This uses Datasette's secret configuration values mechanism to allow the secret token to be passed as an environment variable.

Run Datasette like this:

BOT_TOKEN="this-is-the-secret-token" \
    datasette -m metadata.json

You can now run authenticated API queries like this:

curl -H 'Authorization: Bearer this-is-the-secret-token' \
  'http://127.0.0.1:8001/:memory:/show_version.json?_shape=array'
[{"sqlite_version()": "3.31.1"}]

Additionally you can allow passing the token as a query string parameter, although that's disabled by default given the security implications of URLs with secret tokens included. This may be useful to easily allow embedding data between different services.

Simply enable it using the param config value:

{
    "plugins": {
        "datasette-auth-tokens": {
            "tokens": [
                {
                    "token": {
                        "$env": "BOT_TOKEN"
                    },
                    "actor": {
                        "bot_id": "my-bot"
                    },
                }
            ],
            "param": "_auth_token"
        }
    },
    "databases": {
        ":memory:": {
            "queries": {
                "show_version": {
                    "sql": "select sqlite_version()",
                    "allow": {
                        "bot_id": "my-bot"
                    }
                }
            }
        }
    }
}

You can now run authenticated API queries like this:

curl http://127.0.0.1:8001/:memory:/show_version.json?_shape=array&_auth_token=this-is-the-secret-token
[{"sqlite_version()": "3.31.1"}]

Managed tokens mode

datasette-auth-tokens provides a managed tokens mode, where tokens are stored in a SQLite database table and the plugin provides an interface for creating and revoking tokens.

To turn this mode on, add "manage_tokens": true to your plugin configuration in metadata.json:

{
    "plugins": {
        "datasette-auth-tokens": {
            "manage_tokens": true
        }
    }
}

This will add a "Create API token" option to the Datasette menu.

Tokens that are created will be kept in a new _datasette_auth_tokens table.

Users need the auth-tokens-create permission to create tokens. One way to grant that is to add this "permissions" block to your configuration:

{
    "permissions": {
        "auth-tokens-create": {
            "id": "*"
        }
    }
}

Use the "Create API token" option in the Datasette menu or navigate to /-/api/tokens to create tokens and manage tokens.

When you create a new token a signed token string will be presented to you. You need to store this, as it is not stored directly in the database table and can only be retrieved once.

If you have multiple databases attached to Datasette you will need to specify which database should be used for the _datasette_auth_tokens table. You can do this with the manage_tokens_database setting:

{
    "plugins": {
        "datasette-auth-tokens": {
            "manage_tokens": true,
            "manage_tokens_database": "tokens"
        }
    }
}

Now start Datasette like this:

datasette -m metadata.json mydb.db tokens.db --create

The --create option can be used to tell Datasette to create the tokens.db database file if it does not already exist.

Viewing tokens

By default, users can only view tokens that they themselves have created on the /-/api/tokens page.

Grant the auth-tokens-view-all permission to allow a user to view all tokens, even those created by other users.

Revoking tokens

A token can be revoked by the user that created it by clicking the "Revoke this token" button at the bottom of the token page that is linked to from /-/api/tokens.

A user with the auth-tokens-revoke-all permission can revoke any token.

Custom tokens from your database

If you decide not to use managed tokens mode, you can instead configure datasette-auth-tokens to use tokens that are stored in your own custom database tables.

You can do this by configuring a custom SQL query that will execute to test if an incoming token is valid.

Your query needs to take a :token_id parameter and return at least two columns: one called token_secret and one called actor_* - usually actor_id. Further actor_ prefixed columns can be returned to provide more details for the authenticated actor.

Here's a simple example of a configuration query:

select actor_id, actor_name, token_secret from tokens where token_id = :token_id

This can run against a table like this one:

token_id token_secret actor_id actor_name
1 bd3c94f51fcd 78 Cleopaws
2 86681b4d6f66 32 Pancakes

The tokens are formed as the token ID, then a hyphen, then the token secret. For example:

  • 1-bd3c94f51fcd
  • 2-86681b4d6f66

The SQL query will be executed with the portion before the hyphen as the :token_id parameter.

The token_secret value returned by the query will be compared to the portion of the token after the hyphen to check if the token is valid.

Columns with a prefix of actor_ will be used to populate the actor dictionary. In the above example, a token of 2-86681b4d6f66 will become an actor dictionary of {"id": 32, "name": "Pancakes"}.

To configure this, use a "query" block in your plugin configuration like this:

{
    "plugins": {
        "datasette-auth-tokens": {
            "query": {
                "sql": "select actor_id, actor_name, token_secret from tokens where token_id = :token_id",
                "database": "tokens"
            }
        }
    },
    "databases": {
        "tokens": {
            "allow": false
        }
    }
}

The "sql" key here contains the SQL query. The "database" key has the name of the attached database file that the query should be executed against - in this case it would execute against tokens.db.

Securing your custom tokens

If you implement the custom pattern above which reads token_secret from your own tokens table, you need to be aware that anyone with read access to your Datasette instance could read those tokens from your table. This probably isn't what you want!

To avoid this, you should lock down access to that table. The configuration example above shows how to do this using an "allow": false block to deny all access to that tokens database.

Consult Datasette's Permissions documentation for more information about how to lock down this kind of access.