Merge pull request #411 from dackroyd/trace-validation-context

Add context to validation tracing

Author: pavelnikolov

graphql.go

@@ -25,16 +25,23 @@ import (
 // resolver, then the schema can not be executed, but it may be inspected (e.g. with ToJSON).
 func ParseSchema(schemaString string, resolver interface{}, opts ...SchemaOpt) (*Schema, error) {
 	s := &Schema{
-		schema:           schema.New(),
-		maxParallelism:   10,
-		tracer:           trace.OpenTracingTracer{},
-		validationTracer: trace.NoopValidationTracer{},
-		logger:           &log.DefaultLogger{},
+		schema:         schema.New(),
+		maxParallelism: 10,
+		tracer:         trace.OpenTracingTracer{},
+		logger:         &log.DefaultLogger{},
 	}
 	for _, opt := range opts {
 		opt(s)
 	}
 
+	if s.validationTracer == nil {
+		if tracer, ok := s.tracer.(trace.ValidationTracerContext); ok {
+			s.validationTracer = tracer
+		} else {
+			s.validationTracer = &validationBridgingTracer{tracer: trace.NoopValidationTracer{}}
+		}
+	}
+
 	if err := s.schema.Parse(schemaString, s.useStringDescriptions); err != nil {
 		return nil, err
 	}
@@ -68,7 +75,7 @@ type Schema struct {
 	maxDepth                 int
 	maxParallelism           int
 	tracer                   trace.Tracer
-	validationTracer         trace.ValidationTracer
+	validationTracer         trace.ValidationTracerContext
 	logger                   log.Logger
 	useStringDescriptions    bool
 	disableIntrospection     bool
@@ -117,9 +124,10 @@ func Tracer(tracer trace.Tracer) SchemaOpt {
 }
 
 // ValidationTracer is used to trace validation errors. It defaults to trace.NoopValidationTracer.
+// Deprecated: context is needed to support tracing correctly. Use a Tracer which implements trace.ValidationTracerContext.
 func ValidationTracer(tracer trace.ValidationTracer) SchemaOpt {
 	return func(s *Schema) {
-		s.validationTracer = tracer
+		s.validationTracer = &validationBridgingTracer{tracer: tracer}
 	}
 }
 
@@ -186,7 +194,7 @@ func (s *Schema) exec(ctx context.Context, queryString string, operationName str
 		return &Response{Errors: []*errors.QueryError{qErr}}
 	}
 
-	validationFinish := s.validationTracer.TraceValidation()
+	validationFinish := s.validationTracer.TraceValidation(ctx)
 	errs := validation.Validate(s.schema, doc, variables, s.maxDepth)
 	validationFinish(errs)
 	if len(errs) != 0 {
@@ -272,6 +280,14 @@ func (s *Schema) validateSchema() error {
 	return nil
 }
 
+type validationBridgingTracer struct {
+	tracer trace.ValidationTracer
+}
+
+func (t *validationBridgingTracer) TraceValidation(context.Context) trace.TraceValidationFinishFunc {
+	return t.tracer.TraceValidation()
+}
+
 func validateRootOp(s *schema.Schema, name string, mandatory bool) error {
 	t, ok := s.EntryPoints[name]
 	if !ok {

subscriptions.go

@@ -36,7 +36,7 @@ func (s *Schema) subscribe(ctx context.Context, queryString string, operationNam
 		return sendAndReturnClosed(&Response{Errors: []*qerrors.QueryError{qErr}})
 	}
 
-	validationFinish := s.validationTracer.TraceValidation()
+	validationFinish := s.validationTracer.TraceValidation(ctx)
 	errs := validation.Validate(s.schema, doc, variables, s.maxDepth)
 	validationFinish(errs)
 	if len(errs) != 0 {

trace/trace.go

@@ -67,6 +67,22 @@ func (OpenTracingTracer) TraceField(ctx context.Context, label, typeName, fieldN
 	}
 }
 
+func (OpenTracingTracer) TraceValidation(ctx context.Context) TraceValidationFinishFunc {
+	span, _ := opentracing.StartSpanFromContext(ctx, "Validate Query")
+
+	return func(errs []*errors.QueryError) {
+		if len(errs) > 0 {
+			msg := errs[0].Error()
+			if len(errs) > 1 {
+				msg += fmt.Sprintf(" (and %d more errors)", len(errs)-1)
+			}
+			ext.Error.Set(span, true)
+			span.SetTag("graphql.error", msg)
+		}
+		span.Finish()
+	}
+}
+
 func noop(*errors.QueryError) {}
 
 type NoopTracer struct{}

trace/validation_trace.go

@@ -1,17 +1,25 @@
 package trace
 
 import (
+	"context"
+
 	"github.com/graph-gophers/graphql-go/errors"
 )
 
 type TraceValidationFinishFunc = TraceQueryFinishFunc
 
+// Deprecated: use ValidationTracerContext.
 type ValidationTracer interface {
 	TraceValidation() TraceValidationFinishFunc
 }
 
+type ValidationTracerContext interface {
+	TraceValidation(ctx context.Context) TraceValidationFinishFunc
+}
+
 type NoopValidationTracer struct{}
 
+// Deprecated: use a Tracer which implements ValidationTracerContext.
 func (NoopValidationTracer) TraceValidation() TraceValidationFinishFunc {
 	return func(errs []*errors.QueryError) {}
 }