Add BlockchainDBObserver

* First code that interacts

.travis.yml

@@ -1,5 +1,16 @@
+dist: trusty
+sudo: required
 language: go
 go:
   - 1.9
+services:
+  - postgresql
+before_script:
+  - go get -u -d github.com/mattes/migrate/cli github.com/lib/pq
+  - go build -tags 'postgres' -o /usr/local/bin/migrate github.com/mattes/migrate/cli
+  - psql -c 'create database vulcanize;' -U postgres
+  - migrate -database 'postgresql://localhost:5432/vulcanize?sslmode=disable' -path ./migrations up
 script:
   - go test -v ./core/...
+notifications:
+  email: false

Gopkg.lock

@@ -19,6 +19,18 @@
   revision = "817915b46b97fd7bb80e8ab6b69f01a53ac3eebf"
   version = "v1.6.0"
 
+[[projects]]
+  branch = "master"
+  name = "github.com/jmoiron/sqlx"
+  packages = [".","reflectx"]
+  revision = "3379e5993990b1f927fc8db926485e6f6becf2d2"
+
+[[projects]]
+  branch = "master"
+  name = "github.com/lib/pq"
+  packages = [".","oid"]
+  revision = "b609790bd85edf8e9ab7e0f8912750a786177bcf"
+
 [[projects]]
   name = "github.com/onsi/ginkgo"
   packages = [".","config","internal/codelocation","internal/containernode","internal/failer","internal/leafnodes","internal/remote","internal/spec","internal/spec_iterator","internal/specrunner","internal/suite","internal/testingtproxy","internal/writer","reporters","reporters/stenographer","reporters/stenographer/support/go-colorable","reporters/stenographer/support/go-isatty","types"]
@@ -88,6 +100,6 @@
 [solve-meta]
   analyzer-name = "dep"
   analyzer-version = 1
-  inputs-digest = "1f89d2d001b1d5929ecd9f83d34d67edc4c1ae8baea497f4b5b76d9f6cc7f8d5"
+  inputs-digest = "28c66c62724453afdc526c6cf9de955240b487fb81b027fefbe7ed4e1545caec"
   solver-name = "gps-cdcl"
   solver-version = 1

Gopkg.toml

@@ -28,3 +28,7 @@
 [[constraint]]
   branch = "master"
   name = "github.com/jmoiron/sqlx"
+
+[[constraint]]
+  branch = "master"
+  name = "github.com/lib/pq"

core/blockchain_db_observer.go

@@ -0,0 +1,19 @@
+package core
+
+import (
+	"github.com/jmoiron/sqlx"
+	_ "github.com/lib/pq"
+)
+
+type BlockRecord struct {
+	BlockNumber int64 `db:"block_number"`
+}
+
+type BlockchainDBObserver struct {
+	Db *sqlx.DB
+}
+
+func (observer BlockchainDBObserver) NotifyBlockAdded(block Block) {
+	observer.Db.NamedExec("INSERT INTO blocks (block_number) VALUES (:block_number)", &BlockRecord{BlockNumber: block.Number.Int64()})
+	//observer.Db.MustExec("Insert INTO blocks (block_number) VALUES ($1)", block.Number.Int64())
+}

core/blockchain_db_observer_test.go

@@ -0,0 +1,72 @@
+package core_test
+
+import (
+	"math/big"
+
+	"fmt"
+
+	"github.com/8thlight/vulcanizedb/core"
+	"github.com/jmoiron/sqlx"
+	_ "github.com/lib/pq"
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+const (
+	host     = "localhost"
+	port     = 5432
+	user     = "postgres"
+	password = "postgres"
+	dbname   = "vulcanize"
+)
+
+var _ = Describe("Saving blocks to the database", func() {
+
+	var db *sqlx.DB
+	var err error
+
+	BeforeEach(func() {
+		pgConfig := fmt.Sprintf(
+			"host=%s port=%d user=%s password=%s dbname=%s sslmode=disable",
+			host, port, user, password, dbname)
+		db, err = sqlx.Connect("postgres", pgConfig)
+		db.MustExec("DELETE FROM blocks")
+	})
+
+	It("implements the observer interface", func() {
+		var observer core.BlockchainObserver = core.BlockchainDBObserver{Db: db}
+		Expect(observer).NotTo(BeNil())
+	})
+
+	It("connects to the database", func() {
+		Expect(err).Should(BeNil())
+		Expect(db).ShouldNot(BeNil())
+	})
+
+	It("starts with no blocks", func() {
+		var count int
+		queryError := db.Get(&count, "SELECT COUNT(*) FROM blocks")
+		Expect(queryError).Should(BeNil())
+		Expect(count).Should(Equal(0))
+	})
+
+	It("inserts a block", func() {
+		block := core.Block{Number: big.NewInt(1)}
+
+		observer := core.BlockchainDBObserver{Db: db}
+		observer.NotifyBlockAdded(block)
+
+		rows, err := db.Queryx("SELECT * FROM blocks")
+		Expect(err).To(BeNil())
+		var savedBlocks []core.BlockRecord
+		for rows.Next() {
+			var savedBlock core.BlockRecord
+			rows.StructScan(&savedBlock)
+			savedBlocks = append(savedBlocks, savedBlock)
+		}
+
+		Expect(len(savedBlocks)).To(Equal(1))
+		Expect(savedBlocks[0].BlockNumber).To(Equal(int64(1)))
+	})
+
+})

main.go

@@ -2,7 +2,11 @@ package main
 
 import (
 	"flag"
+
+	"log"
+
 	"github.com/8thlight/vulcanizedb/core"
+	"github.com/jmoiron/sqlx"
 )
 
 func main() {
@@ -11,5 +15,11 @@ func main() {
 
 	var blockchain core.Blockchain = core.NewGethBlockchain(*ipcPath)
 	blockchain.RegisterObserver(core.BlockchainLoggingObserver{})
+	pgConfig := "host=localhost port=5432 dbname=vulcanize sslmode=disable"
+	db, err := sqlx.Connect("postgres", pgConfig)
+	if err != nil {
+		log.Fatalf("Error connecting to DB: %v\n", err)
+	}
+	blockchain.RegisterObserver(core.BlockchainDBObserver{Db: db})
 	blockchain.SubscribeToEvents()
 }