Authentication and permissions#

Datasette doesn't require authentication by default. Any visitor to a Datasette instance can explore the full data and execute read-only SQL queries.

Datasette's plugin system can be used to add many different styles of authentication, such as user accounts, single sign-on or API keys.

Actors#

Through plugins, Datasette can support both authenticated users (with cookies) and authenticated API agents (via authentication tokens). The word "actor" is used to cover both of these cases.

Every request to Datasette has an associated actor value, available in the code as request.actor. This can be None for unauthenticated requests, or a JSON compatible Python dictionary for authenticated users or API agents.

The actor dictionary can be any shape - the design of that data structure is left up to the plugins. A useful convention is to include an "id" string, as demonstrated by the "root" actor below.

Plugins can use the actor_from_request(datasette, request) hook to implement custom logic for authenticating an actor based on the incoming HTTP request.

Using the "root" actor#

Datasette currently leaves almost all forms of authentication to plugins - datasette-auth-github for example.

The one exception is the "root" account, which you can sign into while using Datasette on your local machine. This provides access to a small number of debugging features.

To sign in as root, start Datasette using the --root command-line option, like this:

datasette --root
http://127.0.0.1:8001/-/auth-token?token=786fc524e0199d70dc9a581d851f466244e114ca92f33aa3b42a139e9388daa7
INFO:     Started server process [25801]
INFO:     Waiting for application startup.
INFO:     Application startup complete.
INFO:     Uvicorn running on http://127.0.0.1:8001 (Press CTRL+C to quit)

The URL on the first line includes a one-use token which can be used to sign in as the "root" actor in your browser. Click on that link and then visit http://127.0.0.1:8001/-/actor to confirm that you are authenticated as an actor that looks like this:

{
    "id": "root"
}

Permissions#

Datasette has an extensive permissions system built-in, which can be further extended and customized by plugins.

The key question the permissions system answers is this:

Is this actor allowed to perform this action, optionally against this particular resource?

Actors are described above.

An action is a string describing the action the actor would like to perform. A full list is provided below - examples include view-table and execute-sql.

A resource is the item the actor wishes to interact with - for example a specific database or table. Some actions, such as permissions-debug, are not associated with a particular resource.

Datasette's built-in view permissions (view-database, view-table etc) default to allow - unless you configure additional permission rules unauthenticated users will be allowed to access content.

Permissions with potentially harmful effects should default to deny. Plugin authors should account for this when designing new plugins - for example, the datasette-upload-csvs plugin defaults to deny so that installations don't accidentally allow unauthenticated users to create new tables by uploading a CSV file.

How permissions are resolved#

The datasette.permission_allowed(actor, action, resource=None, default=...) method is called to check if an actor is allowed to perform a specific action.

This method asks every plugin that implements the permission_allowed(datasette, actor, action, resource) hook if the actor is allowed to perform the action.

Each plugin can return True to indicate that the actor is allowed to perform the action, False if they are not allowed and None if the plugin has no opinion on the matter.

False acts as a veto - if any plugin returns False then the permission check is denied. Otherwise, if any plugin returns True then the permission check is allowed.

The resource argument can be used to specify a specific resource that the action is being performed against. Some permissions, such as view-instance, do not involve a resource. Others such as view-database have a resource that is a string naming the database. Permissions that take both a database name and the name of a table, view or canned query within that database use a resource that is a tuple of two strings, (database_name, resource_name).

Plugins that implement the permission_allowed() hook can decide if they are going to consider the provided resource or not.

Defining permissions with "allow" blocks#

The standard way to define permissions in Datasette is to use an "allow" block in the datasette.yaml file. This is a JSON document describing which actors are allowed to perform a permission.

The most basic form of allow block is this (allow demo, deny demo):

allow:
  id: root
{
  "allow": {
    "id": "root"
  }
}

This will match any actors with an "id" property of "root" - for example, an actor that looks like this:

{
    "id": "root",
    "name": "Root User"
}

An allow block can specify "deny all" using false (demo):

allow: false
{
  "allow": false
}

An "allow" of true allows all access (demo):

allow: true
{
  "allow": true
}

Allow keys can provide a list of values. These will match any actor that has any of those values (allow demo, deny demo):

allow:
  id:
  - simon
  - cleopaws
{
  "allow": {
    "id": [
      "simon",
      "cleopaws"
    ]
  }
}

This will match any actor with an "id" of either "simon" or "cleopaws".

