feat: add projection layer to eventstore

Makefile

@@ -2,6 +2,7 @@ export PATH:=$(shell go env GOPATH)/bin:$(PATH)
 export EV_DATA=mem:
 export EV_HTTP=:8080
 export EV_TRACE_SAMPLE=always
+export EV_TRACE_ENDPOINT=localhost:4318
 -include local.mk
 
 air: gen

README.md

@@ -1,3 +1,5 @@
-# ev
+# ev - Eventsourcing Playground
 
-Eventsourcing Playground
+This project is learnings in building an eventstore and applications around it.
+
+Feel free to explore.

app/gql/resolver.go

@@ -14,7 +14,7 @@ import (
 	"github.com/sour-is/ev/app/msgbus"
 	"github.com/sour-is/ev/app/salty"
 	"github.com/sour-is/ev/internal/graph/generated"
-	"github.com/sour-is/ev/internal/logz"
+	"github.com/sour-is/ev/internal/lg"
 	"github.com/sour-is/ev/pkg/es"
 	"github.com/sour-is/ev/pkg/gql"
 	"github.com/vektah/gqlparser/v2/gqlerror"
@@ -27,7 +27,7 @@ type Resolver struct {
 }
 
 func New(ctx context.Context, resolvers ...interface{ RegisterHTTP(*http.ServeMux) }) (*Resolver, error) {
-	_, span := logz.Span(ctx)
+	_, span := lg.Span(ctx)
 	defer span.End()
 
 	r := &Resolver{}
@@ -90,7 +90,7 @@ func (r *Resolver) RegisterHTTP(mux *http.ServeMux) {
 	gql.SetRecoverFunc(NoopRecover)
 	gql.Use(otelgqlgen.Middleware())
 	mux.Handle("/", playground.Handler("GraphQL playground", "/gql"))
-	mux.Handle("/gql", logz.Htrace(r.ChainMiddlewares(gql), "gql"))
+	mux.Handle("/gql", lg.Htrace(r.ChainMiddlewares(gql), "gql"))
 }
 
 type noop struct{}

app/msgbus/service.go

@@ -12,7 +12,7 @@ import (
 	"time"
 
 	"github.com/gorilla/websocket"
-	"github.com/sour-is/ev/internal/logz"
+	"github.com/sour-is/ev/internal/lg"
 	"github.com/sour-is/ev/pkg/es"
 	"github.com/sour-is/ev/pkg/es/event"
 	"github.com/sour-is/ev/pkg/gql"
@@ -35,7 +35,7 @@ type MsgbusResolver interface {
 }
 
 func New(ctx context.Context, es *es.EventStore) (*service, error) {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	if err := event.Register(ctx, &PostEvent{}); err != nil {
@@ -45,7 +45,7 @@ func New(ctx context.Context, es *es.EventStore) (*service, error) {
 		return nil, err
 	}
 
-	m := logz.Meter(ctx)
+	m := lg.Meter(ctx)
 
 	svc := &service{es: es}
 
@@ -72,11 +72,11 @@ var upgrader = websocket.Upgrader{
 }
 
 func (s *service) RegisterHTTP(mux *http.ServeMux) {
-	mux.Handle("/inbox/", logz.Htrace(http.StripPrefix("/inbox/", s), "inbox"))
+	mux.Handle("/inbox/", lg.Htrace(http.StripPrefix("/inbox/", s), "inbox"))
 }
 func (s *service) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	ctx := r.Context()
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 	r = r.WithContext(ctx)
 
@@ -97,7 +97,7 @@ func (s *service) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 
 // Posts is the resolver for the events field.
 func (r *service) Posts(ctx context.Context, streamID string, paging *gql.PageInput) (*gql.Connection, error) {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	r.Mresolver_posts.Add(ctx, 1)
@@ -143,7 +143,7 @@ func (r *service) Posts(ctx context.Context, streamID string, paging *gql.PageIn
 }
 
 func (r *service) PostAdded(ctx context.Context, streamID string, after int64) (<-chan *PostEvent, error) {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	r.Mresolver_post_added.Add(ctx, 1)
@@ -162,15 +162,19 @@ func (r *service) PostAdded(ctx context.Context, streamID string, after int64) (
 	ch := make(chan *PostEvent)
 
 	go func() {
-		ctx, span := logz.Span(ctx)
+		ctx, span := lg.Span(ctx)
 		defer span.End()
 
-		defer func() {
+		{
-			ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
+			ctx, span := lg.Fork(ctx)
-			defer cancel()
+			defer func() {
-			err := sub.Close(ctx)
+				defer span.End()
-			span.RecordError(err)
+				ctx, cancel := context.WithTimeout(ctx, 1*time.Second)
-		}()
+				defer cancel()
+				err := sub.Close(ctx)
+				span.RecordError(err)
+			}()
+		}
 
 		for sub.Recv(ctx) {
 			events, err := sub.Events(ctx)
@@ -199,7 +203,7 @@ func (r *service) PostAdded(ctx context.Context, streamID string, after int64) (
 
 func (s *service) get(w http.ResponseWriter, r *http.Request) {
 	ctx := r.Context()
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	name, _, _ := strings.Cut(r.URL.Path, "/")
@@ -253,7 +257,7 @@ func (s *service) get(w http.ResponseWriter, r *http.Request) {
 func (s *service) post(w http.ResponseWriter, r *http.Request) {
 	ctx := r.Context()
 
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	name, tags, _ := strings.Cut(r.URL.Path, "/")
@@ -320,7 +324,7 @@ func (s *service) post(w http.ResponseWriter, r *http.Request) {
 }
 func (s *service) websocket(w http.ResponseWriter, r *http.Request) {
 	ctx := r.Context()
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	name, _, _ := strings.Cut(r.URL.Path, "/")
@@ -381,12 +385,16 @@ func (s *service) websocket(w http.ResponseWriter, r *http.Request) {
 		span.RecordError(err)
 		return
 	}
-	defer func() {
+	{
-		ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
+		ctx, span := lg.Fork(ctx)
-		defer cancel()
+		defer func() {
-		span.AddEvent("stop ws")
+			defer span.End()
-		sub.Close(ctx)
+			ctx, cancel := context.WithTimeout(ctx, 1*time.Second)
-	}()
+			defer cancel()
+			err := sub.Close(ctx)
+			span.RecordError(err)
+		}()
+	}
 
 	span.AddEvent("start ws")
 	for sub.Recv(ctx) {

app/peerfinder/service.go

@@ -11,7 +11,7 @@ import (
 	ulid "github.com/oklog/ulid/v2"
 	contentnegotiation "gitlab.com/jamietanna/content-negotiation-go"
 
