Merge pull request #105 from kevpar/etw-activityid

Support ETW activity ID

internal/etw/eventopt.go

@@ -1,9 +1,20 @@
 package etw
 
+import (
+	"golang.org/x/sys/windows"
+)
+
+type eventOptions struct {
+	descriptor        *EventDescriptor
+	activityID        *windows.GUID
+	relatedActivityID *windows.GUID
+	tags              uint32
+}
+
 // EventOpt defines the option function type that can be passed to
 // Provider.WriteEvent to specify general event options, such as level and
 // keyword.
-type EventOpt func(*EventDescriptor, *uint32)
+type EventOpt func(options *eventOptions)
 
 // WithEventOpts returns the variadic arguments as a single slice.
 func WithEventOpts(opts ...EventOpt) []EventOpt {
@@ -12,23 +23,35 @@ func WithEventOpts(opts ...EventOpt) []EventOpt {
 
 // WithLevel specifies the level of the event to be written.
 func WithLevel(level Level) EventOpt {
-	return func(descriptor *EventDescriptor, tags *uint32) {
+	return func(options *eventOptions) {
-		descriptor.Level = level
+		options.descriptor.Level = level
 	}
 }
 
 // WithKeyword specifies the keywords of the event to be written. Multiple uses
 // of this option are OR'd together.
 func WithKeyword(keyword uint64) EventOpt {
-	return func(descriptor *EventDescriptor, tags *uint32) {
+	return func(options *eventOptions) {
-		descriptor.Keyword |= keyword
+		options.descriptor.Keyword |= keyword
 	}
 }
 
 // WithTags specifies the tags of the event to be written. Tags is a 28-bit
 // value (top 4 bits are ignored) which are interpreted by the event consumer.
 func WithTags(newTags uint32) EventOpt {
-	return func(descriptor *EventDescriptor, tags *uint32) {
+	return func(options *eventOptions) {
-		*tags |= newTags
+		options.tags |= newTags
+	}
+}
+
+func WithActivityID(activityID *windows.GUID) EventOpt {
+	return func(options *eventOptions) {
+		options.activityID = activityID
+	}
+}
+
+func WithRelatedActivityID(activityID *windows.GUID) EventOpt {
+	return func(options *eventOptions) {
+		options.relatedActivityID = activityID
 	}
 }

internal/etw/provider.go

@@ -181,28 +181,27 @@ func (provider *Provider) IsEnabledForLevelAndKeywords(level Level, keywords uin
 // constructed based on the EventOpt and FieldOpt values that are passed as
 // opts.
 func (provider *Provider) WriteEvent(name string, eventOpts []EventOpt, fieldOpts []FieldOpt) error {
-	tags := uint32(0)
+	options := eventOptions{descriptor: NewEventDescriptor()}
-	descriptor := NewEventDescriptor()
 	em := &EventMetadata{}
 	ed := &EventData{}
 
 	// We need to evaluate the EventOpts first since they might change tags, and
 	// we write out the tags before evaluating FieldOpts.
 	for _, opt := range eventOpts {
-		opt(descriptor, &tags)
+		opt(&options)
 	}
 
-	if !provider.IsEnabledForLevelAndKeywords(descriptor.Level, descriptor.Keyword) {
+	if !provider.IsEnabledForLevelAndKeywords(options.descriptor.Level, options.descriptor.Keyword) {
 		return nil
 	}
 
-	em.WriteEventHeader(name, tags)
+	em.WriteEventHeader(name, options.tags)
 
 	for _, opt := range fieldOpts {
 		opt(em, ed)
 	}
 
-	return provider.WriteEventRaw(descriptor, [][]byte{em.Bytes()}, [][]byte{ed.Bytes()})
+	return provider.WriteEventRaw(options.descriptor, nil, nil, [][]byte{em.Bytes()}, [][]byte{ed.Bytes()})
 }
 
 // WriteEventRaw writes a single ETW event from the provider. This function is
@@ -212,7 +211,13 @@ func (provider *Provider) WriteEvent(name string, eventOpts []EventOpt, fieldOpt
 // schema. The functions on EventMetadata and EventData can help with creating
 // these blobs. The blobs of each type are effectively concatenated together by
 // the ETW infrastructure.
-func (provider *Provider) WriteEventRaw(descriptor *EventDescriptor, metadataBlobs [][]byte, dataBlobs [][]byte) error {
+func (provider *Provider) WriteEventRaw(
+	descriptor *EventDescriptor,
+	activityID *windows.GUID,
+	relatedActivityID *windows.GUID,
+	metadataBlobs [][]byte,
+	dataBlobs [][]byte) error {
+
 	dataDescriptorCount := uint32(1 + len(metadataBlobs) + len(dataBlobs))
 	dataDescriptors := make([]eventDataDescriptor, 0, dataDescriptorCount)
 
@@ -224,5 +229,5 @@ func (provider *Provider) WriteEventRaw(descriptor *EventDescriptor, metadataBlo
 		dataDescriptors = append(dataDescriptors, newEventDataDescriptor(eventDataDescriptorTypeUserData, blob))
 	}
 
-	return eventWriteTransfer(provider.handle, descriptor, nil, nil, dataDescriptorCount, &dataDescriptors[0])
+	return eventWriteTransfer(provider.handle, descriptor, activityID, relatedActivityID, dataDescriptorCount, &dataDescriptors[0])
 }

internal/etw/sample/sample.go

@@ -102,7 +102,7 @@ func main() {
 	ed.WriteString("Item3")
 	ed.WriteString("Item4")
 	ed.WriteString("Item5")
-	if err := provider.WriteEventRaw(descriptor, [][]byte{em.Bytes()}, [][]byte{ed.Bytes()}); err != nil {
+	if err := provider.WriteEventRaw(descriptor, nil, nil, [][]byte{em.Bytes()}, [][]byte{ed.Bytes()}); err != nil {
 		logrus.Error(err)
 		return
 	}