github.com/cloudwego/kitex@v0.9.0/pkg/utils/contextmap/contextmap.go (about)

     1  /*
     2   * Copyright 2023 CloudWeGo Authors
     3   *
     4   * Licensed under the Apache License, Version 2.0 (the "License");
     5   * you may not use this file except in compliance with the License.
     6   * You may obtain a copy of the License at
     7   *
     8   *     http://www.apache.org/licenses/LICENSE-2.0
     9   *
    10   * Unless required by applicable law or agreed to in writing, software
    11   * distributed under the License is distributed on an "AS IS" BASIS,
    12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13   * See the License for the specific language governing permissions and
    14   * limitations under the License.
    15   */
    16  
    17  package contextmap
    18  
    19  import (
    20  	"context"
    21  	"sync"
    22  )
    23  
    24  type contextMapKey struct{}
    25  
    26  // WithContextMap returns a new context that carries a sync.Map
    27  // It's useful if you want to share a sync.Map between middlewares, especially for
    28  // Middleware and RecvMiddleware/SendMiddleware, since in recv/send middlewares,
    29  // we can only get the stream.Context() which is a fixed node in the context tree.
    30  //
    31  // Note: it's not added to context by default, and you should add it yourself if needed.
    32  func WithContextMap(ctx context.Context) context.Context {
    33  	return context.WithValue(ctx, contextMapKey{}, &sync.Map{})
    34  }
    35  
    36  // GetContextMap returns the sync.Map in the given context
    37  func GetContextMap(ctx context.Context) (m *sync.Map, ok bool) {
    38  	if ctx != nil {
    39  		m, ok = ctx.Value(contextMapKey{}).(*sync.Map)
    40  	}
    41  	return
    42  }