-	"github.com/sour-is/ev/internal/logz"
+	"github.com/sour-is/ev/internal/lg"
 	"github.com/sour-is/ev/pkg/es"
 	"github.com/sour-is/ev/pkg/es/event"
 )
@@ -28,7 +28,7 @@ type service struct {
 }
 
 func New(ctx context.Context, es *es.EventStore) (*service, error) {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	if err := event.Register(ctx, &Request{}, &Result{}, &VersionChanged{}); err != nil {
@@ -41,13 +41,13 @@ func New(ctx context.Context, es *es.EventStore) (*service, error) {
 	return svc, nil
 }
 func (s *service) RegisterHTTP(mux *http.ServeMux) {
-	mux.Handle("/peers/", logz.Htrace(s, "peers"))
+	mux.Handle("/peers/", lg.Htrace(s, "peers"))
 
 }
 func (s *service) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	ctx := r.Context()
 
-	_, span := logz.Span(ctx)
+	_, span := lg.Span(ctx)
 	defer span.End()
 
 	r = r.WithContext(ctx)
@@ -90,7 +90,7 @@ func (s *service) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 func (s *service) getPending(w http.ResponseWriter, r *http.Request, uuid string) {
 	ctx := r.Context()
 
-	_, span := logz.Span(ctx)
+	_, span := lg.Span(ctx)
 	defer span.End()
 
 	info, err := es.Upsert(ctx, s.es, "pf-info", func(ctx context.Context, agg *Info) error {

app/salty/salty-addr.go

@@ -10,7 +10,7 @@ import (
 	"strings"
 
 	"github.com/keys-pub/keys"
-	"github.com/sour-is/ev/internal/logz"
+	"github.com/sour-is/ev/internal/lg"
 )
 
 // Config represents a Salty Config for a User which at a minimum is required
@@ -79,7 +79,7 @@ func (a *Addr) DiscoveredDomain() string {
 }
 
 func (a *Addr) Refresh(ctx context.Context) error {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	span.AddEvent(fmt.Sprintf("Looking up SRV record for _salty._tcp.%s", a.Domain))
@@ -118,7 +118,7 @@ func (a *Addr) Refresh(ctx context.Context) error {
 }
 
 func fetchConfig(ctx context.Context, addr string) (config Config, cap Capabilities, err error) {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	var req *http.Request

app/salty/service.go

@@ -12,7 +12,7 @@ import (
 	"strings"
 
 	"github.com/keys-pub/keys"
-	"github.com/sour-is/ev/internal/logz"
+	"github.com/sour-is/ev/internal/lg"
 	"github.com/sour-is/ev/pkg/es"
 	"github.com/sour-is/ev/pkg/es/event"
 	"github.com/sour-is/ev/pkg/gql"
@@ -49,7 +49,7 @@ type SaltyResolver interface {
 }
 
 func New(ctx context.Context, es *es.EventStore, baseURL string) (*service, error) {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	if err := event.Register(ctx, &UserRegistered{}); err != nil {
@@ -59,7 +59,7 @@ func New(ctx context.Context, es *es.EventStore, baseURL string) (*service, erro
 		return nil, err
 	}
 
-	m := logz.Meter(ctx)
+	m := lg.Meter(ctx)
 
 	svc := &service{baseURL: baseURL, es: es, dns: net.DefaultResolver}
 
@@ -93,7 +93,7 @@ func (s *service) BaseURL() string {
 	return s.baseURL
 }
 func (s *service) RegisterHTTP(mux *http.ServeMux) {
-	mux.Handle("/.well-known/salty/", logz.Htrace(s, "lookup"))
+	mux.Handle("/.well-known/salty/", lg.Htrace(s, "lookup"))
 }
 func (s *service) RegisterAPIv1(mux *http.ServeMux) {
 	mux.HandleFunc("/ping", s.apiv1)
@@ -103,7 +103,7 @@ func (s *service) RegisterAPIv1(mux *http.ServeMux) {
 }
 func (s *service) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	ctx := r.Context()
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	addr := "saltyuser-" + strings.TrimPrefix(r.URL.Path, "/.well-known/salty/")
@@ -137,7 +137,7 @@ func (s *service) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	}
 }
 func (s *service) CreateSaltyUser(ctx context.Context, nick string, pub string) (*SaltyUser, error) {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	s.m_create_user.Add(ctx, 1)
@@ -167,7 +167,7 @@ func (s *service) CreateSaltyUser(ctx context.Context, nick string, pub string)
 	return a, nil
 }
 func (s *service) SaltyUser(ctx context.Context, nick string) (*SaltyUser, error) {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	s.m_get_user.Add(ctx, 1)
@@ -200,7 +200,7 @@ func (s *service) GetMiddleware() func(http.Handler) http.Handler {
 func (s *service) apiv1(w http.ResponseWriter, r *http.Request) {
 	ctx := r.Context()
 
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	switch r.Method {

env

@@ -1,5 +0,0 @@
-SCRIPT_VERSION=1.1.0
-REQ_ID=01GB0GDHCEAPMZFVES2KBCN7KF
-REQ_IP=1.1.1.1
-REQ_FAMILY=1
-REQ_CREATED=2022-08-21 09:30:22

httpmux.go

@@ -0,0 +1,37 @@
+package main
+
+import (
+	"net/http"
+
+	"github.com/rs/cors"
+)
+
+type mux struct {
+	*http.ServeMux
+	api *http.ServeMux
+}
+
+func httpMux(fns ...interface{ RegisterHTTP(*http.ServeMux) }) http.Handler {
+	mux := newMux()
+	for _, fn := range fns {
+		fn.RegisterHTTP(mux.ServeMux)
+
+		if fn, ok := fn.(interface{ RegisterAPIv1(*http.ServeMux) }); ok {
+			fn.RegisterAPIv1(mux.api)
+		}
+	}
+
+	return cors.AllowAll().Handler(mux)
+}
+func newMux() *mux {
+	mux := &mux{
+		api:      http.NewServeMux(),
+		ServeMux: http.NewServeMux(),
+	}
+	mux.Handle("/api/v1/", http.StripPrefix("/api/v1/", mux.api))
+
+	return mux
+}
+func (m mux) HandleAPIv1(pattern string, handler http.Handler) {
+	m.api.Handle(pattern, handler)
+}

internal/lg/init.go

@@ -1,4 +1,4 @@
-package logz
+package lg
 
 import (
 	"context"

internal/lg/logger.go

@@ -1,4 +1,4 @@
-package logz
+package lg
 
 import (
 	"bytes"
@@ -72,7 +72,7 @@ func initLogger(name string) func() error {
 	l, err := logzio.New(
 		token.Secret(),
 		// logzio.SetDebug(os.Stderr),
-		logzio.SetUrl(env("LOGZIO_LOG_URL", "https://listener.logz.io:8071")),
+		logzio.SetUrl(env("LOGZIO_LOG_URL", "https://listener.lg.io:8071")),
 		logzio.SetDrainDuration(time.Second*5),
 		logzio.SetTempDirectory(env("LOGZIO_DIR", os.TempDir())),
 		logzio.SetCheckDiskSpace(true),

internal/lg/metric.go

@@ -1,4 +1,4 @@
-package logz
+package lg
 
 import (
 	"context"

internal/lg/tracer.go

@@ -1,4 +1,4 @@
-package logz
+package lg
 
 import (
 	"context"
@@ -33,10 +33,10 @@ func Tracer(ctx context.Context) trace.Tracer {
 	return otel.Tracer("")
 }
 
