Merge pull request #13 from tdadadavid/feat/blockchain_db

[Feat]: blockchain db

Author: tdadadavid

cmd/block_functions.go

@@ -1,6 +1,7 @@
 package cmd
 
 import (
+	"context"
 	"fmt"
 
 	"github.com/tdadadavid/block/pkg/chain"
@@ -9,7 +10,7 @@ import (
 var blockChain chain.Chain
 
 func init() {
-	blockChain = chain.New("/data/blocks")
+	blockChain = chain.New(context.Background(), "/data/blocks")
 }
 
 func printChain() {

pkg/chain/chain.go

@@ -1,6 +1,7 @@
 package chain
 
 import (
+	"context"
 	"encoding/json"
 	"fmt"
 
@@ -10,10 +11,12 @@ import (
 
 type Chain struct {
 	// store In memory database that stores the chain's data
-	store *BlockStore
+	store *ChainStore
 
 	// currentHash the current hash for this chain
 	currentHash string
+
+	chainCtx context.Context
 }
 
 // New creates a new chain
@@ -31,7 +34,7 @@ type Chain struct {
 //
 // Returns:
 //   - bc(Chain): The newly created chain
-func New(storagePath string) (bc Chain) {
+func New(ctx context.Context, storagePath string) (bc Chain) {
 	// Set the in-memory store for the chain and disable storage logs
 	options := badger.DefaultOptions("./../../data/blocks").WithLogger(nil)
 
@@ -40,8 +43,10 @@ func New(storagePath string) (bc Chain) {
 		panic(fmt.Errorf("failed to create chain %v", err))
 	}
 
-
-	bc = Chain{store: &BlockStore{store: store}}
+	bc = Chain{
+		chainCtx: ctx,
+		store:    &ChainStore{store: store},
+	}
 	bc.currentHash = bc.getLastHash()
 
 	return bc
@@ -55,7 +60,7 @@ func New(storagePath string) (bc Chain) {
 // Returns:
 //   - The hash of the block at "LAST" position
 func (c *Chain) getLastHash() string {
-	b := c.store.FindLastOrCreate()
+	b := c.store.FindLastOrCreate(c.chainCtx)
 	return b.GetHash()
 }
 
@@ -71,20 +76,20 @@ func (c *Chain) getLastHash() string {
 //   - Set the Chains hash to the new block's hash
 func (c *Chain) AddBlock(data string) {
 	// get previous block
-	prevBlock, err := c.store.FindLast()
+	prevBlock, err := c.store.FindLast(c.chainCtx)
 	if err != nil {
 		fmt.Printf("error while finding previous block: %s\n", err.Error())
 	}
 
 	// creates new block with previous block hash
 	newBlock := block.New(data, prevBlock.GetHash(), block.HashDifficulty) // create new block
-	err = c.store.Create(newBlock.GetHash(), newBlock)
+	err = c.store.Create(c.chainCtx, newBlock.GetHash(), newBlock)
 	if err != nil {
 		fmt.Printf("error while creating new block %v", err)
 	}
 
 	// update 'LAST' key in chain point to new block.
-	err = c.store.UpdateLast(newBlock)
+	err = c.store.UpdateLast(c.chainCtx, newBlock)
 	if err != nil {
 		fmt.Println("error while updating last block")
 	}
@@ -118,5 +123,5 @@ func (c *Chain) iter() ChainIterator {
 
 // Utility functions
 func (c *Chain) FindLast() (block.Block, error) {
-	return c.store.FindLast()
-}
+	return c.store.FindLast(c.chainCtx)
+}

pkg/chain/chain_test.go

@@ -1,6 +1,7 @@
 package chain
 
 import (
+	"context"
 	"os"
 	"testing"
 
@@ -19,15 +20,15 @@ func cleanUp(t *testing.T) {
 func TestBlockchain_New(t *testing.T) {
 	defer cleanUp(t)
 
