OAuth: Support role mapping for GitLab OAuth (#30025)

* Support `role_attribute_path` for GitLab OAuth

Allow role mapping for GitLab accounts.

Example:

  [auth.gitlab]
  role_attribute_path = is_admin && 'Admin' || 'Viewer'

* Support `role_attribute_path` for GitLab OAuth

Allow role mapping for GitLab accounts.

Example:

  [auth.gitlab]
  role_attribute_path = is_admin && 'Admin' || 'Viewer'

* docs: add docs for role_attribute_path

* Apply suggestions from code review

Co-authored-by: Peter Leitzen <splattael@users.noreply.github.com>

* docs: update example

example should suggest a full configuration

* Apply suggestions from code review

Co-authored-by: Marcus Efraimsson <marcus.efraimsson@gmail.com>

* Apply suggestions from code review

Co-authored-by: Fiona Artiaga <89225282+GrafanaWriter@users.noreply.github.com>

* docs: add suggestions from tech writers

Co-authored-by: Henry Sachs <Henry.Sachs@deutschebahn.com>
Co-authored-by: Henry Sachs <henrysachs@gmail.com>
Co-authored-by: Marcus Efraimsson <marcus.efraimsson@gmail.com>
Co-authored-by: Fiona Artiaga <89225282+GrafanaWriter@users.noreply.github.com>

docs/sources/auth/gitlab.md

@@ -26,10 +26,10 @@ instance, if you access Grafana at `http://203.0.113.31:3000`, you should use
 http://203.0.113.31:3000/login/gitlab
 ```
 
-Finally, select _read_api_ as the _Scope_ and submit the form. Note that if you're
+Finally, select _read_api_as the_Scope_and submit the form. Note that if you're
 not going to use GitLab groups for authorization (i.e. not setting
-`allowed_groups`, see below), you can select _read_user_ instead of _read_api_ as
+`allowed_groups`, see below), you can select_read_user_ instead of _read_api_as
-the _Scope_, thus giving a more restricted access to your GitLab API.
+the_Scope_, thus giving a more restricted access to your GitLab API.
 
 You'll get an _Application Id_ and a _Secret_ in return; we'll call them
 `GITLAB_APPLICATION_ID` and `GITLAB_SECRET` respectively for the rest of this
@@ -94,8 +94,8 @@ display name, especially if the display name contains spaces or special
 characters. Make sure you always use the group or subgroup name as it appears
 in the URL of the group or subgroup.
 
-Here's a complete example with `allow_sign_up` enabled, and access limited to
+Here's a complete example with `allow_sign_up` enabled, with access limited to
-the `example` and `foo/bar` groups:
+the `example` and `foo/bar` groups. The example also promotes all GitLab Admins to Grafana Admins:
 
 ```ini
 [auth.gitlab]
@@ -103,13 +103,28 @@ enabled = true
 allow_sign_up = true
 client_id = GITLAB_APPLICATION_ID
 client_secret = GITLAB_SECRET
-scopes = api
+scopes = read_api
 auth_url = https://gitlab.com/oauth/authorize
 token_url = https://gitlab.com/oauth/token
 api_url = https://gitlab.com/api/v4
 allowed_groups = example, foo/bar
+role_attribute_path = is_admin && 'Admin' || 'Viewer'
 ```
 
+### Map roles
+
+You can use GitLab OAuth to map roles. During mapping, Grafana checks for the presence of a role using the [JMESPath](http://jmespath.org/examples.html) specified via the `role_attribute_path` configuration option.
+
+For the path lookup, Grafana uses JSON obtained from querying GitLab's API [`/api/v4/user`](https://docs.gitlab.com/ee/api/users.html#list-current-user-for-normal-users) endpoint. The result of evaluating the `role_attribute_path` JMESPath expression must be a valid Grafana role, for example, `Viewer`, `Editor` or `Admin`. For more information about roles and permissions in Grafana, refer to [Organization roles]({{< relref "../permissions/organization_roles.md" >}}).
+
+An example Query could look like the following:
+
+```bash
+role_attribute_path = is_admin && 'Admin' || 'Viewer'
+```
+
+This allows every GitLab Admin to be an Admin in Grafana.
+
 ### Team Sync (Enterprise only)
 
 > Only available in Grafana Enterprise v6.4+

pkg/login/social/gitlab_oauth.go

@@ -15,6 +15,7 @@ type SocialGitlab struct {
 	*SocialBase
 	allowedGroups     []string
 	apiUrl            string
+	roleAttributePath string
 }
 
 func (s *SocialGitlab) Type() int {
@@ -114,12 +115,18 @@ func (s *SocialGitlab) UserInfo(client *http.Client, token *oauth2.Token) (*Basi
 
 	groups := s.GetGroups(client)
 
+	role, err := s.extractRole(response.Body)
+	if err != nil {
+		s.log.Error("Failed to extract role", "error", err)
+	}
+
 	userInfo := &BasicUserInfo{
 		Id:     fmt.Sprintf("%d", data.Id),
 		Name:   data.Name,
 		Login:  data.Username,
 		Email:  data.Email,
 		Groups: groups,
+		Role:   role,
 	}
 
 	if !s.IsGroupMember(groups) {
@@ -128,3 +135,16 @@ func (s *SocialGitlab) UserInfo(client *http.Client, token *oauth2.Token) (*Basi
 
 	return userInfo, nil
 }
+
+func (s *SocialGitlab) extractRole(rawJSON []byte) (string, error) {
+	if s.roleAttributePath == "" {
+		return "", nil
+	}
+
+	role, err := s.searchJSONForStringAttr(s.roleAttributePath, rawJSON)
+
+	if err != nil {
+		return "", err
+	}
+	return role, nil
+}

pkg/login/social/social.go

@@ -129,6 +129,7 @@ func ProvideService(cfg *setting.Cfg) *SocialService {
 				SocialBase:        newSocialBase(name, &config, info),
 				apiUrl:            info.ApiUrl,
 				allowedGroups:     util.SplitString(sec.Key("allowed_groups").String()),
+				roleAttributePath: info.RoleAttributePath,
 			}
 		}