-func Span(ctx context.Context, opts ...trace.SpanStartOption) (context.Context, trace.Span) {
+func attrs(ctx context.Context) (string, []attribute.KeyValue) {
 	var attrs []attribute.KeyValue
 	var name string
-	if pc, file, line, ok := runtime.Caller(1); ok {
+	if pc, file, line, ok := runtime.Caller(2); ok {
 		if fn := runtime.FuncForPC(pc); fn != nil {
 			name = fn.Name()
 		}
@@ -47,12 +47,29 @@ func Span(ctx context.Context, opts ...trace.SpanStartOption) (context.Context,
 			attribute.String("name", name),
 		)
 	}
+	return name, attrs
+}
+
+func Span(ctx context.Context, opts ...trace.SpanStartOption) (context.Context, trace.Span) {
+	name, attrs := attrs(ctx)
 	ctx, span := Tracer(ctx).Start(ctx, name, opts...)
 	span.SetAttributes(attrs...)
 
 	return ctx, span
 }
 
+func Fork(ctx context.Context, opts ...trace.SpanStartOption) (context.Context, trace.Span) {
+	name, attrs := attrs(ctx)
+	childCTX, childSpan := Tracer(ctx).Start(context.Background(), name, append(opts, trace.WithLinks(trace.LinkFromContext(ctx)))...)
+	childSpan.SetAttributes(attrs...)
+
+	_, span := Tracer(ctx).Start(ctx, name, append(opts, trace.WithLinks(trace.LinkFromContext(childCTX)))...)
+	span.SetAttributes(attrs...)
+	defer span.End()
+
+	return childCTX, childSpan
+}
+
 type SampleRate string
 
 const (

main.go

@@ -1,9 +1,7 @@
 package main
 
 import (
-	"bytes"
 	"context"
-	"fmt"
 	"log"
 	"net/http"
 	"os"
@@ -12,18 +10,21 @@ import (
 	"strings"
 	"time"
 
-	"github.com/rs/cors"
+	"go.uber.org/multierr"
 	"golang.org/x/sync/errgroup"
 
 	"github.com/sour-is/ev/app/gql"
 	"github.com/sour-is/ev/app/msgbus"
 	"github.com/sour-is/ev/app/peerfinder"
 	"github.com/sour-is/ev/app/salty"
-	"github.com/sour-is/ev/internal/logz"
+	"github.com/sour-is/ev/internal/lg"
 	"github.com/sour-is/ev/pkg/es"
 	diskstore "github.com/sour-is/ev/pkg/es/driver/disk-store"
 	memstore "github.com/sour-is/ev/pkg/es/driver/mem-store"
+	"github.com/sour-is/ev/pkg/es/driver/projecter"
 	"github.com/sour-is/ev/pkg/es/driver/streamer"
+	"github.com/sour-is/ev/pkg/es/event"
+	"github.com/sour-is/ev/pkg/set"
 )
 
 const AppName string = "sour.is-ev"
@@ -35,7 +36,7 @@ func main() {
 		defer cancel()
 	}()
 
-	ctx, stop := logz.Init(ctx, AppName)
+	ctx, stop := lg.Init(ctx, AppName)
 	defer stop()
 
 	if err := run(ctx); err != nil && err != http.ErrServerClosed {
@@ -46,12 +47,20 @@ func run(ctx context.Context) error {
 	g, ctx := errgroup.WithContext(ctx)
 
 	{
-		ctx, span := logz.Span(ctx)
+		ctx, span := lg.Span(ctx)
 
-		diskstore.Init(ctx)
+		err := multierr.Combine(
-		memstore.Init(ctx)
+			es.Init(ctx),
+			event.Init(ctx),
+			diskstore.Init(ctx),
+			memstore.Init(ctx),
+		)
+		if err != nil {
+			span.RecordError(err)
+			return err
+		}
 
-		es, err := es.Open(ctx, env("EV_DATA", "file:data"), streamer.New(ctx))
+		es, err := es.Open(ctx, env("EV_DATA", "mem:"), streamer.New(ctx), projecter.New(ctx))
 		if err != nil {
 			span.RecordError(err)
 			return err
@@ -65,7 +74,7 @@ func run(ctx context.Context) error {
 			s.Addr = "[::]" + s.Addr
 		}
 
-		enable := set(strings.Fields(env("EV_ENABLE", "salty msgbus gql peers"))...)
+		enable := set.New(strings.Fields(env("EV_ENABLE", "salty msgbus gql peers"))...)
 		var svcs []interface{ RegisterHTTP(*http.ServeMux) }
 
 		svcs = append(svcs, es)
@@ -109,14 +118,14 @@ func run(ctx context.Context) error {
 			}
 			svcs = append(svcs, gql)
 		}
-		svcs = append(svcs, logz.NewHTTP(ctx))
+		svcs = append(svcs, lg.NewHTTP(ctx))
 
 		s.Handler = httpMux(svcs...)
 
 		log.Print("Listen on ", s.Addr)
-		span.AddEvent("begin listen and serve")
+		span.AddEvent("begin listen and serve on " + s.Addr)
 
