Casbin
News: Casbin is also started to port to Java, contribution is welcomed. See: https://github.com/casbin/jcasbin
Casbin is a powerful and efficient open-source access control library for Golang projects. It provides support for enforcing authorization based on various access control models.
If you want to easily add authentication and authorization to your Go projects, feel free to check out Auth0's Go SDK and free plan at auth0.com/overview
Table of contents
- Supported models
- How it works?
- Features
- Installation
- Documentation
- Get started
- Policy management
- Policy persistence
- Policy consistence between multiple nodes
- Role manager
- Multi-threading
- Benchmarks
- Examples
- How to use Casbin as a service?
- Our adopters
Supported models
- ACL (Access Control List)
- ACL with superuser
- ACL without users: especially useful for systems that don't have authentication or user log-ins.
- ACL without resources: some scenarios may target for a type of resources instead of an individual resource by using permissions like
write-article
,read-log
. It doesn't control the access to a specific article or log. - RBAC (Role-Based Access Control)
- RBAC with resource roles: both users and resources can have roles (or groups) at the same time.
- RBAC with domains/tenants: users can have different role sets for different domains/tenants.
- ABAC (Attribute-Based Access Control): syntax sugar like
resource.Owner
can be used to get the attribute for a resource. - RESTful: supports paths like
/res/*
,/res/:id
and HTTP methods likeGET
,POST
,PUT
,DELETE
. - Deny-override: both allow and deny authorizations are supported, deny overrides the allow.
- Priority: the policy rules can be prioritized like firewall rules.
How it works?
In Casbin, an access control model is abstracted into a CONF file based on the PERM metamodel (Policy, Effect, Request, Matchers). So switching or upgrading the authorization mechanism for a project is just as simple as modifying a configuration. You can customize your own access control model by combining the available models. For example, you can get RBAC roles and ABAC attributes together inside one model and share one set of policy rules.
The most basic and simplest model in Casbin is ACL. ACL's model CONF is:
# Request definition
[request_definition]
r = sub, obj, act
# Policy definition
[policy_definition]
p = sub, obj, act
# Policy effect
[policy_effect]
e = some(where (p.eft == allow))
# Matchers
[matchers]
m = r.sub == p.sub && r.obj == p.obj && r.act == p.act
An example policy for ACL model is like:
p, alice, data1, read
p, bob, data2, write
It means:
- alice can read data1
- bob can write data2
Features
What Casbin does:
- enforce the policy in the classic
{subject, object, action}
form or a customized form as you defined, both allow and deny authorizations are supported. - handle the storage of the access control model and its policy.
- manage the role-user mappings and role-role mappings (aka role hierarchy in RBAC).
- support built-in superuser like
root
oradministrator
. A superuser can do anything without explict permissions. - multiple built-in operators to support the rule matching. For example,
keyMatch
can map a resource key/foo/bar
to the pattern/foo*
.
What Casbin does NOT do:
- authentication (aka verify
username
andpassword
when a user logs in) - manage the list of users or roles. I believe it's more convenient for the project itself to manage these entities. Users usually have their passwords, and Casbin is not designed as a password container. However, Casbin stores the user-role mapping for the RBAC scenario.
Installation
go get github.com/casbin/casbin
Documentation
See: Our Wiki
3-rd party tutorials
- Basic Role-Based HTTP Authorization in Go with Casbin
- Using Casbin with Beego: 1. Get started and test (in Chinese)
- Using Casbin with Beego: 2. Policy storage (in Chinese)
Get started
-
New a Casbin enforcer with a model file and a policy file:
e := casbin.NewEnforcer("path/to/model.conf", "path/to/policy.csv")
Note: you can also initialize an enforcer with policy in DB instead of file, see Persistence section for details.
-
Add an enforcement hook into your code right before the access happens:
sub := "alice" // the user that wants to access a resource. obj := "data1" // the resource that is going to be accessed. act := "read" // the operation that the user performs on the resource. if e.Enforce(sub, obj, act) == true { // permit alice to read data1 } else { // deny the request, show an error }
-
Besides the static policy file, Casbin also provides API for permission management at run-time. For example, You can get all the roles assigned to a user as below:
roles := e.GetRoles("alice")
See Policy management APIs for more usage.
