github.com/yankunsam/loki/v2@v2.6.3-0.20220817130409-389df5235c27/pkg/querier/queryrange/queryrangebase/definitions/interface.go (about)

     1  package definitions
     2  
     3  import (
     4  	"context"
     5  	"net/http"
     6  
     7  	"github.com/gogo/protobuf/proto"
     8  	"github.com/opentracing/opentracing-go"
     9  )
    10  
    11  // Codec is used to encode/decode query range requests and responses so they can be passed down to middlewares.
    12  type Codec interface {
    13  	Merger
    14  	// DecodeRequest decodes a Request from an http request.
    15  	DecodeRequest(_ context.Context, request *http.Request, forwardHeaders []string) (Request, error)
    16  	// DecodeResponse decodes a Response from an http response.
    17  	// The original request is also passed as a parameter this is useful for implementation that needs the request
    18  	// to merge result or build the result correctly.
    19  	DecodeResponse(context.Context, *http.Response, Request) (Response, error)
    20  	// EncodeRequest encodes a Request into an http request.
    21  	EncodeRequest(context.Context, Request) (*http.Request, error)
    22  	// EncodeResponse encodes a Response into an http response.
    23  	EncodeResponse(context.Context, Response) (*http.Response, error)
    24  }
    25  
    26  // Merger is used by middlewares making multiple requests to merge back all responses into a single one.
    27  type Merger interface {
    28  	// MergeResponse merges responses from multiple requests into a single Response
    29  	MergeResponse(...Response) (Response, error)
    30  }
    31  
    32  // Request represents a query range request that can be process by middlewares.
    33  type Request interface {
    34  	// GetStart returns the start timestamp of the request in milliseconds.
    35  	GetStart() int64
    36  	// GetEnd returns the end timestamp of the request in milliseconds.
    37  	GetEnd() int64
    38  	// GetStep returns the step of the request in milliseconds.
    39  	GetStep() int64
    40  	// GetQuery returns the query of the request.
    41  	GetQuery() string
    42  	// GetCachingOptions returns the caching options.
    43  	GetCachingOptions() CachingOptions
    44  	// WithStartEnd clone the current request with different start and end timestamp.
    45  	WithStartEnd(startTime int64, endTime int64) Request
    46  	// WithQuery clone the current request with a different query.
    47  	WithQuery(string) Request
    48  	proto.Message
    49  	// LogToSpan writes information about this request to an OpenTracing span
    50  	LogToSpan(opentracing.Span)
    51  }
    52  
    53  // Response represents a query range response.
    54  type Response interface {
    55  	proto.Message
    56  	// GetHeaders returns the HTTP headers in the response.
    57  	GetHeaders() []*PrometheusResponseHeader
    58  }