-		Mup, err := logz.Meter(ctx).SyncInt64().UpDownCounter("up")
+		Mup, err := lg.Meter(ctx).SyncInt64().UpDownCounter("up")
 		if err != nil {
 			return err
 		}
@@ -149,61 +158,3 @@ func env(name, defaultValue string) string {
 	log.Println("#", name, "=", defaultValue, "(default)")
 	return defaultValue
 }
-func httpMux(fns ...interface{ RegisterHTTP(*http.ServeMux) }) http.Handler {
-	mux := newMux()
-	for _, fn := range fns {
-		fn.RegisterHTTP(mux.ServeMux)
-
-		if fn, ok := fn.(interface{ RegisterAPIv1(*http.ServeMux) }); ok {
-			fn.RegisterAPIv1(mux.api)
-		}
-	}
-
-	return cors.AllowAll().Handler(mux)
-}
-
-type Set[T comparable] map[T]struct{}
-
-func set[T comparable](items ...T) Set[T] {
-	s := make(map[T]struct{}, len(items))
-	for i := range items {
-		s[items[i]] = struct{}{}
-	}
-	return s
-}
-func (s Set[T]) Has(v T) bool {
-	_, ok := (s)[v]
-	return ok
-}
-func (s Set[T]) String() string {
-	if s == nil {
-		return "set(<nil>)"
-	}
-	lis := make([]string, 0, len(s))
-	for k := range s {
-		lis = append(lis, fmt.Sprint(k))
-	}
-
-	var b bytes.Buffer
-	b.WriteString("set(")
-	b.WriteString(strings.Join(lis, ","))
-	b.WriteString(")")
-	return b.String()
-}
-
-type mux struct {
-	*http.ServeMux
-	api *http.ServeMux
-}
-func newMux() *mux {
-	mux := &mux{
-		api: http.NewServeMux(),
-		ServeMux: http.NewServeMux(),
-	}
-	mux.Handle("/api/v1/", http.StripPrefix("/api/v1/", mux.api))
-
-	return mux
-}
-func (m mux) HandleAPIv1(pattern string, handler http.Handler) {
-	m.api.Handle(pattern, handler)
-}

pkg/es/driver/disk-store/disk-store.go

@@ -11,7 +11,7 @@ import (
 	"go.opentelemetry.io/otel/metric/instrument/syncint64"
 	"go.uber.org/multierr"
 
-	"github.com/sour-is/ev/internal/logz"
+	"github.com/sour-is/ev/internal/lg"
 	"github.com/sour-is/ev/pkg/cache"
 	"github.com/sour-is/ev/pkg/es"
 	"github.com/sour-is/ev/pkg/es/driver"
@@ -38,10 +38,10 @@ const AppendOnly = es.AppendOnly
 const AllEvents = es.AllEvents
 
 func Init(ctx context.Context) error {
-	_, span := logz.Span(ctx)
+	_, span := lg.Span(ctx)
 	defer span.End()
 
-	m := logz.Meter(ctx)
+	m := lg.Meter(ctx)
 	var err, errs error
 
 	Mdisk_open, err := m.SyncInt64().Counter("disk_open")
@@ -61,7 +61,7 @@ func Init(ctx context.Context) error {
 var _ driver.Driver = (*diskStore)(nil)
 
 func (d *diskStore) Open(ctx context.Context, dsn string) (driver.Driver, error) {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	d.Mdisk_open.Add(ctx, 1)
@@ -82,11 +82,11 @@ func (d *diskStore) Open(ctx context.Context, dsn string) (driver.Driver, error)
 		}
 	}
 	c, err := cache.NewWithEvict(CachSize, func(ctx context.Context, s string, l *lockedWal) {
-		_, span := logz.Span(ctx)
+		_, span := lg.Span(ctx)
 		defer span.End()
 
 		l.Modify(ctx, func(w *wal.Log) error {
-			_, span := logz.Span(ctx)
+			_, span := lg.Span(ctx)
 			defer span.End()
 
 			d.Mdisk_evict.Add(ctx, 1)
@@ -112,13 +112,13 @@ func (d *diskStore) Open(ctx context.Context, dsn string) (driver.Driver, error)
 	}, nil
 }
 func (d *diskStore) EventLog(ctx context.Context, streamID string) (driver.EventLog, error) {
-	_, span := logz.Span(ctx)
+	_, span := lg.Span(ctx)
 	defer span.End()
 
 	el := &eventLog{streamID: streamID}
 
 	return el, d.openlogs.Modify(ctx, func(openlogs *openlogs) error {
-		_, span := logz.Span(ctx)
+		_, span := lg.Span(ctx)
 		defer span.End()
 
 		if events, ok := openlogs.logs.Get(streamID); ok {
@@ -145,14 +145,14 @@ type eventLog struct {
 var _ driver.EventLog = (*eventLog)(nil)
 
 func (e *eventLog) Append(ctx context.Context, events event.Events, version uint64) (uint64, error) {
-	_, span := logz.Span(ctx)
+	_, span := lg.Span(ctx)
 	defer span.End()
 
 	event.SetStreamID(e.streamID, events...)
 
 	var count uint64
 	err := e.events.Modify(ctx, func(l *wal.Log) error {
-		_, span := logz.Span(ctx)
+		_, span := lg.Span(ctx)
 		defer span.End()
 
 		last, err := l.LastIndex()
@@ -190,13 +190,13 @@ func (e *eventLog) Append(ctx context.Context, events event.Events, version uint
 	return count, err
 }
 func (e *eventLog) Read(ctx context.Context, pos, count int64) (event.Events, error) {
-	_, span := logz.Span(ctx)
+	_, span := lg.Span(ctx)
 	defer span.End()
 
 	var events event.Events
 
 	err := e.events.Modify(ctx, func(stream *wal.Log) error {
-		_, span := logz.Span(ctx)
+		_, span := lg.Span(ctx)
 		defer span.End()
 
 		first, err := stream.FirstIndex()
@@ -259,7 +259,7 @@ func (e *eventLog) Read(ctx context.Context, pos, count int64) (event.Events, er
 	return events, nil
 }
 func (e *eventLog) FirstIndex(ctx context.Context) (uint64, error) {
-	_, span := logz.Span(ctx)
+	_, span := lg.Span(ctx)
 	defer span.End()
 
 	var idx uint64
@@ -273,7 +273,7 @@ func (e *eventLog) FirstIndex(ctx context.Context) (uint64, error) {
 	return idx, err
 }
 func (e *eventLog) LastIndex(ctx context.Context) (uint64, error) {
-	_, span := logz.Span(ctx)
+	_, span := lg.Span(ctx)
 	defer span.End()
 
 	var idx uint64

pkg/es/driver/mem-store/mem-store.go

@@ -4,7 +4,7 @@ import (
 	"context"
 	"fmt"
 
-	"github.com/sour-is/ev/internal/logz"
+	"github.com/sour-is/ev/internal/lg"
 	"github.com/sour-is/ev/pkg/es"
 	"github.com/sour-is/ev/pkg/es/driver"
 	"github.com/sour-is/ev/pkg/es/event"
@@ -26,30 +26,30 @@ type memstore struct {
 const AppendOnly = es.AppendOnly
 const AllEvents = es.AllEvents
 