Actors can have properties that feature a list of values. These will be matched against the list of values in an allow block. Consider the following actor:

{
    "id": "simon",
    "roles": ["staff", "developer"]
}

This allow block will provide access to any actor that has "developer" as one of their roles (allow demo, deny demo):

allow:
  roles:
  - developer
{
  "allow": {
    "roles": [
      "developer"
    ]
  }
}

Note that "roles" is not a concept that is baked into Datasette - it's a convention that plugins can choose to implement and act on.

If you want to provide access to any actor with a value for a specific key, use "*". For example, to match any logged-in user specify the following (allow demo, deny demo):

allow:
  id: "*"
{
  "allow": {
    "id": "*"
  }
}

You can specify that only unauthenticated actors (from anynomous HTTP requests) should be allowed access using the special "unauthenticated": true key in an allow block (allow demo, deny demo):

allow:
  unauthenticated: true
{
  "allow": {
    "unauthenticated": true
  }
}

Allow keys act as an "or" mechanism. An actor will be able to execute the query if any of their JSON properties match any of the values in the corresponding lists in the allow block. The following block will allow users with either a role of "ops" OR users who have an id of "simon" or "cleopaws":

allow:
  id:
  - simon
  - cleopaws
  role: ops
{
  "allow": {
    "id": [
      "simon",
      "cleopaws"
    ],
    "role": "ops"
  }
}

Demo for cleopaws, demo for ops role, demo for an actor matching neither rule.

The /-/allow-debug tool#

The /-/allow-debug tool lets you try out different "action" blocks against different "actor" JSON objects. You can try that out here: https://latest.datasette.io/-/allow-debug

Access permissions in datasette.yaml#

There are two ways to configure permissions using datasette.yaml (or datasette.json).

For simple visibility permissions you can use "allow" blocks in the root, database, table and query sections.

For other permissions you can use a "permissions" block, described in the next section.

You can limit who is allowed to view different parts of your Datasette instance using "allow" keys in your Configuration.

You can control the following:

  • Access to the entire Datasette instance

  • Access to specific databases

  • Access to specific tables and views

  • Access to specific Canned queries

If a user cannot access a specific database, they will not be able to access tables, views or queries within that database. If a user cannot access the instance they will not be able to access any of the databases, tables, views or queries.

Access to an instance#

Here's how to restrict access to your entire Datasette instance to just the "id": "root" user:

title: My private Datasette instance
allow:
  id: root
{
  "title": "My private Datasette instance",
  "allow": {
    "id": "root"
  }
}

To deny access to all users, you can use "allow": false:

title: My entirely inaccessible instance
allow: false
{
  "title": "My entirely inaccessible instance",
  "allow": false
}

One reason to do this is if you are using a Datasette plugin - such as datasette-permissions-sql - to control permissions instead.

Access to specific databases#

To limit access to a specific private.db database to just authenticated users, use the "allow" block like this:

databases:
  private:
    allow:
      id: "*"
{
  "databases": {
    "private": {
      "allow": {
        "id": "*"
      }
    }
  }
}

Access to specific tables and views#

To limit access to the users table in your bakery.db database:

databases:
  bakery:
    tables:
      users:
        allow:
          id: '*'
{
  "databases": {
    "bakery": {
      "tables": {
        "users": {
          "allow": {
            "id": "*"
          }
        }
      }
    }
  }
}

This works for SQL views as well - you can list their names in the "tables" block above in the same way as regular tables.

Warning

Restricting access to tables and views in this way will NOT prevent users from querying them using arbitrary SQL queries, like this for example.

If you are restricting access to specific tables you should also use the "allow_sql" block to prevent users from bypassing the limit with their own SQL queries - see Controlling the ability to execute arbitrary SQL.

Access to specific canned queries#

Canned queries allow you to configure named SQL queries in your datasette.yaml that can be executed by users. These queries can be set up to both read and write to the database, so controlling who can execute them can be important.

To limit access to the add_name canned query in your dogs.db database to just the root user:

databases:
  dogs:
    queries:
      add_name:
        sql: INSERT INTO names (name) VALUES (:name)
        write: true
        allow:
          id:
          - root
{
  "databases": {
    "dogs": {
      "queries": {
        "add_name": {
          "sql": "INSERT INTO names (name) VALUES (:name)",
          "write": true,
          "allow": {
            "id": [
              "root"
            ]
          }
        }
      }
    }
  }
}

Controlling the ability to execute arbitrary SQL#

Datasette defaults to allowing any site visitor to execute their own custom SQL queries, for example using the form on the database page or by appending a ?_where= parameter to the table page like this.

