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 can be configured to only allow authenticated users, or to control which databases, tables, and queries can be accessed by the public or by specific users. 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 clients (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 clients.

The actor dictionary can be any shape - the design of that data structure is left up to the plugins. Actors should always include a unique "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. The root user has all permissions - they can perform any action regardless of other permission rules.

The --root flag is designed for local development and testing. When you start Datasette with --root, the root user automatically receives every permission, including:

• All view permissions (view-instance, view-database, view-table, etc.)

• All write permissions (insert-row, update-row, delete-row, create-table, alter-table, drop-table)

• Debug permissions (permissions-debug, debug-menu)

• Any custom permissions defined by plugins

If you add explicit deny rules in datasette.yaml those can still block the root actor from specific databases or tables.

The --root flag sets an internal root_enabled switch—without it, a signed-in user with {"id": "root"} is treated like any other actor.

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

datasette --root

Datasette will output a single-use-only login URL on startup:

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)

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's permissions system is built around SQL queries. Datasette and its plugins construct SQL queries to resolve the list of resources that an actor can access.

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 actions (view-database, view-table etc) are allowed by Datasette's default configuration: unless you configure additional permission rules unauthenticated users will be allowed to access content.

Other actions, including those introduced by plugins, will default to deny.

Denying all permissions by default

By default, Datasette allows unauthenticated access to view databases, tables, and execute SQL queries.

You may want to run Datasette in a mode where all access is denied by default, and you explicitly grant permissions only to authenticated users, either using the --root mechanism or through configuration file rules or plugins.

Use the --default-deny command-line option to run Datasette in this mode:

datasette --default-deny data.db --root

With --default-deny enabled:

• Anonymous users are denied access to view the instance, databases, tables, and queries

• Authenticated users are also denied access unless they're explicitly granted permissions

• The root user (when using --root) still has access to everything

• You can grant permissions using configuration file rules or plugins

For example, to allow only a specific user to access your instance:

datasette --default-deny data.db --config datasette.yaml

Where datasette.yaml contains:

allow:
  id: alice

This configuration will deny access to everyone except the user with id of alice.

How permissions are resolved

Datasette performs permission checks using the internal await .allowed(*, action, resource, actor=None), method which accepts keyword arguments for action, resource and an optional actor.

resource should be an instance of the appropriate Resource subclass from datasette.resources—for example InstanceResource(), DatabaseResource(database="...)`` or TableResource(database="...", table="..."). This defaults to InstanceResource() if not specified.

When a check runs Datasette gathers allow/deny rules from multiple sources and compiles them into a SQL query. The resulting query describes all of the resources an actor may access for that action, together with the reasons those resources were allowed or denied. The combined sources are:

• allow blocks configured in datasette.yaml.

• Actor restrictions encoded into the actor dictionary or API token.

• The "root" user shortcut when --root (or Datasette.root_enabled) is active, replying True to all permission chucks unless configuration rules deny them at a more specific level.

• Any additional SQL provided by plugins implementing permission_resources_sql(datasette, actor, action).

Datasette evaluates the SQL to determine if the requested resource is included. Explicit deny rules returned by configuration or plugins will block access even if other rules allowed it.

Defining permissions with "allow" blocks

One 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 an action against a specific resource.

Each allow block is compiled into SQL and combined with any plugin-provided rules to produce the cascading allow/deny decisions that power await .allowed(*, action, resource, actor=None).

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

YAML

allow:
  id: root

JSON

{
  "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):

YAML

allow: false

JSON

{
  "allow": false
}

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

YAML

allow: true

JSON

{
  "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):

YAML

allow:
  id:
  - simon
  - cleopaws

JSON

{
  "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):

YAML

allow:
  roles:
  - developer

JSON

{
  "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):

YAML

allow:
  id: "*"

JSON

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

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

YAML

allow:
  unauthenticated: true

JSON

{
  "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":

YAML

allow:
  id:
  - simon
  - cleopaws
  role: ops

JSON

{
  "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 has permission to view a table they will be able to view that table, independent of if they have permission to view the database or instance that the table exists within.

Access to an instance

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

datasette.yaml

title: My private Datasette instance
allow:
  id: root

datasette.json

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

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

datasette.yaml

title: My entirely inaccessible instance
allow: false

datasette.json

{
  "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:

datasette.yaml

databases:
  private:
    allow:
      id: "*"

datasette.json

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

Access to specific tables and views

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

datasette.yaml

databases:
  bakery:
    tables:
      users:
        allow:
          id: '*'

datasette.json

{
  "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:

datasette.yaml

databases:
  dogs:
    queries:
      add_name:
        sql: INSERT INTO names (name) VALUES (:name)
        write: true
        allow:
          id:
          - root

datasette.json

{
  "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:

datasette.yaml

allow_sql: false

datasette.json

{
  "allow_sql": false
}

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

datasette.yaml

allow_sql:
  id: root

datasette.json

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

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

datasette.yaml

databases:
  mydatabase:
    allow_sql:
      id: root

datasette.json

{
  "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:

datasette.yaml

permissions:
  debug-menu:
    id: '*'

datasette.json

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

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

datasette.yaml

databases:
  docs:
    permissions:
      create-table:
        id: editor

datasette.json

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

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

datasette.yaml

databases:
  docs:
    tables:
      reports:
        permissions:
          insert-row:
            id: editor

datasette.json

{
  "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"
        ]
      }
    }
  }
}

Restrictions act as an allowlist layered on top of the actor's existing permissions. They can only remove access the actor would otherwise have—they cannot grant new access. If the underlying actor is denied by allow rules in datasette.yaml or by a plugin, a token that lists that resource in its "_r" section will still be denied.

