Python Client API
Before going through this guide, make sure you follow the Oso Cloud Quickstart to get your Oso Cloud API Key properly set in your environment.
First, install the oso-cloud package on PyPI:
pip install oso-cloud
Instantiating an Oso Cloud client
The Oso Cloud client provides an Oso class that takes your Oso Cloud URL and API key:
from oso_cloud import Osooso = Oso(url="https://cloud.osohq.com", api_key=YOUR_API_KEY)# Later:oso.tell({"name": "has_role", "args": [user, role, resource]})# Wherever authorization needs to be performed:if oso.authorize(user, action, resource): # Action is allowed
You should instantiate one client and share it across your application. Under the hood, it reuses connections to avoid paying the cost of negotiating a new connection on every request.
Specifying an Oso Fallback host
If you have deployed Oso Fallback nodes to your infrastructure, you may specify the host when instantiating the Oso Cloud client.
# Assumes Oso Fallback is hosted at http://localhost:8080oso = Oso(url="https://cloud.osohq.com", api_key=YOUR_API_KEY, fallback_url="http://localhost:8080")
Passing application entities into the client
Under the hood, Oso Cloud represents an entity in your application as a combination of a type and an ID,
which together uniquely identify the entity.
The Python client represents these entities as dictionaries with both type and id properties.
For example:
alice = {"type": "User", "id": "alice"}anvils_repository = {"type": "Repostory", "id": "anvils"}
You will pass dictionaries like these into nearly every function call you make to the Python client.
Management API
Add fact: oso.tell(fact)
Adds a fact named name with the provided arguments. Example:
oso.tell({ "name": "has_role", "args": [{"type": "User", "id": "bob"}, "owner", {"type": "Organization", "id": "acme"}]})
For Oso Cloud developer accounts, bulk_tell, bulk_delete, and bulk calls
are limited to 20 facts. If you attempt to send more than 20 facts, these
functions will throw an error.
Add many facts: oso.bulk_tell([*facts])
Adds many facts at once. Example:
oso.bulk_tell([ { "name": "has_role", "args": [{"type": "User", "id": "bob"}, "owner", {"type": "Organization", "id": "acme"}] }, { "name": "has_role", "args": [{"type": "User", "id": "bob"}, "maintainer", {"type": "Repository", "id": "anvils"}] },])
Delete fact: oso.delete(fact)
Deletes a fact. Does not throw an error if the fact is not found. Example:
oso.delete({ "name": "has_role", "args": [{"type": "User", "id": "bob"}, "maintainer", {"type": "Repository", "id": "anvils"}]})
Delete many facts: oso.bulk_delete([*facts])
Deletes many facts at once. Does not throw an error when some of the facts are not found. Example:
oso.bulk_delete([ { "name": "has_role", "args": [{"type": "User", "id": "bob"}, "owner", {"type": "Organization", "id": "acme"}] }, { "name": "has_role", "args": [{"type": "User", "id": "bob"}, "maintainer", {"type": "Repository", "id": "anvils"}] },])
Transactionally delete and add facts: oso.bulk(delete=[*facts], tell=[*facts])
Deletes and adds many facts in one atomic transaction.
The deletions are performed before the adds.
None can be used as a wildcard in facts in delete.
Does not throw an error when the facts to delete are not found.
Example:
oso.bulk(delete= [ # All `has_role` facts linking User:bob and Repository:anvils will be deleted. { "name": "has_role", "args": [{"type": "User", "id": "bob"}, None, { "type": "Repository", "id": "anvils" }], } ], tell= [ # This fact will be added. { "name": "has_role", "args": [{"type": "User", "id": "bob"}, "maintainer", { "type": "Repository", "id": "anvils" }] } ])
List facts: oso.get(fact)
For Oso Cloud developer accounts, Get calls are limited to 1000 results. If
you have more than 1000 facts, the function will throw an error.