Access to this ability is controlled by the execute-sql permission.

The easiest way to disable arbitrary SQL queries is using the default_allow_sql setting when you first start Datasette running.

You can alternatively use an "allow_sql" block to control who is allowed to execute arbitrary SQL queries.

To prevent any user from executing arbitrary SQL queries, use this:

allow_sql: false
{
  "allow_sql": false
}

To enable just the root user to execute SQL for all databases in your instance, use the following:

allow_sql:
  id: root
{
  "allow_sql": {
    "id": "root"
  }
}

To limit this ability for just one specific database, use this:

databases:
  mydatabase:
    allow_sql:
      id: root
{
  "databases": {
    "mydatabase": {
      "allow_sql": {
        "id": "root"
      }
    }
  }
}

Other permissions in datasette.yaml#

For all other permissions, you can use one or more "permissions" blocks in your datasette.yaml configuration file.

To grant access to the permissions debug tool to all signed in users, you can grant permissions-debug to any actor with an id matching the wildcard * by adding this a the root of your configuration:

permissions:
  debug-menu:
    id: '*'
{
  "permissions": {
    "debug-menu": {
      "id": "*"
    }
  }
}

To grant create-table to the user with id of editor for the docs database:

databases:
  docs:
    permissions:
      create-table:
        id: editor
{
  "databases": {
    "docs": {
      "permissions": {
        "create-table": {
          "id": "editor"
        }
      }
    }
  }
}

And for insert-row against the reports table in that docs database:

databases:
  docs:
    tables:
      reports:
        permissions:
          insert-row:
            id: editor
{
  "databases": {
    "docs": {
      "tables": {
        "reports": {
          "permissions": {
            "insert-row": {
              "id": "editor"
            }
          }
        }
      }
    }
  }
}

The permissions debug tool can be useful for helping test permissions that you have configured in this way.

API Tokens#

Datasette includes a default mechanism for generating API tokens that can be used to authenticate requests.

Authenticated users can create new API tokens using a form on the /-/create-token page.

Tokens created in this way can be further restricted to only allow access to specific actions, or to limit those actions to specific databases, tables or queries.

Created tokens can then be passed in the Authorization: Bearer $token header of HTTP requests to Datasette.

A token created by a user will include that user's "id" in the token payload, so any permissions granted to that user based on their ID can be made available to the token as well.

When one of these a token accompanies a request, the actor for that request will have the following shape:

{
    "id": "user_id",
    "token": "dstok",
    "token_expires": 1667717426
}

The "id" field duplicates the ID of the actor who first created the token.

The "token" field identifies that this actor was authenticated using a Datasette signed token (dstok).

The "token_expires" field, if present, indicates that the token will expire after that integer timestamp.

The /-/create-token page cannot be accessed by actors that are authenticated with a "token": "some-value" property. This is to prevent API tokens from being used to create more tokens.

Datasette plugins that implement their own form of API token authentication should follow this convention.

You can disable the signed token feature entirely using the allow_signed_tokens setting.

datasette create-token#

You can also create tokens on the command line using the datasette create-token command.

This command takes one required argument - the ID of the actor to be associated with the created token.

You can specify a -e/--expires-after option in seconds. If omitted, the token will never expire.

The command will sign the token using the DATASETTE_SECRET environment variable, if available. You can also pass the secret using the --secret option.

This means you can run the command locally to create tokens for use with a deployed Datasette instance, provided you know that instance's secret.

To create a token for the root actor that will expire in one hour:

datasette create-token root --expires-after 3600

To create a token that never expires using a specific secret:

datasette create-token root --secret my-secret-goes-here

Restricting the actions that a token can perform#

Tokens created using datasette create-token ACTOR_ID will inherit all of the permissions of the actor that they are associated with.

You can pass additional options to create tokens that are restricted to a subset of that actor's permissions.

To restrict the token to just specific permissions against all available databases, use the --all option:

datasette create-token root --all insert-row --all update-row

This option can be passed as many times as you like. In the above example the token will only be allowed to insert and update rows.

You can also restrict permissions such that they can only be used within specific databases:

datasette create-token root --database mydatabase insert-row

The resulting token will only be able to insert rows, and only to tables in the mydatabase database.

