Postage BatchStore and BatchService (#1070)

Co-authored-by: zelig <viktor.tron@gmail.com>

pkg/postage/batch.go

@@ -0,0 +1,43 @@
+// Copyright 2020 The Swarm Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package postage
+
+import (
+	"encoding/binary"
+	"math/big"
+)
+
+// Batch represents a postage batch, a payment on the blockchain.
+type Batch struct {
+	ID    []byte   // batch ID
+	Value *big.Int // overall balance of the batch
+	Start uint64   // block number the batch was created
+	Owner []byte   // owner's ethereum address
+	Depth uint8    // batch depth, i.e., size = 2^{depth}
+}
+
+// MarshalBinary implements BinaryMarshaller. It will attempt to serialize the
+// postage batch to a byte slice.
+func (b *Batch) MarshalBinary() ([]byte, error) {
+	out := make([]byte, 93)
+	copy(out, b.ID)
+	value := b.Value.Bytes()
+	copy(out[64-len(value):], value)
+	binary.BigEndian.PutUint64(out[64:72], b.Start)
+	copy(out[72:], b.Owner)
+	out[92] = b.Depth
+	return out, nil
+}
+
+// UnmarshalBinary implements BinaryUnmarshaller. It will attempt deserialize
+// the given byte slice into the batch.
+func (b *Batch) UnmarshalBinary(buf []byte) error {
+	b.ID = buf[:32]
+	b.Value = big.NewInt(0).SetBytes(buf[32:64])
+	b.Start = binary.BigEndian.Uint64(buf[64:72])
+	b.Owner = buf[72:92]
+	b.Depth = buf[92]
+	return nil
+}

pkg/postage/batch_test.go

@@ -0,0 +1,46 @@
+// Copyright 2020 The Swarm Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package postage_test
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/ethersphere/bee/pkg/postage"
+	postagetesting "github.com/ethersphere/bee/pkg/postage/testing"
+)
+
+// TestBatchMarshalling tests the idempotence  of binary marshal/unmarshal for a
+// Batch.
+func TestBatchMarshalling(t *testing.T) {
+	a := postagetesting.MustNewBatch()
+
+	buf, err := a.MarshalBinary()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(buf) != 93 {
+		t.Fatalf("invalid length for serialised batch. expected 93, got %d", len(buf))
+	}
+	b := &postage.Batch{}
+	if err := b.UnmarshalBinary(buf); err != nil {
+		t.Fatalf("unexpected error unmarshalling batch: %v", err)
+	}
+	if !bytes.Equal(b.ID, a.ID) {
+		t.Fatalf("id mismatch, expected %x, got %x", a.ID, b.ID)
+	}
+	if !bytes.Equal(b.Owner, a.Owner) {
+		t.Fatalf("owner mismatch, expected %x, got %x", a.Owner, b.Owner)
+	}
+	if a.Value.Uint64() != b.Value.Uint64() {
+		t.Fatalf("value mismatch, expected %d, got %d", a.Value.Uint64(), b.Value.Uint64())
+	}
+	if a.Start != b.Start {
+		t.Fatalf("start mismatch, expected %d, got %d", a.Start, b.Start)
+	}
+	if a.Depth != b.Depth {
+		t.Fatalf("depth mismatch, expected %d, got %d", a.Depth, b.Depth)
+	}
+}

pkg/postage/batchservice/batchservice.go

@@ -0,0 +1,107 @@
+// Copyright 2020 The Swarm Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package batchservice
+
+import (
+	"encoding/hex"
+	"fmt"
+	"math/big"
+
+	"github.com/ethersphere/bee/pkg/logging"
+	"github.com/ethersphere/bee/pkg/postage"
+)
+
+type batchService struct {
+	cs     *postage.ChainState
+	storer postage.Storer
+	logger logging.Logger
+}
+
+// New will create a new BatchService.
+func New(storer postage.Storer, logger logging.Logger) (postage.EventUpdater, error) {
+	b := &batchService{
+		storer: storer,
+		logger: logger,
+	}
+
+	cs, err := storer.GetChainState()
+	if err != nil {
+		return nil, fmt.Errorf("get chain state: %w", err)
+	}
+	b.cs = cs
+
+	return b, nil
+}
+
+// Create will create a new batch with the given ID, owner value and depth and
+// stores it in the BatchStore.
+func (svc *batchService) Create(id, owner []byte, value *big.Int, depth uint8) error {
+	b := &postage.Batch{
+		ID:    id,
+		Owner: owner,
+		Value: value,
+		Start: svc.cs.Block,
+		Depth: depth,
+	}
+
+	err := svc.storer.Put(b)
+	if err != nil {
+		return fmt.Errorf("put: %w", err)
+	}
+
+	svc.logger.Debugf("created batch id %s", hex.EncodeToString(b.ID))
+	return nil
+}
+
+// TopUp implements the EventUpdater interface. It tops ups a batch with the
+// given ID with the given amount.
+func (svc *batchService) TopUp(id []byte, amount *big.Int) error {
+	b, err := svc.storer.Get(id)
+	if err != nil {
+		return fmt.Errorf("get: %w", err)
+	}
+
+	b.Value.Add(b.Value, amount)
+
+	err = svc.storer.Put(b)
+	if err != nil {
+		return fmt.Errorf("put: %w", err)
+	}
+
+	svc.logger.Debugf("topped up batch id %s with %v", hex.EncodeToString(b.ID), b.Value)
+	return nil
+}
+
+// UpdateDepth implements the EventUpdater inteface. It sets the new depth of a
+// batch with the given ID.
+func (svc *batchService) UpdateDepth(id []byte, depth uint8) error {
+	b, err := svc.storer.Get(id)
+	if err != nil {
+		return fmt.Errorf("get: %w", err)
+	}
+
+	b.Depth = depth
+
+	err = svc.storer.Put(b)
+	if err != nil {
+		return fmt.Errorf("put: %w", err)
+	}
+
+	svc.logger.Debugf("updated depth of batch id %s to %d", hex.EncodeToString(b.ID), b.Depth)
+	return nil
+}
+
+// UpdatePrice implements the EventUpdater interface. It sets the current
+// price from the chain in the service chain state.
+func (svc *batchService) UpdatePrice(price *big.Int) error {
+	svc.cs.Price = price
+
+	if err := svc.storer.PutChainState(svc.cs); err != nil {
+		return fmt.Errorf("put chain state: %w", err)
+	}
+
+	svc.logger.Debugf("updated chain price to %s", svc.cs.Price)
+	return nil
+}