up to q

.gitignore

@@ -0,0 +1,2 @@
+/slack-bot-vr
+**/*.sw*

driver.go

@@ -9,9 +9,15 @@ import (
 	"go.etcd.io/bbolt"
 )
 
+type Driver interface {
+	Close() error
+	ForEach(context.Context, string, func(string, []byte) error) error
+	Get(context.Context, string, string) ([]byte, error)
+	Set(context.Context, string, string, []byte) error
+}
+
 type BBolt struct {
-	db  *bbolt.DB
-	bkt string
+	db *bbolt.DB
 }
 
 func NewTestDB() BBolt {
@@ -37,9 +43,9 @@ func (bb BBolt) Close() error {
 	return bb.db.Close()
 }
 
-func (bb BBolt) ForEach(ctx context.Context, cb func(string, []byte) error) error {
+func (bb BBolt) ForEach(ctx context.Context, db string, cb func(string, []byte) error) error {
 	return bb.db.View(func(tx *bbolt.Tx) error {
-		bkt := tx.Bucket([]byte(bb.bkt))
+		bkt := tx.Bucket([]byte(db))
 		if bkt == nil {
 			return nil
 		}
@@ -55,10 +61,10 @@ func (bb BBolt) ForEach(ctx context.Context, cb func(string, []byte) error) erro
 	})
 }
 
-func (bb BBolt) Get(_ context.Context, id string) ([]byte, error) {
+func (bb BBolt) Get(_ context.Context, db, id string) ([]byte, error) {
 	var b []byte
 	err := bb.db.View(func(tx *bbolt.Tx) error {
-		bkt := tx.Bucket([]byte(bb.bkt))
+		bkt := tx.Bucket([]byte(db))
 		if bkt == nil {
 			return nil
 		}
@@ -69,17 +75,20 @@ func (bb BBolt) Get(_ context.Context, id string) ([]byte, error) {
 	return b, err
 }
 
-func (bb BBolt) Set(_ context.Context, id string, value []byte) error {
+func (bb BBolt) Set(_ context.Context, db, id string, value []byte) error {
 	return bb.db.Update(func(tx *bbolt.Tx) error {
-		bkt := tx.Bucket([]byte(bb.bkt))
+		bkt := tx.Bucket([]byte(db))
 		if bkt == nil {
 			var err error
-			bkt, err = tx.CreateBucket([]byte(bb.bkt))
+			bkt, err = tx.CreateBucket([]byte(db))
 			if err != nil {
 				return err
 			}
 		}
 
+		if value == nil {
+			return bkt.Delete([]byte(id))
+		}
 		return bkt.Put([]byte(id), value)
 	})
 }

go.mod

@@ -2,6 +2,9 @@ module gitea/render/slack-bot-vr
 
 go 1.20
 
-require go.etcd.io/bbolt v1.3.9
+require (
+	github.com/go-errors/errors v1.5.1
+	go.etcd.io/bbolt v1.3.9
+)
 
 require golang.org/x/sys v0.4.0 // indirect

go.sum

@@ -1,4 +1,6 @@
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/go-errors/errors v1.5.1 h1:ZwEMSLRCapFLflTpT7NKaAc7ukJ8ZPEjzlxt8rPN8bk=
+github.com/go-errors/errors v1.5.1/go.mod h1:sIVyrIiJhuEF+Pj9Ebtd6P/rEYROXFi3BopGUQ5a5Og=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/stretchr/testify v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKsk=
 go.etcd.io/bbolt v1.3.9 h1:8x7aARPEXiXbHmtUwAIv7eV2fQFHrLLavdiJ3uzJXoI=

message.go

@@ -14,6 +14,10 @@ type Message struct {
 	AssetID   string
 }
 
+func (m Message) Empty() bool {
+	return m == (Message{})
+}
+
 func (m Message) Serialize() []byte {
 	b, err := json.Marshal(m)
 	if err != nil {

queue.go

@@ -0,0 +1,62 @@
+package main
+
+import (
+	"context"
+	"time"
+
+	"github.com/go-errors/errors"
+)
+
+type Queue struct {
+	driver Driver
+}
+
+func NewTestQueue() Queue {
+	return Queue{driver: NewTestDB()}
+}
+
+func NewQueue(driver Driver) Queue {
+	return Queue{driver: driver}
+}
+
+func (q Queue) Push(ctx context.Context, m Message) error {
+	return q.driver.Set(ctx, "q", m.ID, m.Serialize())
+}
+
+func (q Queue) PeekFirst(ctx context.Context) (Message, error) {
+	for {
+		m, err := q.peekFirst(ctx)
+		if err != nil {
+			return m, err
+		}
+
+		if !m.Empty() {
+			return m, nil
+		}
+
+		select {
+		case <-ctx.Done():
+			return Message{}, ctx.Err()
+		case <-time.After(time.Second):
+		}
+	}
+}
+
+func (q Queue) Ack(ctx context.Context, id string) error {
+	return q.driver.Set(ctx, "q", id, nil)
+}
+
+func (q Queue) peekFirst(ctx context.Context) (Message, error) {
+	var m Message
+	subctx, subcan := context.WithCancel(ctx)
+	defer subcan()
+	err := q.driver.ForEach(subctx, "q", func(_ string, value []byte) error {
+		m = MustDeserialize(value)
+		subcan()
+		return nil
+	})
+	if errors.Is(err, subctx.Err()) {
+		err = nil
+	}
+	return m, err
+}

storage.go

@@ -6,13 +6,6 @@ type Storage struct {
 	driver Driver
 }
 
-type Driver interface {
-	Close() error
-	ForEach(context.Context, func(string, []byte) error) error
-	Get(context.Context, string) ([]byte, error)
-	Set(context.Context, string, []byte) error
-}
-
 func NewTestStorage() Storage {
 	return Storage{driver: NewTestDB()}
 }
@@ -20,3 +13,9 @@ func NewTestStorage() Storage {
 func NewStorage(driver Driver) Storage {
 	return Storage{driver: driver}
 }
+
+func (s Storage) Enqueue(ctx context.Context, m Message) error {
+}
+
+func (s Storage) Dequeue(ctx context.Context, m Message) error {
+}