- Please refer to the
_test.go
files for more usage.
Policy management
Casbin provides two sets of APIs to manage permissions:
- Management API: the primitive API that provides full support for Casbin policy management. See here for examples.
- RBAC API: a more friendly API for RBAC. This API is a subset of Management API. The RBAC users could use this API to simplify the code. See here for examples.
We also provide a web-based UI for model management and policy management:
Policy persistence
In Casbin, the policy storage is implemented as an adapter (aka middleware for Casbin). To keep light-weight, we don't put adapter code in the main library. A complete list of Casbin adapters is provided as below. Any 3rd-party contribution on a new adapter is welcomed, please inform us and I will put it in this list:)
Adapter | Type | Author | Description |
---|---|---|---|
File Adapter (built-in) | File | Casbin | Persistence for .CSV (Comma-Separated Values) files |
Xorm Adapter | ORM | Casbin | MySQL, PostgreSQL, TiDB, SQLite, SQL Server, Oracle are supported by Xorm |
Gorm Adapter | ORM | Casbin | MySQL, PostgreSQL, Sqlite3, SQL Server are supported by Gorm |
Beego ORM Adapter | ORM | Casbin | MySQL, PostgreSQL, Sqlite3 are supported by Beego ORM |
MongoDB Adapter | NoSQL | Casbin | Persistence for MongoDB |
Cassandra Adapter | NoSQL | Casbin | Persistence for Apache Cassandra DB |
Consul Adapter | KV store | @ankitm123 | Persistence for HashiCorp Consul |
Redis Adapter | KV store | Casbin | Persistence for Redis |
Protobuf Adapter | Stream | Casbin | Persistence for Google Protocol Buffers |
JSON Adapter | Stream | Casbin | Persistence for JSON |
RQLite Adapter | SQL | EDOMO Systems | Persistence for RQLite |
PostgreSQL Adapter | SQL | Going | Persistence for PostgreSQL |
RethinkDB Adapter | NoSQL | @adityapandey9 | Persistence for RethinkDB |
DynamoDB Adapter | NoSQL | HOOQ | Persistence for Amazon DynamoDB |
For details of adapters, please refer to the documentation: https://github.com/casbin/casbin/wiki/Policy-persistence
Policy consistence between multiple nodes
We support to use etcd to keep consistence between multiple Casbin enforcer instances. Please see: https://github.com/casbin/etcd-watcher
Role manager
We support different implementations of a RBAC role manager. The currently supported adapters are:
Role manager | Description |
---|---|
Default role manager | Supports role hierarchy |
Session role manager | Supports role hierarchy, time-range-based sessions |
For developers: all role managers must implement the RoleManager interface.
To use a custom role manager implementation:
type myCustomRoleManager struct {} // assumes the type satisfies the RoleManager interface
func newRoleManager() rbac.RoleManagerConstructor {
return func() rbac.RoleManager {
return &myCustomRoleManager{}
}
}
e := casbin.NewEnforcer("path/to/model.conf", "path/to/policy.csv")
e.SetRoleManager(newRoleManager())
Multi-threading
If you use Casbin in a multi-threading manner, you can use the synchronized wrapper of the Casbin enforcer: https://github.com/casbin/casbin/blob/master/enforcer_synced.go.
It also supports the AutoLoad
feature, which means the Casbin enforcer will automatically load the latest policy rules from DB if it has changed. Call StartAutoLoadPolicy()
to start automatically loading policy periodically and call StopAutoLoadPolicy()
to stop it.