Finally, you can restrict permissions to individual resources - tables, SQL views and named queries - within a specific database:

datasette create-token root --resource mydatabase mytable insert-row

These options have short versions: -a for --all, -d for --database and -r for --resource.

You can add --debug to see a JSON representation of the token that has been created. Here's a full example:

datasette create-token root \
    --secret mysecret \
    --all view-instance \
    --all view-table \
    --database docs view-query \
    --resource docs documents insert-row \
    --resource docs documents update-row \
    --debug

This example outputs the following:

dstok_.eJxFizEKgDAMRe_y5w4qYrFXERGxDkVsMI0uxbubdjFL8l_ez1jhwEQCA6Fjjxp90qtkuHawzdjYrh8MFobLxZ_wBH0_gtnAF-hpS5VfmF8D_lnd97lHqUJgLd6sls4H1qwlhA.nH_7RecYHj5qSzvjhMU95iy0Xlc

Decoded:

{
  "a": "root",
  "token": "dstok",
  "t": 1670907246,
  "_r": {
    "a": [
      "vi",
      "vt"
    ],
    "d": {
      "docs": [
        "vq"
      ]
    },
    "r": {
      "docs": {
        "documents": [
          "ir",
          "ur"
        ]
      }
    }
  }
}

Checking permissions in plugins#

Datasette plugins can check if an actor has permission to perform an action using the datasette.permission_allowed(...) method.

Datasette core performs a number of permission checks, documented below. Plugins can implement the permission_allowed(datasette, actor, action, resource) plugin hook to participate in decisions about whether an actor should be able to perform a specified action.

actor_matches_allow()#

Plugins that wish to implement this same "allow" block permissions scheme can take advantage of the datasette.utils.actor_matches_allow(actor, allow) function:

from datasette.utils import actor_matches_allow

actor_matches_allow({"id": "root"}, {"id": "*"})
# returns True

The currently authenticated actor is made available to plugins as request.actor.

The permissions debug tool#

The debug tool at /-/permissions is only available to the authenticated root user (or any actor granted the permissions-debug action).

It shows the thirty most recent permission checks that have been carried out by the Datasette instance.

It also provides an interface for running hypothetical permission checks against a hypothetical actor. This is a useful way of confirming that your configured permissions work in the way you expect.

This is designed to help administrators and plugin authors understand exactly how permission checks are being carried out, in order to effectively configure Datasette's permission system.

Built-in permissions#

This section lists all of the permission checks that are carried out by Datasette core, along with the resource if it was passed.

view-instance#

Top level permission - Actor is allowed to view any pages within this instance, starting at https://latest.datasette.io/

Default allow.

view-database#

Actor is allowed to view a database page, e.g. https://latest.datasette.io/fixtures

resource - string

The name of the database

Default allow.

view-database-download#

Actor is allowed to download a database, e.g. https://latest.datasette.io/fixtures.db

resource - string

The name of the database

Default allow.

view-table#

Actor is allowed to view a table (or view) page, e.g. https://latest.datasette.io/fixtures/complex_foreign_keys

resource - tuple: (string, string)

The name of the database, then the name of the table

Default allow.

view-query#

Actor is allowed to view (and execute) a canned query page, e.g. https://latest.datasette.io/fixtures/pragma_cache_size - this includes executing Writable canned queries.

resource - tuple: (string, string)

The name of the database, then the name of the canned query

Default allow.

insert-row#

Actor is allowed to insert rows into a table.

resource - tuple: (string, string)

The name of the database, then the name of the table

Default deny.

delete-row#

Actor is allowed to delete rows from a table.

resource - tuple: (string, string)

The name of the database, then the name of the table

Default deny.

update-row#

Actor is allowed to update rows in a table.

resource - tuple: (string, string)

The name of the database, then the name of the table

Default deny.

create-table#

Actor is allowed to create a database table.

resource - string

The name of the database

Default deny.

alter-table#

Actor is allowed to alter a database table.

resource - tuple: (string, string)

The name of the database, then the name of the table

Default deny.

drop-table#

Actor is allowed to drop a database table.

resource - tuple: (string, string)

The name of the database, then the name of the table

Default deny.

execute-sql#

Actor is allowed to run arbitrary SQL queries against a specific database, e.g. https://latest.datasette.io/fixtures?sql=select+100

resource - string

The name of the database

Default allow. See also the default_allow_sql setting.

permissions-debug#

Actor is allowed to view the /-/permissions debug page.

Default deny.

debug-menu#

Controls if the various debug pages are displayed in the navigation menu.

Default deny.