How to implement Open Tracing in gglgen

[Virinchi2595]

The feature list shows that gqlgen supports open tracing but could not find any documentation on implementation details.

Any suggestions on this area will be helpful thanks.

[giautm]

Did you see this package? https://github.com/99designs/gqlgen-contrib/tree/master/gqlopentracing

[Virinchi2595]

Hi @giautm

Thanks for replying

Yes I did see trace.go file

couldn't figure out what to do with it

I am new to golang could you please provide any info or example on how this file can be utilised for tracing

[giautm]

Its gqlgen extension, you can using it via .Use like in this example: https://gqlgen.com/recipes/migration-0.11/

[steebchen]

I am using opencensus and wrote my own simple solution. I wrote it in a short manner but it seems to do a basic job:

package graph

import (
	"context"
	"fmt"

	"github.com/99designs/gqlgen/graphql"
	"go.opencensus.io/trace"
)

// OpenTracing is an opencensus tracer that instruments GraphQL requests with opencensus spans
type OpenTracing struct{}

var _ interface {
	graphql.ResponseInterceptor
	graphql.OperationInterceptor
	graphql.FieldInterceptor
	graphql.HandlerExtension
} = OpenTracing{}

func (t OpenTracing) ExtensionName() string {
	return "open tracing"
}

func (t OpenTracing) Validate(_ graphql.ExecutableSchema) error {
	return nil
}

func (t OpenTracing) InterceptOperation(ctx context.Context, next graphql.OperationHandler) graphql.ResponseHandler {
	op := graphql.GetOperationContext(ctx)
	if op.OperationName == "" {
		op.OperationName = "default"
	}
	ctx, span := trace.StartSpan(ctx, op.OperationName)
	defer span.End()
	return next(ctx)
}

func (t OpenTracing) InterceptField(ctx context.Context, next graphql.Resolver) (res interface{}, err error) {
	field := graphql.GetFieldContext(ctx)
	if field.IsResolver {
		name := fmt.Sprintf("%s.%s", field.Object, field.Field.Name)
		cx, span := trace.StartSpan(ctx, name)
		defer span.End()
		ctx = cx
	}
	return next(ctx)
}

func (t OpenTracing) InterceptResponse(ctx context.Context, next graphql.ResponseHandler) *graphql.Response {
	ctx, span := trace.StartSpan(ctx, "response")
	defer span.End()
	return next(ctx)
}

Then you can just use it:

server.Use(OpenTracing{})