Checking permissions in plugins

Datasette plugins can check if an actor has permission to perform an action using await .allowed(*, action, resource, actor=None)—for example:

from datasette.resources import TableResource

can_edit = await datasette.allowed(
    action="update-row",
    resource=TableResource(database="fixtures", table="facetable"),
    actor=request.actor,
)

Use await .ensure_permission(action, resource=None, actor=None) when you need to enforce a permission and raise a Forbidden error automatically.

Plugins that define new operations should return Action objects from register_actions(datasette) and can supply additional allow/deny rules by returning PermissionSQL objects from the permission_resources_sql(datasette, actor, action) hook. Those rules are merged with configuration allow blocks and actor restrictions to determine the final result for each check.

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.

Permissions debug tools

The debug tool at /-/permissions is available to any actor with the permissions-debug permission. By default this is just the authenticated root user but you can open it up to all users by starting Datasette like this:

datasette -s permissions.permissions-debug true data.db

The page shows the 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.

Allowed resources view

The /-/allowed endpoint displays resources that the current actor can access for a specified action.

This endpoint provides an interactive HTML form interface. Add .json to the URL path (e.g. /-/allowed.json) to get the raw JSON response instead.

Pass ?action=view-table (or another action) to select the action. Optional parent= and child= query parameters can narrow the results to a specific database/table pair.

This endpoint is publicly accessible to help users understand their own permissions. The potentially sensitive reason field is only shown to users with the permissions-debug permission - it shows the plugins and explanatory reasons that were responsible for each decision.

Permission rules view

The /-/rules endpoint displays all permission rules (both allow and deny) for each candidate resource for the requested action.

This endpoint provides an interactive HTML form interface. Add .json to the URL path (e.g. /-/rules.json?action=view-table) to get the raw JSON response instead.

Pass ?action= as a query parameter to specify which action to check.

This endpoint requires the permissions-debug permission.

Permission check view

The /-/check endpoint evaluates a single action/resource pair and returns information indicating whether the access was allowed along with diagnostic information.

This endpoint provides an interactive HTML form interface. Add .json to the URL path (e.g. /-/check.json?action=view-instance) to get the raw JSON response instead.

Pass ?action= to specify the action to check, and optional ?parent= and ?child= parameters to specify the resource.

The ds_actor cookie

Datasette includes a default authentication plugin which looks for a signed ds_actor cookie containing a JSON actor dictionary. This is how the root actor mechanism works.

Authentication plugins can set signed ds_actor cookies themselves like so:

response = Response.redirect("/")
datasette.set_actor_cookie(response, {"id": "cleopaws"})

The shape of data encoded in the cookie is as follows:

{
  "a": {
    "id": "cleopaws"
  }
}

To implement logout in a plugin, use the delete_actor_cookie() method:

response = Response.redirect("/")
datasette.delete_actor_cookie(response)

Including an expiry time

ds_actor cookies can optionally include a signed expiry timestamp, after which the cookies will no longer be valid. Authentication plugins may chose to use this mechanism to limit the lifetime of the cookie. For example, if a plugin implements single-sign-on against another source it may decide to set short-lived cookies so that if the user is removed from the SSO system their existing Datasette cookies will stop working shortly afterwards.

To include an expiry pass expire_after= to datasette.set_actor_cookie() with a number of seconds. For example, to expire in 24 hours:

response = Response.redirect("/")
datasette.set_actor_cookie(
    response, {"id": "cleopaws"}, expire_after=60 * 60 * 24
)

The resulting cookie will encode data that looks something like this:

{
  "a": {
    "id": "cleopaws"
  },
  "e": "1jjSji"
}

The /-/logout page

The page at /-/logout provides the ability to log out of a ds_actor cookie authentication session.

Built-in actions

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/

view-database

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

resource - datasette.permissions.DatabaseResource(database)

database is the name of the database (string)

view-database-download

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

resource - datasette.resources.DatabaseResource(database)

database is the name of the database (string)

view-table

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

resource - datasette.resources.TableResource(database, table)

database is the name of the database (string)

table is the name of the table (string)

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 - datasette.resources.QueryResource(database, query)

database is the name of the database (string)

query is the name of the canned query (string)

insert-row

Actor is allowed to insert rows into a table.

resource - datasette.resources.TableResource(database, table)

database is the name of the database (string)

table is the name of the table (string)

delete-row

Actor is allowed to delete rows from a table.

resource - datasette.resources.TableResource(database, table)

database is the name of the database (string)

table is the name of the table (string)

update-row

Actor is allowed to update rows in a table.

resource - datasette.resources.TableResource(database, table)

database is the name of the database (string)

table is the name of the table (string)

create-table

Actor is allowed to create a database table.

resource - datasette.resources.DatabaseResource(database)

database is the name of the database (string)

alter-table

Actor is allowed to alter a database table.

resource - datasette.resources.TableResource(database, table)

database is the name of the database (string)

table is the name of the table (string)

drop-table

Actor is allowed to drop a database table.

resource - datasette.resources.TableResource(database, table)

database is the name of the database (string)

table is the name of the table (string)

execute-sql

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

resource - datasette.resources.DatabaseResource(database)

database is the name of the database (string)

See also the default_allow_sql setting.

permissions-debug

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

debug-menu

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