Lists facts that are stored in Oso Cloud. Can be used to check the existence of a particular fact, or used to fetch all facts that have a particular argument:
bob = {"type": "User", "id": "bob"}anvils = {"type": "Repository", "id": "anvils"}# Get one fact:oso.get({"name": "has_role", "args": [bob, "admin", anvils]})# => [{# "name": "has_role",# "args": [# { "type": "User", "id": "bob" },# { "type": "String", "id": "admin" },# { "type": "Repository", "id": "anvils" }# ]# }]# List all role-related facts on the `anvils` repooso.get({"name": "has_role", "args": [None, None, anvils]})# => [# {# "name": "has_role",# "args": [# { "type": "User", "id": "bob" },# { "type": "String", "id": "admin" },# { "type": "Repository", "id": "anvils" }# ]# },# ... other has_role facts# ]
Note that None behaves like a wildcard: passing the fact arguments None, None, anvils means "find all facts where anvils is the third argument,
regardless of other arguments".
Check API
For Oso Cloud developer accounts, * the number of context facts per request is limited to 20; and * the number of records returned is limited to 1000.
Context facts
You may provide an array of context facts as an optional argument to any of the Check API methods. When Oso Cloud performs a check, it will consider these context facts in addition to any other facts you've previously added. Context facts are only used in the API call in which they're provided— they do not persist across requests. Learn more about context facts.
Check a permission: oso.authorize(actor, action, resource)
Determines whether or not an action is allowed, based on a combination of authorization data and policy logic. Example:
alice = {"type": "User", "id": "alice"}anvils_repository = {"type": "Repository", "id": "anvils"}if not oso.authorize(alice, "read", anvils_repository): raise Exception("Action is not allowed")
You may provide a list of context facts as an optional fourth argument to this method. Example:
issue_on_anvils_repository = {"type": "Issue", "id": "anvils-1"}oso.authorize(alice, "read", anvils_repository, [ # a context fact { "name": "has_relation", "args": [issue_on_anvils_repository, "parent", anvils_repository] }])
Check authorized resources: oso.authorize_resources(actor, action, resources)
Returns a subset of resources on which an actor can perform a particular action.
Ordering and duplicates, if any exist, are preserved.
For Oso Cloud developer accounts, the number of input resources is limited to 1000.
Example:
alice = {"type": "User", "id": "alice"}anvils_repository = {"type": "Repository", "id": "anvils"}acme_repository = {"type": "Repository", "id": "acme"}oso.authorize_resources(alice, "read", [anvils_repository, acme_repository])# => [acme_respository]
You may provide a list of context facts as an optional fourth argument to this method. Example:
issue_on_acme_repository = {"type": "Issue", "id": "acme-1"}issue_on_anvils_repository = {"type": "Issue", "id": "anvils-2"}oso.authorize_resources( alice, "read", [anvils_repository, acme_repository], [ # context facts { "name": "has_relation", "args": [issue_on_anvils_repository, "parent", anvils_repository] }, { "name": "has_relation", "args": [issue_on_acme_repository, "parent", acme_repository] }, ])# => [issue_on_acme_repository]
List authorized resources: oso.list(actor, action, resource_type)
Fetches a list of resources on which an actor can perform a particular action. Example:
alice = {"type": "User", "id": "alice"}oso.list(alice, "read", "Repository")# => ["acme"]
You may provide a list of context facts as an optional fourth argument to this method. Example:
anvils_repository = {"type": "Repository", "id": "anvils"}acme_repository = {"type": "Repository", "id": "acme"}issue_on_acme_repository = {"type": "Issue", "id": "acme-1"}issue_on_anvils_repository = {"type": "Issue", "id": "anvils-2"}oso.list( alice, "read", "Issue", [ # context facts { "name": "has_relation", "args": [issue_on_anvils_repository, "parent", anvils_repository] }, { "name": "has_relation", "args": [issue_on_acme_repository, "parent", acme_repository] } ])# => ["acme-1"]
List authorized actions: oso.actions(actor, resource)
Fetches a list of actions which an actor can perform on a particular resource. Example:
alice = {"type": "User", "id": "alice"}acme_repository = {"type": "Repository", "id": "acme"}oso.actions(alice, acme_repository)# => ["read"]
You may provide a list of context facts as an optional third argument to this method. Example:
issue_on_acme_repository = {"type": "Issue", "id": "acme-1"}actions = oso.actions( alice, issue_on_acme_repository, # a context fact [ { "name": "has_relation", "args": [issue_on_acme_repository, "parent", acme_repository] } ])# => ["read"]
Query for anything: oso.query(rule)
Query Oso Cloud for any predicate and any combination of concrete and wildcard arguments.