-	bc := New("./../../data/blocks")
+	bc := New(context.Background(), "./../../data/blocks")
 	assert.NotNil(t, bc)
 }
 
 func TestBlockchain_AddBlock(t *testing.T) {
 	defer cleanUp(t)
 
 	// create blockchain
-	bc := New("./../../data/blocks")
+	bc := New(context.Background(), "./../../data/blocks")
 	assert.NotNil(t, bc)
 
 	// get prevHash (genesis block)
@@ -37,9 +38,11 @@ func TestBlockchain_AddBlock(t *testing.T) {
 	// add block
 	bc.AddBlock("test_data")
 
+	ctx := context.Background()
+	
 	iter := bc.iter()
-	for iter.HasNext() {
-		it := iter.Next()
+	for iter.HasNext(ctx) {
+		it := iter.Next(ctx)
 		if it == nil {
 			assert.Equal(t, "", iter.currentHash)
 		} else {

pkg/chain/iterator.go

@@ -1,11 +1,15 @@
 package chain
 
-import "github.com/tdadadavid/block/pkg/block"
+import (
+	"context"
+
+	"github.com/tdadadavid/block/pkg/block"
+)
 
 // Iterator captures the building block of any iterable
 type Iterator interface {
-	Next() *block.Block
-	HasNext() bool
+	Next(ctx context.Context) *block.Block
+	HasNext(ctx context.Context) bool
 }
 
 // ChainIterator Iterator used for moving through the chain it implements the Iterator interface
@@ -26,14 +30,14 @@ type ChainIterator struct {
 //
 // Returns:
 //   - bool: either true or false to signify if the iteration should continue
-func (it *ChainIterator) HasNext() bool {
+func (it *ChainIterator) HasNext(ctx context.Context) bool {
 	// if the chain is empty or the current hash is empty stop iteration
 	if it.blockchain == nil || it.currentHash == "" {
 		return false
 	}
 
 	// check if the block of the currentHash exists if it does the continue iteration else stop.
-	_, err := it.blockchain.store.FindByHash(it.currentHash)
+	_, err := it.blockchain.store.FindByHash(ctx, it.currentHash)
 	if err != nil {
 		return false
 	}
@@ -50,15 +54,15 @@ func (it *ChainIterator) HasNext() bool {
 //
 // Returns:
 //   - currBlock: The pointer to the current block from the database
-func (it *ChainIterator) Next() (curBlock *block.Block) {
+func (it *ChainIterator) Next(ctx context.Context) (curBlock *block.Block) {
 	// check if there is a next block on the chain
-	if !it.HasNext() {
+	if !it.HasNext(ctx) {
 		it.currentHash = ""
 		return curBlock
 	}
 
 	// find the current block using the current hash
-	b, err := it.blockchain.store.FindByHash(it.currentHash)
+	b, err := it.blockchain.store.FindByHash(ctx, it.currentHash)
 	if err != nil {
 		it.currentHash = ""
 		return curBlock

pkg/chain/store.go

@@ -14,27 +14,26 @@ var LastKey = []byte("LAST")
 type Storage interface {
 	FindLastOrCreate(ctx context.Context) block.Block
 	Create(ctx context.Context, key string, b block.Block) error
-	FindByHash(ctx context.Context, hash string) block.Block
+	FindByHash(ctx context.Context, hash string) (block.Block, error)
 	FindLast(ctx context.Context) (block.Block, error)
 	UpdateLast(ctx context.Context, b block.Block) error
 }
 
