Remove fatal from pkg

* Functions in pkg should return errors
 * If aborting is desired, that behavior should be left to the consumer

pkg/config/config.go

@@ -1,7 +1,6 @@
 package config
 
 import (
-	"log"
 	"os"
 
 	"fmt"
@@ -50,8 +49,9 @@ func parseConfigFile(filePath string) (*Config, error) {
 	if err != nil {
 		return nil, err
 	} else {
-		if _, err := toml.DecodeFile(filePath, &cfg); err != nil {
-			log.Fatal(err)
+		_, err := toml.DecodeFile(filePath, &cfg)
+		if err != nil {
+			return nil, err
 		}
 		return &cfg, err
 	}

pkg/repositories/postgres.go

@@ -2,7 +2,6 @@ package repositories
 
 import (
 	"database/sql"
-	"log"
 
 	"context"
 
@@ -19,16 +18,17 @@ type Postgres struct {
 }
 
 var (
-	ErrDBInsertFailed = errors.New("postgres: insert failed")
+	ErrDBInsertFailed     = errors.New("postgres: insert failed")
+	ErrDBConnectionFailed = errors.New("postgres: db connection failed")
 )
 
-func NewPostgres(databaseConfig config.Database) Postgres {
+func NewPostgres(databaseConfig config.Database) (Postgres, error) {
 	connectString := config.DbConnectionString(databaseConfig)
 	db, err := sqlx.Connect("postgres", connectString)
 	if err != nil {
-		log.Fatalf("Error connecting to DB: %v\n", err)
+		return Postgres{}, ErrDBConnectionFailed
 	}
-	return Postgres{Db: db}
+	return Postgres{Db: db}, nil
 }
 
 func (repository Postgres) CreateWatchedContract(contract core.WatchedContract) error {
@@ -42,11 +42,8 @@ func (repository Postgres) CreateWatchedContract(contract core.WatchedContract)
 
 func (repository Postgres) IsWatchedContract(contractHash string) bool {
 	var exists bool
-	err := repository.Db.QueryRow(
+	repository.Db.QueryRow(
 		`SELECT exists(SELECT 1 FROM watched_contracts WHERE contract_hash=$1) FROM watched_contracts`, contractHash).Scan(&exists)
-	if err != nil && err != sql.ErrNoRows {
-		log.Fatalf("error checking if row exists %v", err)
-	}
 	return exists
 }
 

pkg/repositories/postgres_test.go

@@ -26,7 +26,7 @@ var _ = Describe("Postgres repository", func() {
 
 	testing.AssertRepositoryBehavior(func() repositories.Repository {
 		cfg, _ := config.NewConfig("private")
-		repository := repositories.NewPostgres(cfg.Database)
+		repository, _ := repositories.NewPostgres(cfg.Database)
 		testing.ClearData(repository)
 		return repository
 	})
@@ -40,7 +40,7 @@ var _ = Describe("Postgres repository", func() {
 			Transactions: []core.Transaction{},
 		}
 		cfg, _ := config.NewConfig("private")
-		repository := repositories.NewPostgres(cfg.Database)
+		repository, _ := repositories.NewPostgres(cfg.Database)
 
 		err := repository.CreateBlock(badBlock)
 		savedBlock := repository.FindBlockByNumber(123)
@@ -49,6 +49,12 @@ var _ = Describe("Postgres repository", func() {
 		Expect(savedBlock).To(BeNil())
 	})
 
+	It("throws error when can't connect to the database", func() {
+		invalidDatabase := config.Database{}
+		_, err := repositories.NewPostgres(invalidDatabase)
+		Expect(err).To(Equal(repositories.ErrDBConnectionFailed))
+	})
+
 	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))
@@ -58,7 +64,7 @@ var _ = Describe("Postgres repository", func() {
 			Transactions: []core.Transaction{badTransaction},
 		}
 		cfg, _ := config.NewConfig("private")
-		repository := repositories.NewPostgres(cfg.Database)
+		repository, _ := repositories.NewPostgres(cfg.Database)
 
 		err := repository.CreateBlock(block)
 		savedBlock := repository.FindBlockByNumber(123)