github.com/m3db/m3@v1.5.0/src/query/storage/prometheus/context.go (about)

     1  // Copyright (c) 2020 Uber Technologies, Inc.
     2  //
     3  // Permission is hereby granted, free of charge, to any person obtaining a copy
     4  // of this software and associated documentation files (the "Software"), to deal
     5  // in the Software without restriction, including without limitation the rights
     6  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     7  // copies of the Software, and to permit persons to whom the Software is
     8  // furnished to do so, subject to the following conditions:
     9  //
    10  // The above copyright notice and this permission notice shall be included in
    11  // all copies or substantial portions of the Software.
    12  //
    13  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    14  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    15  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    16  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    17  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    18  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    19  // THE SOFTWARE.
    20  
    21  package prometheus
    22  
    23  import (
    24  	"context"
    25  	"errors"
    26  
    27  	"github.com/m3db/m3/src/query/block"
    28  	"github.com/m3db/m3/src/query/storage"
    29  )
    30  
    31  // ContextKey is the context key type.
    32  type ContextKey string
    33  
    34  const (
    35  	// FetchOptionsContextKey is the context key for fetch options.
    36  	FetchOptionsContextKey ContextKey = "fetch-options"
    37  
    38  	// BlockResultMetadataFnKey is the context key for a function to receive block metadata results.
    39  	BlockResultMetadataFnKey ContextKey = "block-meta-result-fn"
    40  )
    41  
    42  // RemoteReadFlags is a set of flags for storage remote read requests.
    43  type RemoteReadFlags struct {
    44  	Limited bool
    45  }
    46  
    47  func fetchOptions(ctx context.Context) (*storage.FetchOptions, error) {
    48  	fetchOptions := ctx.Value(FetchOptionsContextKey)
    49  	if f, ok := fetchOptions.(*storage.FetchOptions); ok {
    50  		return f, nil
    51  	}
    52  	return nil, errors.New("fetch options not available")
    53  }
    54  
    55  func resultMetadataReceiveFn(ctx context.Context) (func(m block.ResultMetadata), error) {
    56  	value := ctx.Value(BlockResultMetadataFnKey)
    57  	if v, ok := value.(func(m block.ResultMetadata)); ok {
    58  		return v, nil
    59  	}
    60  	return nil, errors.New("block result metadata not available")
    61  }