-func Init(ctx context.Context) {
+func Init(ctx context.Context) error {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
-	es.Register(ctx, "mem", &memstore{})
+	return es.Register(ctx, "mem", &memstore{})
 }
 
 var _ driver.Driver = (*memstore)(nil)
 
 func (memstore) Open(ctx context.Context, name string) (driver.Driver, error) {
-	_, span := logz.Span(ctx)
+	_, span := lg.Span(ctx)
 	defer span.End()
 
 	s := &state{streams: make(map[string]*locker.Locked[event.Events])}
 	return &memstore{locker.New(s)}, nil
 }
 func (m *memstore) EventLog(ctx context.Context, streamID string) (driver.EventLog, error) {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	el := &eventLog{streamID: streamID}
 
 	err := m.state.Modify(ctx, func(state *state) error {
-		_, span := logz.Span(ctx)
+		_, span := lg.Span(ctx)
 		defer span.End()
 
 		l, ok := state.streams[streamID]
@@ -70,16 +70,16 @@ var _ driver.EventLog = (*eventLog)(nil)
 
 // Append implements driver.EventStore
 func (m *eventLog) Append(ctx context.Context, events event.Events, version uint64) (uint64, error) {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	event.SetStreamID(m.streamID, events...)
 
 	return uint64(len(events)), m.events.Modify(ctx, func(stream *event.Events) error {
-		_, span := logz.Span(ctx)
+		_, span := lg.Span(ctx)
 		defer span.End()
 
-		span.AddEvent(fmt.Sprintf(" %s %#v %d", m.streamID, stream, len(*stream)))
+		span.AddEvent(fmt.Sprintf(" %s %d", m.streamID, len(*stream)))
 
 		last := uint64(len(*stream))
 		if version != AppendOnly && version != last {
@@ -100,16 +100,16 @@ func (m *eventLog) Append(ctx context.Context, events event.Events, version uint
 
 // Read implements driver.EventStore
 func (m *eventLog) Read(ctx context.Context, pos int64, count int64) (event.Events, error) {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	var events event.Events
 
 	err := m.events.Modify(ctx, func(stream *event.Events) error {
-		_, span := logz.Span(ctx)
+		_, span := lg.Span(ctx)
 		defer span.End()
 
-		span.AddEvent(fmt.Sprintf(" %s %#v %d", m.streamID, stream, len(*stream)))
+		span.AddEvent(fmt.Sprintf("%s %d", m.streamID, len(*stream)))
 
 		first := stream.First().EventMeta().Position
 		last := stream.Last().EventMeta().Position
@@ -154,7 +154,7 @@ func (m *eventLog) Read(ctx context.Context, pos int64, count int64) (event.Even
 
 // FirstIndex for the streamID
 func (m *eventLog) FirstIndex(ctx context.Context) (uint64, error) {
-	_, span := logz.Span(ctx)
+	_, span := lg.Span(ctx)
 	defer span.End()
 
 	events, err := m.events.Copy(ctx)
@@ -163,7 +163,7 @@ func (m *eventLog) FirstIndex(ctx context.Context) (uint64, error) {
 
 // LastIndex for the streamID
 func (m *eventLog) LastIndex(ctx context.Context) (uint64, error) {
-	_, span := logz.Span(ctx)
+	_, span := lg.Span(ctx)
 	defer span.End()
 
 	events, err := m.events.Copy(ctx)

pkg/es/driver/projecter/projecter.go

@@ -0,0 +1,127 @@
+package projecter
+
+import (
+	"context"
+	"strings"
+
+	"github.com/sour-is/ev/internal/lg"
+	"github.com/sour-is/ev/pkg/es"
+	"github.com/sour-is/ev/pkg/es/driver"
+	"github.com/sour-is/ev/pkg/es/event"
+)
+
+type projector struct {
+	up driver.Driver
+}
+
+func New(ctx context.Context) *projector {
+	return &projector{}
+}
+func (p *projector) Apply(e *es.EventStore) {
+	p.up = e.Driver
+	e.Driver = p
+}
+func (s *projector) Unwrap() driver.Driver {
+	return s.up
+}
+func (s *projector) Open(ctx context.Context, dsn string) (driver.Driver, error) {
+	ctx, span := lg.Span(ctx)
+	defer span.End()
+
+	return s.up.Open(ctx, dsn)
+}
+func (s *projector) EventLog(ctx context.Context, streamID string) (driver.EventLog, error) {
+	ctx, span := lg.Span(ctx)
+	defer span.End()
+
+	l, err := s.up.EventLog(ctx, streamID)
+	return &wrapper{l, s}, err
+}
+
+type wrapper struct {
+	up        driver.EventLog
+	projector *projector
+}
+
+var _ driver.EventLog = (*wrapper)(nil)
+
+func (w *wrapper) Read(ctx context.Context, pos int64, count int64) (event.Events, error) {
+	ctx, span := lg.Span(ctx)
+	defer span.End()
+
+	return w.up.Read(ctx, pos, count)
+}
+func (w *wrapper) Append(ctx context.Context, events event.Events, version uint64) (uint64, error) {
+	ctx, span := lg.Span(ctx)
+	defer span.End()
+
+	i, err := w.up.Append(ctx, events, version)
+	if err != nil {
+		return i, err
+	}
+
+	{
+		ctx, span := lg.Fork(ctx)
+
+		go func() {
+			defer span.End()
+
+			var pevents []event.Event
+
+			for i := range events {
+				e := events[i]
+				eventType := event.TypeOf(e)
+				streamID := e.EventMeta().StreamID
+				streamPos := e.EventMeta().Position
+
+				e1 := event.NewPtr(streamID, streamPos)
+				event.SetStreamID("$all", e1)
+
+				e2 := event.NewPtr(streamID, streamPos)
+				event.SetStreamID("$type-"+eventType, e2)
+
+				e3 := event.NewPtr(streamID, streamPos)
+				pkg, _, _ := strings.Cut(eventType, ".")
+				event.SetStreamID("$pkg-"+pkg, e3)
+
+				pevents = append(
+					pevents,
+					e1,
+					e2,
+					e3,
+				)
+			}
+
+			for i := range pevents {
+				e := pevents[i]
+				l, err := w.projector.up.EventLog(ctx, event.StreamID(e).StreamID())
+				if err != nil {
+					span.RecordError(err)
+					continue
+				}
+				_, err = l.Append(ctx, event.NewEvents(e), es.AppendOnly)
+				span.RecordError(err)
+			}
+		}()
+	}
+
+	return i, err
+}
+func (w *wrapper) FirstIndex(ctx context.Context) (uint64, error) {
+	ctx, span := lg.Span(ctx)
+	defer span.End()
+
+	return w.up.FirstIndex(ctx)
+}
+func (w *wrapper) LastIndex(ctx context.Context) (uint64, error) {
+	ctx, span := lg.Span(ctx)
+	defer span.End()
+
+	return w.up.LastIndex(ctx)
+}
+func (w *wrapper) LoadForUpdate(ctx context.Context, a event.Aggregate, fn func(context.Context, event.Aggregate) error) (uint64, error) {
+	ctx, span := lg.Span(ctx)
+	defer span.End()
+
+	return w.up.LoadForUpdate(ctx, a, fn)
+}

pkg/es/driver/streamer/streamer.go

@@ -2,12 +2,15 @@ package streamer
 
 import (
 	"context"
+	"fmt"
 
