Merge pull request #136 from kjaskiewiczz/rbac

introduce rbac package with utils and middleware

rbac/middleware.go

@@ -0,0 +1,45 @@
+// Copyright 2021 Northern.tech AS
+//
+//    Licensed under the Apache License, Version 2.0 (the "License");
+//    you may not use this file except in compliance with the License.
+//    You may obtain a copy of the License at
+//
+//        http://www.apache.org/licenses/LICENSE-2.0
+//
+//    Unless required by applicable law or agreed to in writing, software
+//    distributed under the License is distributed on an "AS IS" BASIS,
+//    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//    See the License for the specific language governing permissions and
+//    limitations under the License.
+package rbac
+
+import (
+	"github.com/ant0ine/go-json-rest/rest"
+	"github.com/gin-gonic/gin"
+)
+
+func Middleware() gin.HandlerFunc {
+	return func(c *gin.Context) {
+		if scope := ExtractScopeFromHeader(c.Request); scope != nil {
+			ctx := c.Request.Context()
+			ctx = WithContext(ctx, scope)
+			c.Request = c.Request.WithContext(ctx)
+		}
+		return
+	}
+}
+
+type RBACMiddleware struct {
+}
+
+func (mw *RBACMiddleware) MiddlewareFunc(h rest.HandlerFunc) rest.HandlerFunc {
+	return func(w rest.ResponseWriter, r *rest.Request) {
+		if scope := ExtractScopeFromHeader(r.Request); scope != nil {
+			ctx := r.Context()
+			ctx = WithContext(ctx, scope)
+			r.Request = r.WithContext(ctx)
+		}
+
+		h(w, r)
+	}
+}

rbac/rbac.go

@@ -0,0 +1,53 @@
+// Copyright 2021 Northern.tech AS
+//
+//    Licensed under the Apache License, Version 2.0 (the "License");
+//    you may not use this file except in compliance with the License.
+//    You may obtain a copy of the License at
+//
+//        http://www.apache.org/licenses/LICENSE-2.0
+//
+//    Unless required by applicable law or agreed to in writing, software
+//    distributed under the License is distributed on an "AS IS" BASIS,
+//    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//    See the License for the specific language governing permissions and
+//    limitations under the License.
+package rbac
+
+import (
+	"context"
+	"net/http"
+	"strings"
+)
+
+type scopeContextKeyType int
+
+const (
+	scopeContextKey scopeContextKeyType = 0
+	ScopeHeader                         = "X-MEN-RBAC-Inventory-Groups"
+)
+
+type Scope struct {
+	DeviceGroups []string
+}
+
+// FromContext extracts current scope from context.Context
+func FromContext(ctx context.Context) *Scope {
+	val := ctx.Value(scopeContextKey)
+	if v, ok := val.(*Scope); ok {
+		return v
+	}
+	return nil
+}
+
+// WithContext adds scope to context `ctx` and returns the resulting context.
+func WithContext(ctx context.Context, scope *Scope) context.Context {
+	return context.WithValue(ctx, scopeContextKey, scope)
+}
+
+func ExtractScopeFromHeader(r *http.Request) *Scope {
+	groupStr := r.Header.Get(ScopeHeader)
+	if len(groupStr) > 0 {
+		return &Scope{DeviceGroups: strings.Split(groupStr, ",")}
+	}
+	return nil
+}