Benchmarks
The overhead of policy enforcement is benchmarked in model_b_test.go. The testbed is:
Intel(R) Core(TM) i7-6700HQ CPU @ 2.60GHz, 2601 Mhz, 4 Core(s), 8 Logical Processor(s)
The benchmarking result of go test -bench=. -benchmem
is as follows (op = an Enforce()
call, ms = millisecond, KB = kilo bytes):
Test case | Size | Time overhead | Memory overhead |
---|---|---|---|
ACL | 2 rules (2 users) | 0.015493 ms/op | 5.649 KB |
RBAC | 5 rules (2 users, 1 role) | 0.021738 ms/op | 7.522 KB |
RBAC (small) | 1100 rules (1000 users, 100 roles) | 0.164309 ms/op | 80.620 KB |
RBAC (medium) | 11000 rules (10000 users, 1000 roles) | 2.258262 ms/op | 765.152 KB |
RBAC (large) | 110000 rules (100000 users, 10000 roles) | 23.916776 ms/op | 7.606 MB |
RBAC with resource roles | 6 rules (2 users, 2 roles) | 0.021146 ms/op | 7.906 KB |
RBAC with domains/tenants | 6 rules (2 users, 1 role, 2 domains) | 0.032696 ms/op | 10.755 KB |
ABAC | 0 rule (0 user) | 0.007510 ms/op | 2.328 KB |
RESTful | 5 rules (3 users) | 0.045398 ms/op | 91.774 KB |
Deny-override | 6 rules (2 users, 1 role) | 0.023281 ms/op | 8.370 KB |
Priority | 9 rules (2 users, 2 roles) | 0.016389 ms/op | 5.313 KB |
Examples
Model | Model file | Policy file |
---|---|---|
ACL | basic_model.conf | basic_policy.csv |
ACL with superuser | basic_model_with_root.conf | basic_policy.csv |
ACL without users | basic_model_without_users.conf | basic_policy_without_users.csv |
ACL without resources | basic_model_without_resources.conf | basic_policy_without_resources.csv |
RBAC | rbac_model.conf | rbac_policy.csv |
RBAC with resource roles | rbac_model_with_resource_roles.conf | rbac_policy_with_resource_roles.csv |
RBAC with domains/tenants | rbac_model_with_domains.conf | rbac_policy_with_domains.csv |
ABAC | abac_model.conf | N/A |
RESTful | keymatch_model.conf | keymatch_policy.csv |
Deny-override | rbac_model_with_deny.conf | rbac_policy_with_deny.csv |
Priority | priority_model.conf | priority_policy.csv |
How to use Casbin as a service?
- Go-Simple-API-Gateway: A simple API gateway written by golang, supports for authentication and authorization
- Casbin Server: Casbin as a Service via RESTful, only exposed permission checking API
- middleware-acl: RESTful access control middleware based on Casbin
Our adopters
Web frameworks
- Beego: An open-source, high-performance web framework for Go, via built-in plugin: plugins/authz
- Caddy: Fast, cross-platform HTTP/2 web server with automatic HTTPS, via plugin: caddy-authz
- Gin: A HTTP web framework featuring a Martini-like API with much better performance, via plugin: authz
- Revel: A high productivity, full-stack web framework for the Go language, via plugin: auth/casbin
- Echo: High performance, minimalist Go web framework, via plugin: echo-authz (thanks to @xqbumu)
- Iris: The fastest web framework for Go in (THIS) Earth. HTTP/2 Ready-To-GO, via plugin: casbin (thanks to @hiveminded)
- Negroni: Idiomatic HTTP Middleware for Golang, via plugin: negroni-authz
- Tango: Micro & pluggable web framework for Go, via plugin: authz
- Chi: A lightweight, idiomatic and composable router for building HTTP services, via plugin: chi-authz
- Macaron: A high productive and modular web framework in Go, via plugin: authz
- DotWeb: Simple and easy go web micro framework, via plugin: authz
- Baa: An express Go web framework with routing, middleware, dependency injection and http context, via plugin: authz
Others
- Intel RMD: Intel's resource management daemon, via direct integration, see: policy rules
- Docker: The world's leading software container platform, via plugin: casbin-authz-plugin (recommended by Docker)
- Gobis: Orange's lightweight API Gateway written in go, via plugin: casbin
- Zenpress: A CMS system written in Golang, via direct integration
- EngineerCMS: A CMS to manage knowledge for engineers, via direct integration, see: policy rules (in SQLite)
- Cyber Auth API: A Golang authentication API project, via direct integration, see: policy rules
License
This project is licensed under the Apache 2.0 license.
Contact
If you have any issues or feature requests, please contact us. PR is welcomed.
- https://github.com/casbin/casbin/issues
- hsluoyz@gmail.com
- Tencent QQ group: 546057381