-	"github.com/sour-is/ev/internal/logz"
+	"github.com/sour-is/ev/internal/lg"
 	"github.com/sour-is/ev/pkg/es"
 	"github.com/sour-is/ev/pkg/es/driver"
 	"github.com/sour-is/ev/pkg/es/event"
 	"github.com/sour-is/ev/pkg/locker"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/trace"
 )
 
 type state struct {
@@ -20,7 +23,7 @@ type streamer struct {
 }
 
 func New(ctx context.Context) *streamer {
-	ctx, span := logz.Span(ctx)
+	_, span := lg.Span(ctx)
 	defer span.End()
 
 	return &streamer{state: locker.New(&state{subscribers: map[string][]*subscription{}})}
@@ -39,13 +42,13 @@ func (s *streamer) Unwrap() driver.Driver {
 var _ driver.Driver = (*streamer)(nil)
 
 func (s *streamer) Open(ctx context.Context, dsn string) (driver.Driver, error) {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	return s.up.Open(ctx, dsn)
 }
 func (s *streamer) EventLog(ctx context.Context, streamID string) (driver.EventLog, error) {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	l, err := s.up.EventLog(ctx, streamID)
@@ -55,7 +58,7 @@ func (s *streamer) EventLog(ctx context.Context, streamID string) (driver.EventL
 var _ driver.EventStream = (*streamer)(nil)
 
 func (s *streamer) Subscribe(ctx context.Context, streamID string, start int64) (driver.Subscription, error) {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	events, err := s.up.EventLog(ctx, streamID)
@@ -75,22 +78,24 @@ func (s *streamer) Subscribe(ctx context.Context, streamID string, start int64)
 	})
 }
 func (s *streamer) Send(ctx context.Context, streamID string, events event.Events) error {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	return s.state.Modify(ctx, func(state *state) error {
-		ctx, span := logz.Span(ctx)
+		ctx, span := lg.Span(ctx)
 		defer span.End()
+		span.AddEvent(fmt.Sprint("subscribers=", len(state.subscribers[streamID])))
 
 		for _, sub := range state.subscribers[streamID] {
 			err := sub.position.Modify(ctx, func(position *position) error {
-				_, span := logz.Span(ctx)
+				_, span := lg.Span(ctx)
 				defer span.End()
 
 				position.size = int64(events.Last().EventMeta().Position - uint64(position.idx))
 
 				if position.wait != nil {
 					close(position.wait)
+					position.link = trace.LinkFromContext(ctx, attribute.String("src", "event"))
 					position.wait = nil
 				}
 				return nil
@@ -102,17 +107,16 @@ func (s *streamer) Send(ctx context.Context, streamID string, events event.Event
 		return nil
 	})
 }
-
 func (s *streamer) delete(streamID string, sub *subscription) func(context.Context) error {
 	return func(ctx context.Context) error {
-		ctx, span := logz.Span(ctx)
+		ctx, span := lg.Span(ctx)
 		defer span.End()
 
 		if err := ctx.Err(); err != nil {
 			return err
 		}
 		return s.state.Modify(ctx, func(state *state) error {
-			_, span := logz.Span(ctx)
+			_, span := lg.Span(ctx)
 			defer span.End()
 
 			lis := state.subscribers[streamID]
@@ -138,44 +142,53 @@ type wrapper struct {
 var _ driver.EventLog = (*wrapper)(nil)
 
 func (w *wrapper) Read(ctx context.Context, pos int64, count int64) (event.Events, error) {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	return w.up.Read(ctx, pos, count)
 }
-
 func (w *wrapper) Append(ctx context.Context, events event.Events, version uint64) (uint64, error) {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	i, err := w.up.Append(ctx, events, version)
 	if err != nil {
 		return i, err
 	}
-	return i, w.streamer.Send(ctx, w.topic, events)
-}
 
+	ctx, span = lg.Fork(ctx)
+	go func() {
+		defer span.End()
+
+		err := w.streamer.Send(ctx, w.topic, events)
+		span.RecordError(err)
+	}()
+
+	return i, nil
+}
 func (w *wrapper) FirstIndex(ctx context.Context) (uint64, error) {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	return w.up.FirstIndex(ctx)
 }
-
 func (w *wrapper) LastIndex(ctx context.Context) (uint64, error) {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	return w.up.LastIndex(ctx)
 }
-
 func (w *wrapper) LoadForUpdate(ctx context.Context, a event.Aggregate, fn func(context.Context, event.Aggregate) error) (uint64, error) {
+	ctx, span := lg.Span(ctx)
+	defer span.End()
+
 	return w.up.LoadForUpdate(ctx, a, fn)
 }
 
 type position struct {
 	size int64
 	idx  int64
+	link trace.Link
 	wait chan struct{}
 }
 
@@ -189,13 +202,13 @@ type subscription struct {
 }
 
 func (s *subscription) Recv(ctx context.Context) bool {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	var wait func(context.Context) bool
 
 	err := s.position.Modify(ctx, func(position *position) error {
-		_, span := logz.Span(ctx)
+		_, span := lg.Span(ctx)
 		defer span.End()
 
 		if position.size == es.AllEvents {
@@ -204,11 +217,17 @@ func (s *subscription) Recv(ctx context.Context) bool {
 		if position.size == 0 {
 			position.wait = make(chan struct{})
 			wait = func(ctx context.Context) bool {
-				ctx, span := logz.Span(ctx)
+				ctx, span := lg.Span(ctx)
 				defer span.End()
 
 				select {
 				case <-position.wait:
+					if position.link.SpanContext.IsValid() {
+						_, span := lg.Span(ctx, trace.WithLinks(position.link))
+						span.AddEvent("recv event")
+						span.End()
+						position.link = trace.Link{}
+					}
 
 					return true
 				case <-ctx.Done():
@@ -232,12 +251,12 @@ func (s *subscription) Recv(ctx context.Context) bool {
 	return true
 }
 func (s *subscription) Events(ctx context.Context) (event.Events, error) {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	var events event.Events
 	return events, s.position.Modify(ctx, func(position *position) error {
-		ctx, span := logz.Span(ctx)
+		ctx, span := lg.Span(ctx)
 		defer span.End()
 
 		var err error
@@ -253,7 +272,7 @@ func (s *subscription) Events(ctx context.Context) (event.Events, error) {
 	})
 }
 func (s *subscription) Close(ctx context.Context) error {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	return s.unsub(ctx)

pkg/es/es.go

@@ -6,7 +6,7 @@ import (
 	"fmt"
 	"strings"
 