Unlike oso.get, which only lists facts you've added, you can use oso.query to list derived
information about any rule in your policy.
Example:
# Query for all the repos `User:bob` can `read`oso.query({ "name": "allow", "args": [{"type": "User", "id": "bob"}, "read", {"type": "Repository"}]})# => [# {# "name": "allow",# "args": [{"type": "User", "id": "bob"}, "read", {"type": "Repository", "id": "acme"}],# },# {# "name": "allow",# "args": [{"type": "User", "id": "bob"}, "read", {"type": "Repository", "id": "anvils"}],# }# ]# Query for all the objects `User:admin` can `read`oso.query({ "name": "allow", "args": [{"type": "User", "id": "admin"}, "read", None]})# => [# # `User:admin` can `read` anything# {# "name": "allow",# "args": [{"type": "User", "id": "admin"}, "read", None],# },# ]
Note that None behaves like a wildcard. Passing "allow", None, None, anvils means "find
anyone who can do anything to anvils". None also behaves like a wildcard
in return values from oso.query. Additionally, if you want to query over
all instances of a particular type, pass a dictionary with a "type" key but
no "id" key. For example, "allow", bob, "read", {"type": "Repository"}
will query for all the objects of type "Repository" that bob can read.
Learn more about how to query Oso Cloud.
Distributed Check API
The distributed check API allows you to perform authorization using data that's distributed across Oso Cloud and your own database. When you instantiate the Oso Cloud client, provide the path to the YAML file that specifies how to resolve facts in your database.
oso = Oso( ... data_bindings="path/to/data_bindings.yaml",)
For more information, see the guide on filtering lists with decentralized data.
List authorized resources with distributed data: oso.list_local(actor, action, resource_type, column)
Fetches a filter that can be applied to a database query to return just the resources on which an actor can perform an action. Example with SQLAlchemy:
from sqlalchemy import select, textalice = {"type": "User", "id": "alice"}authorized_issues = session.scalars( select(Issues) .filter(text(oso.list_local(alice, "read", "Issue", "id")))).all()
You may use the SQLAlchemy query builder (opens in a new tab) to combine this authorization filter with other things such as ordering and pagination.
Check a permission with distributed data: oso.authorize_local(actor, action, resource)
Fetches a query that can be run against your database to determine whether an actor can perform an action on a resource. Example with SQLAlchemy:
from sqlalchemy import textalice = {"type": "User", "id": "alice"}swage_issue = {"type": "Issue", "id": "swage"}query = oso.authorize_local(alice, "read", swage_issue)authorized = session.execute(text(query)).scalar()if not authorized: raise Exception("Action is not allowed")
The query will return a single boolean value. The user is authorized to perform the action if that boolean value is true.
Policy API
Update the active policy: oso.policy(policy)
Updates the policy in Oso Cloud. The string passed into this method should be written in Polar. Example:
oso.policy("actor User {}")
This command will run any tests defined in your policy. If one or more of these tests fail, your policy will not be updated.
Get policy metadata: oso.get_policy_metadata()
Returns metadata about the currently active policy. Example:
metadata = oso.get_policy_metadata()print(metadata.resources.keys())# returns ["Organization", "User", "global"]print(metadata.resources["Organization"].roles)# returns ["admin", "member"]
See the Policy Metadata guide for more information on use cases.
Talk to an Oso Engineer
If you'd like to learn more about using Oso Cloud in your app or have any questions about this guide, schedule a 1x1 with an Oso engineer. We're happy to help.