use optics library to manipulate event struct (#37)

bag.go

@@ -8,6 +8,8 @@
 
 package swarm
 
+// TODO: Digest Type combining Digest & Error
+
 // Msg is a generic envelop type for incoming messages.
 // It contains both decoded object and its digest used to acknowledge message.
 type Msg[T any] struct {

event.go

@@ -9,6 +9,8 @@
 package swarm
 
 import (
+	"time"
+
 	"github.com/fogfish/curie"
 	"github.com/fogfish/golem/pure"
 )
@@ -41,6 +43,7 @@ type Event[T any] struct {
 
 	//
 	// Direct performer of the event, a software service that emits action to the stream.
+	// It is automatically defined by the library upon the transmission
 	Agent curie.IRI `json:"agent,omitempty"`
 
 	//
@@ -50,7 +53,11 @@ type Event[T any] struct {
 	//
 	// ISO8601 timestamps when action has been created
 	// It is automatically defined by the library upon the transmission
-	Created string `json:"created,omitempty"`
+	Created time.Time `json:"created,omitempty"`
+
+	//
+	// The object upon which the event is carried out.
+	Object T `json:"object,omitempty"`
 
 	//
 	// The digest of received event (used internally to ack processing)
@@ -59,10 +66,6 @@ type Event[T any] struct {
 	//
 	// The error of event handling (used internally to ack processing)
 	Err error `json:"-"`
-
-	//
-	// The object upon which the event is carried out.
-	Object T `json:"object,omitempty"`
 }
 
 func (Event[T]) HKT1(EventType) {}

go.mod

@@ -12,6 +12,7 @@ require (
 	github.com/aws/constructs-go/constructs/v10 v10.3.0
 	github.com/aws/jsii-runtime-go v1.91.0
 	github.com/fogfish/curie v1.8.2
+	github.com/fogfish/golem/optics v0.11.0
 	github.com/fogfish/golem/pure v0.10.1
 	github.com/fogfish/guid v1.1.0
 	github.com/fogfish/it v1.0.0
@@ -36,6 +37,7 @@ require (
 	github.com/cdklabs/awscdk-asset-kubectl-go/kubectlv20/v2 v2.1.2 // indirect
 	github.com/cdklabs/awscdk-asset-node-proxy-agent-go/nodeproxyagentv6/v2 v2.0.1 // indirect
 	github.com/fatih/color v1.15.0 // indirect
+	github.com/fogfish/golem/hseq v1.1.1 // indirect
 	github.com/mattn/go-colorable v0.1.13 // indirect
 	github.com/mattn/go-isatty v0.0.19 // indirect
 	github.com/yuin/goldmark v1.5.3 // indirect

go.sum

@@ -49,6 +49,10 @@ github.com/fatih/color v1.15.0 h1:kOqh6YHBtK8aywxGerMG2Eq3H6Qgoqeo13Bk2Mv/nBs=
 github.com/fatih/color v1.15.0/go.mod h1:0h5ZqXfHYED7Bhv2ZJamyIOUej9KtShiJESRwBDUSsw=
 github.com/fogfish/curie v1.8.2 h1:+4CezyjZ5uszSXUZAV27gfKwv58w3lKTH0JbQwh3S9A=
 github.com/fogfish/curie v1.8.2/go.mod h1:jPv7pg4hHd8Ug/USG29ZA2bAwlRfh/iinY90/30ATGg=
+github.com/fogfish/golem/hseq v1.1.1 h1:AV8Ziu5wavpvO31NpecxWk56Un7ahGZaUfbcDKtJLV0=
+github.com/fogfish/golem/hseq v1.1.1/go.mod h1:N5y7RLLJyL8iNxFOcD6mkciIBx5TJ9mT1fRszr+ByhQ=
+github.com/fogfish/golem/optics v0.11.0 h1:sIEe6cV/DzpJgobTyWd/GKSXg3XHgNFCsz/huUFqCWc=
+github.com/fogfish/golem/optics v0.11.0/go.mod h1:UO1L+9FWrO6yz1DiqBTEynmM0orI07sw7QBzAGWDtOE=
 github.com/fogfish/golem/pure v0.10.1 h1:0+cnvdaV9zF+0NN8SZMgR5bgFM6yNfBHU4rynYSDfmE=
 github.com/fogfish/golem/pure v0.10.1/go.mod h1:kLPfgu5uKP0CrwVap7jejisRwV7vo1q8Eyqnc/Z0qyw=
 github.com/fogfish/guid v1.1.0 h1:C2dk990rZ+irgUxTISYPlxuyNs323beVo0s4TzdYjzM=

internal/qtest/qtest.go

@@ -142,7 +142,7 @@ func TestEnqueueEvent(t *testing.T, factory enqueue) {
 				Should(it.Equal(*val.Object, Note{Some: "message"})).
 				Should(it.Equal(val.Type, "note:Event[*github.com/fogfish/swarm/internal/qtest.Note]")).
 				ShouldNot(it.Equal(len(val.ID), 0)).
-				ShouldNot(it.Equal(len(val.Created), 0))
+				ShouldNot(it.True(val.Created.IsZero()))
 