-	"github.com/sour-is/ev/internal/logz"
+	"github.com/sour-is/ev/internal/lg"
 	"github.com/sour-is/ev/pkg/es/driver"
 	"github.com/sour-is/ev/pkg/es/event"
 	"github.com/sour-is/ev/pkg/locker"
@@ -25,11 +25,8 @@ var (
 	drivers = locker.New(&config{drivers: make(map[string]driver.Driver)})
 )
 
-func Register(ctx context.Context, name string, d driver.Driver) error {
+func Init(ctx context.Context) error {
-	ctx, span := logz.Span(ctx)
+	m := lg.Meter(ctx)
-	defer span.End()
-
-	m := logz.Meter(ctx)
 
 	var err, errs error
 	Mes_open, err = m.SyncInt64().Counter("es_open")
@@ -47,15 +44,20 @@ func Register(ctx context.Context, name string, d driver.Driver) error {
 	Mes_append, err = m.SyncInt64().Counter("es_append")
 	errs = multierr.Append(errs, err)
 
-	err = drivers.Modify(ctx, func(c *config) error {
+	return errs
+}
+
+func Register(ctx context.Context, name string, d driver.Driver) error {
+	ctx, span := lg.Span(ctx)
+	defer span.End()
+
+	return drivers.Modify(ctx, func(c *config) error {
 		if _, set := c.drivers[name]; set {
 			return fmt.Errorf("driver %s already set", name)
 		}
 		c.drivers[name] = d
 		return nil
 	})
-
-	return multierr.Append(errs, err)
 }
 
 type EventStore struct {
@@ -71,7 +73,7 @@ var (
 )
 
 func Open(ctx context.Context, dsn string, options ...Option) (*EventStore, error) {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	Mes_open.Add(ctx, 1)
@@ -107,7 +109,7 @@ type Option interface {
 }
 
 func (es *EventStore) Save(ctx context.Context, agg event.Aggregate) (uint64, error) {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	events := agg.Events(true)
@@ -131,7 +133,7 @@ func (es *EventStore) Save(ctx context.Context, agg event.Aggregate) (uint64, er
 	return count, err
 }
 func (es *EventStore) Load(ctx context.Context, agg event.Aggregate) error {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	Mes_load.Add(ctx, 1)
@@ -151,7 +153,7 @@ func (es *EventStore) Load(ctx context.Context, agg event.Aggregate) error {
 	return nil
 }
 func (es *EventStore) Read(ctx context.Context, streamID string, pos, count int64) (event.Events, error) {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	Mes_read.Add(ctx, 1)
@@ -163,7 +165,7 @@ func (es *EventStore) Read(ctx context.Context, streamID string, pos, count int6
 	return l.Read(ctx, pos, count)
 }
 func (es *EventStore) Append(ctx context.Context, streamID string, events event.Events) (uint64, error) {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	Mes_append.Add(ctx, 1)
@@ -175,7 +177,7 @@ func (es *EventStore) Append(ctx context.Context, streamID string, events event.
 	return l.Append(ctx, events, AppendOnly)
 }
 func (es *EventStore) FirstIndex(ctx context.Context, streamID string) (uint64, error) {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	l, err := es.Driver.EventLog(ctx, streamID)
@@ -185,7 +187,7 @@ func (es *EventStore) FirstIndex(ctx context.Context, streamID string) (uint64,
 	return l.FirstIndex(ctx)
 }
 func (es *EventStore) LastIndex(ctx context.Context, streamID string) (uint64, error) {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	l, err := es.Driver.EventLog(ctx, streamID)
@@ -231,7 +233,7 @@ type PE[T any] interface {
 
 // Create uses fn to create a new aggregate and store in db.
 func Create[A any, T PA[A]](ctx context.Context, es *EventStore, streamID string, fn func(context.Context, T) error) (agg T, err error) {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	agg = new(A)
@@ -261,7 +263,7 @@ func Create[A any, T PA[A]](ctx context.Context, es *EventStore, streamID string
 
 // Update uses fn to update an exsisting aggregate and store in db.
 func Update[A any, T PA[A]](ctx context.Context, es *EventStore, streamID string, fn func(context.Context, T) error) (agg T, err error) {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	agg = new(A)
@@ -288,7 +290,7 @@ func Update[A any, T PA[A]](ctx context.Context, es *EventStore, streamID string
 
 // Update uses fn to update an exsisting aggregate and store in db.
 func Upsert[A any, T PA[A]](ctx context.Context, es *EventStore, streamID string, fn func(context.Context, T) error) (agg T, err error) {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	agg = new(A)

pkg/es/event/events.go

@@ -1,11 +1,13 @@
 package event
 
 import (
+	"context"
 	"crypto/rand"
 	"encoding"
 	"encoding/json"
 	"fmt"
 	"io"
+	"strconv"
 	"strings"
 	"sync"
 	"time"
@@ -129,6 +131,10 @@ func (m Meta) Created() time.Time {
 }
 func (m Meta) GetEventID() string { return m.EventID.String() }
 
+func Init(ctx context.Context) error {
+	return Register(ctx, NilEvent, &eventPtr{})
+}
+
 type nilEvent struct{}
 
 func (*nilEvent) EventMeta() Meta {
@@ -144,3 +150,61 @@ func (e *nilEvent) MarshalBinary() ([]byte, error) {
 func (e *nilEvent) UnmarshalBinary(b []byte) error {
 	return json.Unmarshal(b, e)
 }
+
+type eventPtr struct {
+	streamID string
+	pos      uint64
+
+	eventMeta Meta
+}
+
+var _ Event = (*eventPtr)(nil)
+
+func NewPtr(streamID string, pos uint64) *eventPtr {
+	return &eventPtr{streamID: streamID, pos: pos}
+}
+
+// MarshalBinary implements Event
+func (e *eventPtr) MarshalBinary() (data []byte, err error) {
+	return []byte(fmt.Sprintf("%s@%d", e.streamID, e.pos)), nil
+}
+
+// UnmarshalBinary implements Event
+func (e *eventPtr) UnmarshalBinary(data []byte) error {
+	s := string(data)
+	idx := strings.LastIndex(s, "@")
+	if idx == -1 {
+		return fmt.Errorf("missing @ in: %s", s)
+	}
+	e.streamID = s[:idx]
+	var err error
+	e.pos, err = strconv.ParseUint(s[idx+1:], 10, 64)
+
+	return err
+}
+
+// EventMeta implements Event
+func (e *eventPtr) EventMeta() Meta {
+	if e == nil {
+		return Meta{}
+	}
+	return e.eventMeta
+}
+
+// SetEventMeta implements Event
+func (e *eventPtr) SetEventMeta(m Meta) {
+	if e == nil {
+		return
+	}
+	e.eventMeta = m
+}
+
+func (e *eventPtr) Values() any {
+	return struct {
+		StreamID string `json:"stream_id"`
+		Pos      uint64 `json:"pos"`
+	}{
+		e.streamID,
+		e.pos,
+	}
+}

pkg/es/event/reflect.go

@@ -9,7 +9,7 @@ import (
 	"reflect"
 	"strings"
 
