Add database transactions to postgres repository

* Repository returns error when CreateBlock fails.

pkg/repositories/in_memory.go

@@ -24,8 +24,9 @@ func NewInMemory() *InMemory {
 	}
 }
 
-func (repository *InMemory) CreateBlock(block core.Block) {
+func (repository *InMemory) CreateBlock(block core.Block) error {
 	repository.blocks[block.Number] = &block
+	return nil
 }
 
 func (repository *InMemory) BlockCount() int {

pkg/repositories/postgres.go

@@ -3,6 +3,9 @@ package repositories
 import (
 	"database/sql"
 
+	"context"
+
+	"errors"
 	"github.com/8thlight/vulcanizedb/pkg/core"
 	"github.com/jmoiron/sqlx"
 	_ "github.com/lib/pq"
@@ -12,6 +15,10 @@ type Postgres struct {
 	Db *sqlx.DB
 }
 
+var (
+	ErrDBInsertFailed = errors.New("postgres: insert failed")
+)
+
 func (repository Postgres) MaxBlockNumber() int64 {
 	var highestBlockNumber int64
 	repository.Db.Get(&highestBlockNumber, `SELECT MAX(block_number) FROM blocks`)
@@ -57,26 +64,42 @@ func (repository Postgres) BlockCount() int {
 	return count
 }
 
-func (repository Postgres) CreateBlock(block core.Block) {
+func (repository Postgres) CreateBlock(block core.Block) error {
-	insertedBlock := repository.Db.QueryRow(
+	tx, _ := repository.Db.BeginTx(context.Background(), nil)
+	var blockId int64
+	err := tx.QueryRow(
 		`INSERT INTO blocks
 			(block_number, block_gaslimit, block_gasused, block_time, block_difficulty, block_hash, block_nonce, block_parenthash, block_size, uncle_hash)
-			VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10) RETURNING id`,
+			VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10)
-		block.Number, block.GasLimit, block.GasUsed, block.Time, block.Difficulty, block.Hash, block.Nonce, block.ParentHash, block.Size, block.UncleHash)
+		RETURNING id `,
-	var blockId int64
+		block.Number, block.GasLimit, block.GasUsed, block.Time, block.Difficulty, block.Hash, block.Nonce, block.ParentHash, block.Size, block.UncleHash).
-	insertedBlock.Scan(&blockId)
+		Scan(&blockId)
-	repository.createTransactions(blockId, block.Transactions)
+	if err != nil {
+		tx.Rollback()
+		return ErrDBInsertFailed
+	}
+	err = repository.createTransactions(tx, blockId, block.Transactions)
+	if err != nil {
+		tx.Rollback()
+		return ErrDBInsertFailed
+	}
+	tx.Commit()
+	return nil
 }
 
-func (repository Postgres) createTransactions(blockId int64, transactions []core.Transaction) {
+func (repository Postgres) createTransactions(tx *sql.Tx, blockId int64, transactions []core.Transaction) error {
 	for _, transaction := range transactions {
-		repository.Db.MustExec(
+		_, err := tx.Exec(
 			`INSERT INTO transactions
 			(block_id, tx_hash, tx_nonce, tx_to, tx_gaslimit, tx_gasprice, tx_value)
 			VALUES ($1, $2, $3, $4, $5, $6, $7)`,
 			blockId, transaction.Hash, transaction.Nonce, transaction.To, transaction.GasLimit, transaction.GasPrice, transaction.Value)
+		if err != nil {
+			return err
 		}
 	}
+	return nil
+}
 
 func (repository Postgres) loadBlock(blockRows *sql.Rows) core.Block {
 	var blockId int64
@@ -107,7 +130,7 @@ func (repository Postgres) loadBlock(blockRows *sql.Rows) core.Block {
 	}
 }
 func (repository Postgres) loadTransactions(blockId int64) []core.Transaction {
-	transactionRows, _ := repository.Db.Query("SELECT tx_hash, tx_nonce, tx_to, tx_gaslimit, tx_gasprice, tx_value FROM transactions")
+	transactionRows, _ := repository.Db.Query(`SELECT tx_hash, tx_nonce, tx_to, tx_gaslimit, tx_gasprice, tx_value FROM transactions`)
 	var transactions []core.Transaction
 	for transactionRows.Next() {
 		var hash string

pkg/repositories/repository.go

@@ -3,7 +3,7 @@ package repositories
 import "github.com/8thlight/vulcanizedb/pkg/core"
 
 type Repository interface {
-	CreateBlock(block core.Block)
+	CreateBlock(block core.Block) error
 	BlockCount() int
 	FindBlockByNumber(blockNumber int64) *core.Block
 	MaxBlockNumber() int64

pkg/repositories/repository_test.go

@@ -1,6 +1,9 @@
 package repositories_test
 
 import (
+	"fmt"
+	"strings"
+
 	"github.com/8thlight/vulcanizedb/pkg/config"
 	"github.com/8thlight/vulcanizedb/pkg/core"
 	"github.com/8thlight/vulcanizedb/pkg/repositories"
@@ -133,6 +136,7 @@ var _ = Describe("Repositories", func() {
 				Expect(savedTransaction.GasPrice).To(Equal(gasPrice))
 				Expect(savedTransaction.Value).To(Equal(value))
 			})
+
 		})
 
 		Describe("The missing block numbers", func() {
@@ -219,6 +223,48 @@ var _ = Describe("Repositories", func() {
 			Expect(db).ShouldNot(BeNil())
 		})
 
+		It("does not commit block if block is invalid", func() {
+
+			//badNonce violates db Nonce field length
+			badNonce := fmt.Sprintf("x %s", strings.Repeat("1", 100))
+			badBlock := core.Block{
+				Number:       123,
+				Nonce:        badNonce,
+				Transactions: []core.Transaction{},
+			}
+			pgConfig := config.DbConnectionString(config.NewConfig("private").Database)
+			db, _ := sqlx.Connect("postgres", pgConfig)
+			Expect(db).ShouldNot(BeNil())
+			repository := repositories.NewPostgres(db)
+
+			err := repository.CreateBlock(badBlock)
+			savedBlock := repository.FindBlockByNumber(123)
+
+			Expect(err).ToNot(BeNil())
+			Expect(savedBlock).To(BeNil())
+		})
+
+		It("does not commit block or transactions if transaction is invalid", func() {
+
+			//badHash violates db To field length
+			badHash := fmt.Sprintf("x %s", strings.Repeat("1", 100))
+			badTransaction := core.Transaction{To: badHash}
+			pgConfig := config.DbConnectionString(config.NewConfig("private").Database)
+			block := core.Block{
+				Number:       123,
+				Transactions: []core.Transaction{badTransaction},
+			}
+			db, _ := sqlx.Connect("postgres", pgConfig)
+			Expect(db).ShouldNot(BeNil())
+			repository := repositories.NewPostgres(db)
+
+			err := repository.CreateBlock(block)
+			savedBlock := repository.FindBlockByNumber(123)
+
+			Expect(err).ToNot(BeNil())
+			Expect(savedBlock).To(BeNil())
+		})
+
 		AssertRepositoryBehavior(func() repositories.Repository {
 			pgConfig := config.DbConnectionString(config.NewConfig("private").Database)
 			db, _ := sqlx.Connect("postgres", pgConfig)