 		case <-time.After(50 * time.Millisecond):
 			t.Error("failed to send message")
@@ -236,7 +236,7 @@ func TestDequeueEvent(t *testing.T, factory dequeue) {
 			Type:        "type",
 			Agent:       "agent",
 			Participant: "user",
-			Created:     "created",
+			Created:     time.Date(1970, time.January, 1, 0, 0, 0, 0, time.UTC),
 			Object:      &Note{Some: "message"},
 		}
 		message, _ := json.Marshal(event)
@@ -255,7 +255,7 @@ func TestDequeueEvent(t *testing.T, factory dequeue) {
 			Should(it.Equal(val.Participant, "user")).
 			Should(it.Equal(val.Type, "type")).
 			Should(it.Equal(val.ID, "id")).
-			Should(it.Equal(val.Created, "created")).
+			Should(it.Equal(val.Created, time.Date(1970, time.January, 1, 0, 0, 0, 0, time.UTC))).
 			Should(it.Equal(<-eff, Receipt))
 
 		q.Close()

queue/events/dequeue.go

@@ -11,8 +11,8 @@ package events
 import (
 	"encoding/json"
 	"strings"
-	"unsafe"
 
+	"github.com/fogfish/golem/optics"
 	"github.com/fogfish/swarm"
 	"github.com/fogfish/swarm/internal/pipe"
 )
@@ -29,18 +29,12 @@ func Dequeue[T any, E swarm.EventKind[T]](q swarm.Broker, category ...string) (<
 		cat = category[0]
 	}
 
-	//
-	// building memory layout to make unsafe struct reading
-	kindT := swarm.Event[T]{}
-	offDigest, offFail := unsafe.Offsetof(kindT.Digest),
-		unsafe.Offsetof(kindT.Err)
+	shape := optics.ForShape2[E, string, error]("Digest", "Err")
 
 	sock := q.Dequeue(cat, &ch)
 
 	pipe.ForEach(ch.Ack, func(object *E) {
-		evt := unsafe.Pointer(object)
-		digest := *(*string)(unsafe.Pointer(uintptr(evt) + offDigest))
-		fail := *(*error)(unsafe.Pointer(uintptr(evt) + offFail))
+		digest, fail := shape.Get(object)
 
 		err := conf.Backoff.Retry(func() error {
 			return sock.Ack(swarm.Bag{
@@ -82,8 +76,7 @@ func Dequeue[T any, E swarm.EventKind[T]](q swarm.Broker, category ...string) (<
 			}
 		}
 
-		ptr := unsafe.Pointer(evt)
-		*(*string)(unsafe.Pointer(uintptr(ptr) + offDigest)) = bag.Digest
+		shape.Put(evt, bag.Digest, nil)
 
 		return evt, nil
 	})

queue/events/enqueue.go

@@ -13,16 +13,17 @@ import (
 	"reflect"
 	"strings"
 	"time"
-	"unsafe"
 
+	"github.com/fogfish/curie"
+	"github.com/fogfish/golem/optics"
 	"github.com/fogfish/guid"
 	"github.com/fogfish/swarm"
 	"github.com/fogfish/swarm/internal/pipe"
 )
 
-/*
-Enqueue creates pair of channels to send messages and dead-letter queue
-*/
+// Enqueue creates pair of channels
+// - to send messages
+// - failed messages (dead-letter queue)
 func Enqueue[T any, E swarm.EventKind[T]](q swarm.Broker, category ...string) (chan<- *E, <-chan *E) {
 	conf := q.Config()
 	ch := swarm.NewEvtEnqCh[T, E](conf.EnqueueCapacity)
@@ -32,38 +33,25 @@ func Enqueue[T any, E swarm.EventKind[T]](q swarm.Broker, category ...string) (c
 		cat = category[0]
 	}
 
-	//
-	// building memory layout to make unsafe struct reading
-	kindT := swarm.Event[T]{}
-	offID, offType, offCreated :=
-		unsafe.Offsetof(kindT.ID),
-		unsafe.Offsetof(kindT.Type),
-		unsafe.Offsetof(kindT.Created)
+	shape := optics.ForShape4[E, string, curie.IRI, curie.IRI, time.Time]("ID", "Type", "Agent", "Created")
 
 	sock := q.Enqueue(cat, &ch)
 
 	pipe.ForEach(ch.Msg, func(object *E) {
 		ch.Busy.Lock()
 		defer ch.Busy.Unlock()
 
-		evt := unsafe.Pointer(object)
-
-		// patch ID
-		if len(*(*string)(unsafe.Pointer(uintptr(evt) + offID))) == 0 {
-			id := guid.G.K(guid.Clock).String()
-			*(*string)(unsafe.Pointer(uintptr(evt) + offID)) = id
+		_, knd, src, _ := shape.Get(object)
+		if knd == "" {
+			knd = curie.IRI(cat)
 		}
 
-		// patch Type
-		if len(*(*string)(unsafe.Pointer(uintptr(evt) + offType))) == 0 {
-			*(*string)(unsafe.Pointer(uintptr(evt) + offType)) = cat
+		if src == "" {
+			src = curie.IRI(q.Config().Source)
 		}
 
-		// patch Created
-		if len(*(*string)(unsafe.Pointer(uintptr(evt) + offCreated))) == 0 {
-			t := time.Now().Format(time.RFC3339)
-			*(*string)(unsafe.Pointer(uintptr(evt) + offCreated)) = t
-		}
+		// TODO: migrate to v2
+		shape.Put(object, guid.G.K(guid.Clock).String(), knd, src, time.Now())
 
 		msg, err := json.Marshal(object)
 		if err != nil {