-type BlockStore struct {
+type ChainStore struct {
 	store *badger.DB
 }
 
-
-// findLastOrCreate used to get the last block in the chain or creates a new genesis block
+// FindLastOrCreate used to get the last block in the chain or creates a new genesis block
 //
 // Process:
 //   - Queries storage to get the block at the "LAST" position
 //   - If the block is not found then create the Genesis block for this chain, else returns the last found block
 //
 // Returns
 //   - last: The block at the "LAST" position
-func (bs *BlockStore) FindLastOrCreate() (last block.Block) {
+func (cs *ChainStore) FindLastOrCreate(ctx context.Context) (last block.Block) {
 	// try to findLast the block with the key 'LAST'
-	last, err := bs.FindLast()
+	last, err := cs.FindLast(ctx)
 	if err != nil {
 		//TODO: standardize logging
 		fmt.Printf("error finding last block err: [%s]\n", err.Error())
@@ -46,7 +45,7 @@ func (bs *BlockStore) FindLastOrCreate() (last block.Block) {
 		// if not found create the genesis block
 		fmt.Printf("creating new genesis block\n")
 		last = block.NewGenesisBlock()
-		err = bs.Create(string(LastKey), last)
+		err = cs.Create(ctx, string(LastKey), last)
 		if err != nil {
 			fmt.Printf("error while creating last item %s", err.Error())
 		}
@@ -67,8 +66,8 @@ func (bs *BlockStore) FindLastOrCreate() (last block.Block) {
 //
 // Returns
 //   - error: Returns the error during block creation process
-func (bs *BlockStore) Create(key string, b block.Block) error {
-	err := bs.store.Update(func(txn *badger.Txn) (err error) {
+func (cs *ChainStore) Create(ctx context.Context, key string, b block.Block) error {
+	err := cs.store.Update(func(txn *badger.Txn) (err error) {
 		data, err := b.Serialize()
 		if err != nil {
 			return err
@@ -82,7 +81,7 @@ func (bs *BlockStore) Create(key string, b block.Block) error {
 	return err
 }
 
-// findByHash finds a block by the given hash
+// FindByHash finds a block by the given hash
 //
 // Parameters:
 //   - hash(string): The hash of the block that we want to retrieve
@@ -94,9 +93,9 @@ func (bs *BlockStore) Create(key string, b block.Block) error {
 // Returns
 //   - b(block): Returns the block just found
 //   - err(error): Returns the error during block creation process
-func (bs *BlockStore) FindByHash(hash string) (b block.Block, err error) {
+func (cs *ChainStore) FindByHash(ctx context.Context, hash string) (b block.Block, err error) {
 	b = block.Block{}
-	err = bs.store.View(func(txn *badger.Txn) error {
+	err = cs.store.View(func(txn *badger.Txn) error {
 		lastBlock, err := txn.Get([]byte(hash))
 		if err != nil {
 			return err
@@ -110,7 +109,7 @@ func (bs *BlockStore) FindByHash(hash string) (b block.Block, err error) {
 	return b, err
 }
 
-// findByHash finds a block by the given hash
+// FindLast finds a block by the given hash
 //
 // Process:
 //   - Retrieves the block in bytes if it exists, else returns error
@@ -119,9 +118,9 @@ func (bs *BlockStore) FindByHash(hash string) (b block.Block, err error) {
 // Returns
 //   - block: Returns the block just found
 //   - error: Returns the error during block creation process
-func (bs *BlockStore) FindLast() (block.Block, error) {
+func (cs *ChainStore) FindLast(ctx context.Context) (block.Block, error) {
 	b := &block.Block{}
-	err := bs.store.View(func(txn *badger.Txn) error {
+	err := cs.store.View(func(txn *badger.Txn) error {
 		lastBlock, err := txn.Get(LastKey)
 		if err != nil {
 			return err
@@ -143,8 +142,8 @@ func (bs *BlockStore) FindLast() (block.Block, error) {
 //
 // Returns
 //   - error: Returns the error during update process
-func (bs *BlockStore) UpdateLast(b block.Block) (err error) {
-	err = bs.store.Update(func(txn *badger.Txn) error {
+func (cs *ChainStore) UpdateLast(ctx context.Context, b block.Block) (err error) {
+	err = cs.store.Update(func(txn *badger.Txn) error {
 		data, err := b.Serialize()
 		if err != nil {
 			return err