github.com/hasnat/dolt/go@v0.0.0-20210628190320-9eb5d843fbb7/libraries/utils/tracing/tracing.go (about)

     1  // Copyright 2020 Dolthub, Inc.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package tracing
    16  
    17  import (
    18  	"context"
    19  
    20  	"github.com/opentracing/opentracing-go"
    21  )
    22  
    23  // Called throughout dolt to get the tracer. Default implementation returns
    24  // opentracing.GlobalTracer(), but another implementation could be installed to
    25  // return a context-specific tracer.
    26  var Tracer func(ctx context.Context) opentracing.Tracer
    27  
    28  func init() {
    29  	Tracer = func(ctx context.Context) opentracing.Tracer {
    30  		return opentracing.GlobalTracer()
    31  	}
    32  }
    33  
    34  // Start a new span, named `name`, as a child of the current span associated
    35  // with `ctx`. Starts a root span if there is no Span associated with `ctx`.
    36  // Returns the newly created Span and a new `ctx` associated with the Span.
    37  func StartSpan(ctx context.Context, name string) (opentracing.Span, context.Context) {
    38  	parentSpan := opentracing.SpanFromContext(ctx)
    39  	var opts []opentracing.StartSpanOption
    40  	if parentSpan != nil {
    41  		opts = append(opts, opentracing.ChildOf(parentSpan.Context()))
    42  	}
    43  	span := Tracer(ctx).StartSpan(name, opts...)
    44  	ctx = opentracing.ContextWithSpan(ctx, span)
    45  	return span, ctx
    46  }