Gin-Keycloak

Gin-Keycloak is specially made for Gin Framework users who also want to use Keycoak. This Project was inspired by zalando's gin-oauth

Project Context and Features

When it comes to choosing a Go framework, there's a lot of confusion about what to use. The scene is very fragmented, and detailed comparisons of different frameworks are still somewhat rare. Meantime, how to handle dependencies and structure projects are big topics in the Go community. We've liked using Gin for its speed, accessibility, and usefulness in developing microservice architectures. In creating Gin-OAuth2, we wanted to take fuller advantage of Gin's capabilities and help other devs do likewise.

Gin-Keycloak is expressive, flexible, and very easy to use. It allows you to:

do OAuth2 authorization based on the JWT Token
create router groups to place Keycloak authorization on top, using HTTP verbs and passing them
more easily decouple services by promoting a "say what to do, not how to do it" approach
configure your REST API directly in the code (see the "Usage" example below)
write your own authorization functions

Requirements

Gin
An Keycloak Token provider

Gin-Keycloak uses the following Go packages as dependencies:

Installation

Assuming you've installed Go and Gin, run this:

go get github.com/tbaehler/gin-keycloak

Usage

Authentication-Based Access

With this function you just check if user is authenticated. Therefore there is no need for AccessTuple unlike next two access types.

Gin middlewares you use:

router := gin.New()
router.Use(ginglog.Logger(3 * time.Second))
router.Use(ginkeycloak.RequestLogger([]string{"uid"}, "data"))
router.Use(gin.Recovery())

A Keycloakconfig

var sbbEndpoint = ginkeycloak.KeycloakConfig{
    Url:  "https://keycloack.domain.ch/",
    Realm: "Your Realm",
}

Lastly, define which type of access you grant to the defined team. We'll use a router group again:

privateGroup := router.Group("/api/privateGroup")
privateGroup.Use(ginkeycloak.Auth(ginkeycloak.GroupCheck(GRANTED_ROLE), keycloakconfig))
privateGroup.GET("/", func(c *gin.Context) {
	....
})

Once again, you can use curl to test:

    curl -H "Authorization: Bearer $TOKEN" http://localhost:8081/api/privateGroup/
    {"message":"Hello from private to sszuecs member of teapot"}

Uid-Based Access

First, define your access triples to identify who has access to a given resource. This snippet shows how to grant resource access to two hypothetical employees:

//from ginkeycloak package
// AccessTuple is the type defined for use in AccessTuples.
  
        type AccessTuple struct {
       	    Service string
       	    Role    string
       	    Uid     string
        }
    
var GRANTED_USERS  = []ginkeycloak.AccessTuple{{Uid: "domain\user1"}}

Next, define which Gin middlewares you use. The third line in this snippet is a basic audit log:

router := gin.New()
router.Use(ginglog.Logger(3 * time.Second))
router.Use(ginkeycloak.RequestLogger([]string{"uid"}, "data"))
router.Use(gin.Recovery())

Finally, define which type of access you grant to the defined users. We'll use a router group, so that we can add a bunch of router paths and HTTP verbs:

privateUser := router.Group("/api/privateUser")
privateUser.Use(ginkeycloak.Auth(ginkeycloak.UidCheck(USERS), keycloakConfig))
privateUser.GET("/", func(c *gin.Context) {
	....
})

Testing

To test, you can use curl:

    curl -H "Authorization: Bearer $TOKEN" http://localhost:8081/api/privateUser/
    {"message":"Hello from private for users to Sandor Szücs"}

Role-Based Access

As with Uid-based access, define your access triples to identify who has access to a given resource. With this snippet, you can grant resource access to an entire team instead of individuals:

var GRANTED_ROLE  = []ginkeycloak.AccessTuple{
    {Service: "keycloak-service", Role: "keycloak-role"},
}

Now define which Gin middlewares you use:

router := gin.New()
router.Use(ginglog.Logger(3 * time.Second))
router.Use(ginkeycloak.RequestLogger([]string{"uid"}, "data"))
router.Use(gin.Recovery())