options.go

Documentation: github.com/grpc-ecosystem/go-grpc-middleware/tracing/opentracing

     1  // Copyright 2017 Michal Witkowski. All Rights Reserved.
     2  // See LICENSE for licensing terms.
     3  
     4  package grpc_opentracing
     5  
     6  import (
     7  	"context"
     8  
     9  	"github.com/opentracing/opentracing-go"
    10  )
    11  
    12  var (
    13  	defaultOptions = &options{
    14  		filterOutFunc: nil,
    15  		tracer:        nil,
    16  	}
    17  )
    18  
    19  // FilterFunc allows users to provide a function that filters out certain methods from being traced.
    20  //
    21  // If it returns false, the given request will not be traced.
    22  type FilterFunc func(ctx context.Context, fullMethodName string) bool
    23  
    24  // UnaryRequestHandlerFunc is a custom request handler
    25  type UnaryRequestHandlerFunc func(span opentracing.Span, req interface{})
    26  
    27  // OpNameFunc is a func that allows custom operation names instead of the gRPC method.
    28  type OpNameFunc func(method string) string
    29  
    30  type options struct {
    31  	filterOutFunc           FilterFunc
    32  	tracer                  opentracing.Tracer
    33  	traceHeaderName         string
    34  	unaryRequestHandlerFunc UnaryRequestHandlerFunc
    35  	opNameFunc              OpNameFunc
    36  }
    37  
    38  func evaluateOptions(opts []Option) *options {
    39  	optCopy := &options{}
    40  	*optCopy = *defaultOptions
    41  	for _, o := range opts {
    42  		o(optCopy)
    43  	}
    44  	if optCopy.tracer == nil {
    45  		optCopy.tracer = opentracing.GlobalTracer()
    46  	}
    47  	if optCopy.traceHeaderName == "" {
    48  		optCopy.traceHeaderName = "uber-trace-id"
    49  	}
    50  	return optCopy
    51  }
    52  
    53  type Option func(*options)
    54  
    55  // WithFilterFunc customizes the function used for deciding whether a given call is traced or not.
    56  func WithFilterFunc(f FilterFunc) Option {
    57  	return func(o *options) {
    58  		o.filterOutFunc = f
    59  	}
    60  }
    61  
    62  // WithTraceHeaderName customizes the trace header name where trace metadata passed with requests.
    63  // Default one is `uber-trace-id`
    64  func WithTraceHeaderName(name string) Option {
    65  	return func(o *options) {
    66  		o.traceHeaderName = name
    67  	}
    68  }
    69  
    70  // WithTracer sets a custom tracer to be used for this middleware, otherwise the opentracing.GlobalTracer is used.
    71  func WithTracer(tracer opentracing.Tracer) Option {
    72  	return func(o *options) {
    73  		o.tracer = tracer
    74  	}
    75  }
    76  
    77  // WithUnaryRequestHandlerFunc sets a custom handler for the request
    78  func WithUnaryRequestHandlerFunc(f UnaryRequestHandlerFunc) Option {
    79  	return func(o *options) {
    80  		o.unaryRequestHandlerFunc = f
    81  	}
    82  }
    83  
    84  // WithOpName customizes the trace Operation name
    85  func WithOpName(f OpNameFunc) Option {
    86  	return func(o *options) {
    87  		o.opNameFunc = f
    88  	}
    89  }
    90
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