initial commit

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

@@ -0,0 +1,232 @@
+package ds_driver
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/tidwall/wal"
+
+	"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/math"
+)
+
+type diskStore struct {
+	path string
+}
+
+var _ driver.Driver = (*diskStore)(nil)
+
+func Init(ctx context.Context) {
+	es.Register(ctx, "file", &diskStore{})
+}
+
+func (diskStore) Open(dsn string) (driver.EventStore, error) {
+	scheme, path, ok := strings.Cut(dsn, ":")
+	if !ok {
+		return nil, fmt.Errorf("expected scheme")
+	}
+
+	if scheme != "file" {
+		return nil, fmt.Errorf("expeted scheme=file, got=%s", scheme)
+	}
+
+	if _, err := os.Stat(path); os.IsNotExist(err) {
+		err = os.MkdirAll(path, 0700)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return &diskStore{path: path}, nil
+}
+
+func (es *diskStore) Save(ctx context.Context, agg event.Aggregate) (uint64, error) {
+	l, err := es.readLog(agg.StreamID())
+	if err != nil {
+		return 0, err
+	}
+
+	var last uint64
+
+	if last, err = l.w.LastIndex(); err != nil {
+		return 0, err
+	}
+
+	if agg.StreamVersion() != last {
+		return 0, fmt.Errorf("current version wrong %d != %d", agg.StreamVersion(), last)
+	}
+
+	events := agg.Events(true)
+
+	var b []byte
+	batch := &wal.Batch{}
+	for _, e := range events {
+		b, err = event.MarshalText(e)
+		if err != nil {
+			return 0, err
+		}
+
+		batch.Write(e.EventMeta().Position, b)
+	}
+
+	err = l.w.WriteBatch(batch)
+	if err != nil {
+		return 0, err
+	}
+	agg.Commit()
+
+	return uint64(len(events)), nil
+}
+func (es *diskStore) Append(ctx context.Context, streamID string, events event.Events) (uint64, error) {
+	event.SetStreamID(streamID, events...)
+
+	l, err := es.readLog(streamID)
+	if err != nil {
+		return 0, err
+	}
+
+	var last uint64
+
+	if last, err = l.w.LastIndex(); err != nil {
+		return 0, err
+	}
+
+	var b []byte
+
+	batch := &wal.Batch{}
+	for i, e := range events {
+		b, err = event.MarshalText(e)
+		if err != nil {
+			return 0, err
+		}
+		pos := last + uint64(i) + 1
+		event.SetPosition(e, pos)
+
+		batch.Write(pos, b)
+	}
+
+	err = l.w.WriteBatch(batch)
+	if err != nil {
+		return 0, err
+	}
+	return uint64(len(events)), nil
+}
+func (es *diskStore) Load(ctx context.Context, agg event.Aggregate) error {
+	l, err := es.readLog(agg.StreamID())
+	if err != nil {
+		return err
+	}
+
+	var i, first, last uint64
+
+	if first, err = l.w.FirstIndex(); err != nil {
+		return err
+	}
+	if last, err = l.w.LastIndex(); err != nil {
+		return err
+	}
+
+	if first == 0 || last == 0 {
+		return nil
+	}
+
+	var b []byte
+	events := make([]event.Event, last-i)
+
+	for i = 0; first+i <= last; i++ {
+		b, err = l.w.Read(first + i)
+		if err != nil {
+			return err
+		}
+		events[i], err = event.UnmarshalText(b, first+i)
+		if err != nil {
+			return err
+		}
+	}
+
+	event.Append(agg, events...)
+
+	return nil
+}
+func (es *diskStore) Read(ctx context.Context, streamID string, pos, count int64) (event.Events, error) {
+	l, err := es.readLog(streamID)
+	if err != nil {
+		return nil, err
+	}
+
+	var first, last, start uint64
+
+	if first, err = l.w.FirstIndex(); err != nil {
+		return nil, err
+	}
+	if last, err = l.w.LastIndex(); err != nil {
+		return nil, err
+	}
+
+	if first == 0 || last == 0 {
+		return nil, nil
+	}
+
+	switch {
+	case pos >= 0:
+		start = first + uint64(pos)
+		if pos == 0 && count < 0 {
+			count = -count // if pos=0 assume forward count.
+		}
+	case pos < 0:
+		start = uint64(int64(last) + pos + 1)
+		if pos == -1 && count > 0 {
+			count = -count // if pos=-1 assume backward count.
+		}
+	}
+
+	events := make([]event.Event, math.Abs(count))
+	for i := range events {
+		var b []byte
+
+		b, err = l.w.Read(start)
+		if err != nil {
+			return events, err
+		}
+		events[i], err = event.UnmarshalText(b, start)
+		if err != nil {
+			return events, err
+		}
+
+		if count > 0 {
+			start += 1
+		} else {
+			start -= 1
+		}
+		if start < first || start > last {
+			events = events[:i+1]
+			break
+		}
+	}
+
+	event.SetStreamID(streamID, events...)
+
+	return events, nil
+}
+
+func (es *diskStore) readLog(name string) (*eventLog, error) {
+	return newEventLog(name, filepath.Join(es.path, name))
+}
+
+type eventLog struct {
+	name string
+	path string
+	w    *wal.Log
+}
+
+func newEventLog(name, path string) (*eventLog, error) {
+	var err error
+	el := &eventLog{name: name, path: path}
+	el.w, err = wal.Open(path, wal.DefaultOptions)
+	return el, err
+}

pkg/es/driver/driver.go

@@ -0,0 +1,18 @@
+package driver
+
+import (
+	"context"
+
+	"github.com/sour-is/ev/pkg/es/event"
+)
+
+type Driver interface {
+	Open(string) (EventStore, error)
+}
+
+type EventStore interface {
+	Save(ctx context.Context, agg event.Aggregate) (uint64, error)
+	Load(ctx context.Context, agg event.Aggregate) error
+	Read(ctx context.Context, streamID string, pos, count int64) (event.Events, error)
+	Append(ctx context.Context, streamID string, events event.Events) (uint64, error)
+}