-	"github.com/sour-is/ev/internal/logz"
+	"github.com/sour-is/ev/internal/lg"
 	"github.com/sour-is/ev/pkg/locker"
 )
 
@@ -67,7 +67,7 @@ func (u *UnknownEvent) MarshalBinary() ([]byte, error) {
 
 // Register a type container for Unmarshalling values into. The type must implement Event and not be a nil value.
 func Register(ctx context.Context, lis ...Event) error {
-	_, span := logz.Span(ctx)
+	_, span := lg.Span(ctx)
 	defer span.End()
 
 	for _, e := range lis {
@@ -84,7 +84,7 @@ func Register(ctx context.Context, lis ...Event) error {
 	return nil
 }
 func RegisterName(ctx context.Context, name string, e Event) error {
-	_, span := logz.Span(ctx)
+	_, span := lg.Span(ctx)
 	defer span.End()
 
 	if e == nil {
@@ -107,7 +107,7 @@ func RegisterName(ctx context.Context, name string, e Event) error {
 	span.AddEvent("register: " + name)
 
 	if err := eventTypes.Modify(ctx, func(c *config) error {
-		_, span := logz.Span(ctx)
+		_, span := lg.Span(ctx)
 		defer span.End()
 
 		c.eventTypes[name] = typ
@@ -119,13 +119,13 @@ func RegisterName(ctx context.Context, name string, e Event) error {
 	return nil
 }
 func GetContainer(ctx context.Context, s string) Event {
-	_, span := logz.Span(ctx)
+	_, span := lg.Span(ctx)
 	defer span.End()
 
 	var e Event
 
 	eventTypes.Modify(ctx, func(c *config) error {
-		_, span := logz.Span(ctx)
+		_, span := lg.Span(ctx)
 		defer span.End()
 
 		typ, ok := c.eventTypes[s]
@@ -176,7 +176,7 @@ func MarshalBinary(e Event) (txt []byte, err error) {
 }
 
 func UnmarshalBinary(ctx context.Context, txt []byte, pos uint64) (e Event, err error) {
-	_, span := logz.Span(ctx)
+	_, span := lg.Span(ctx)
 	defer span.End()
 
 	sp := bytes.SplitN(txt, []byte{'\t'}, 4)
@@ -262,7 +262,13 @@ func Values(e Event) map[string]any {
 		}
 
 		field := v.FieldByIndex(idx.Index)
-		m[idx.Name] = field.Interface()
+
+		name := idx.Name
+		if n, ok := idx.Tag.Lookup("json"); ok {
+			name = n
+		}
+
+		m[name] = field.Interface()
 	}
 	return m
 }

pkg/es/graph.go

@@ -6,7 +6,7 @@ import (
 	"net/http"
 	"time"
 
-	"github.com/sour-is/ev/internal/logz"
+	"github.com/sour-is/ev/internal/lg"
 	"github.com/sour-is/ev/pkg/es/event"
 	"github.com/sour-is/ev/pkg/gql"
 )
@@ -17,7 +17,7 @@ type EventResolver interface {
 }
 
 func (es *EventStore) Events(ctx context.Context, streamID string, paging *gql.PageInput) (*gql.Connection, error) {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	lis, err := es.Read(ctx, streamID, paging.GetIdx(0), paging.GetCount(30))
@@ -53,7 +53,7 @@ func (es *EventStore) Events(ctx context.Context, streamID string, paging *gql.P
 	}, nil
 }
 func (e *EventStore) EventAdded(ctx context.Context, streamID string, after int64) (<-chan *GQLEvent, error) {
-	ctx, span := logz.Span(ctx)
+	ctx, span := lg.Span(ctx)
 	defer span.End()
 
 	es := e.EventStream()
@@ -70,15 +70,19 @@ func (e *EventStore) EventAdded(ctx context.Context, streamID string, after int6
 	ch := make(chan *GQLEvent)
 
 	go func() {
-		ctx, span := logz.Span(ctx)
+		ctx, span := lg.Span(ctx)
 		defer span.End()
 
-		defer func() {
+		{
-			ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
+			ctx, span := lg.Fork(ctx)
-			defer cancel()
+			defer func() {
-			err := sub.Close(ctx)
+				defer span.End()
-			span.RecordError(err)
+				ctx, cancel := context.WithTimeout(ctx, 1*time.Second)
-		}()
+				defer cancel()
+				err := sub.Close(ctx)
+				span.RecordError(err)
+			}()
+		}
 
 		for sub.Recv(ctx) {
 			events, err := sub.Events(ctx)
@@ -109,7 +113,7 @@ type GQLEvent struct {
 }
 
 func (e *GQLEvent) ID() string {
-	return "Event/" + e.e.EventMeta().GetEventID()
+	return fmt.Sprint(e.e.EventMeta().StreamID, "@", e.e.EventMeta().Position)
 }
 func (e *GQLEvent) EventID() string {
 	return e.e.EventMeta().GetEventID()

pkg/locker/locker.go

@@ -2,6 +2,8 @@ package locker
 
 import (
 	"context"
+
+	"github.com/sour-is/ev/internal/lg"
 )
 
 type Locked[T any] struct {
@@ -18,6 +20,9 @@ func New[T any](initial *T) *Locked[T] {
 
 // Modify will call the function with the locked value
 func (s *Locked[T]) Modify(ctx context.Context, fn func(*T) error) error {
+	_, span := lg.Span(ctx)
+	defer span.End()
+
 	if ctx.Err() != nil {
 		return ctx.Err()
 	}

pkg/set/set.go

@@ -0,0 +1,35 @@
+package set
+
+import (
+	"fmt"
+	"strings"
+)
+
+type Set[T comparable] map[T]struct{}
+
+func New[T comparable](items ...T) Set[T] {
+	s := make(map[T]struct{}, len(items))
+	for i := range items {
+		s[items[i]] = struct{}{}
+	}
+	return s
+}
+func (s Set[T]) Has(v T) bool {
+	_, ok := (s)[v]
+	return ok
+}
+func (s Set[T]) String() string {
+	if s == nil {
+		return "set(<nil>)"
+	}
+	lis := make([]string, 0, len(s))
+	for k := range s {
+		lis = append(lis, fmt.Sprint(k))
+	}
+
+	var b strings.Builder
+	b.WriteString("set(")
+	b.WriteString(strings.Join(lis, ","))
+	b.WriteString(")")
+	return b.String()
+}