Improved error handeling

.env.example

@@ -0,0 +1,4 @@
+POSTGRES_HOST=localhost
+POSTGRES_DB=postgres
+POSTGRES_USER=postgres
+POSTGRES_PASSWORD=ito

db.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"fmt"
+	"log"
 
 	"github.com/ito-org/go-backend/tcn"
 	"github.com/jmoiron/sqlx"
@@ -20,7 +21,7 @@ func NewDBConnection(dbHost, dbUser, dbPassword, dbName string) (*DBConnection,
 
 	db, err := sqlx.Connect("postgres", connStr)
 	if err != nil {
-		fmt.Printf("Failed to connect to Postgres database: %s\n", err.Error())
+		log.Printf("Failed to connect to Postgres database: %s\n", err.Error())
 		return nil, err
 	}
 	return &DBConnection{db}, err
@@ -44,7 +45,7 @@ func (db *DBConnection) insertMemo(memo *tcn.Memo) (uint64, error) {
 		memo.Type,
 		memo.Data[:],
 	).Scan(&newID); err != nil {
-		fmt.Sprintf("Failed to insert memo into database: %s\n", err.Error())
+		log.Printf("Failed to insert memo into database: %s\n", err.Error())
 		return 0, err
 	}
 	return newID, nil

main.go

@@ -2,21 +2,29 @@ package main
 
 import (
 	"fmt"
+	"log"
 	"os"
 
 	"github.com/joho/godotenv"
 	"github.com/urfave/cli"
 )
 
-func readPostgresSettings(useEnvFile bool) (dbName, dbUser, dbPassword string) {
+func readPostgresSettings(useEnvFile bool) (dbHostname, dbName, dbUser, dbPassword string) {
 	if useEnvFile {
-		godotenv.Load()
+		err := godotenv.Load()
+		if err != nil {
+			log.Fatal("Error loading .env file")
+		}
 	}
 
+	dbHostname = os.Getenv("POSTGRES_HOSTNAME")
 	dbName = os.Getenv("POSTGRES_DB")
 	dbUser = os.Getenv("POSTGRES_USER")
 	dbPassword = os.Getenv("POSTGRES_PASSWORD")
 
+	if dbHostname == "" {
+		dbHostname = "localhost"
+	}
 	if dbName == "" {
 		dbName = "postgres"
 	}
@@ -33,7 +41,6 @@ func readPostgresSettings(useEnvFile bool) (dbName, dbUser, dbPassword string) {
 func main() {
 	var (
 		port       string
-		dbHost     string
 		useEnvFile bool
 	)
 
@@ -45,20 +52,14 @@ func main() {
 				Usage:       "Port for the server to run on",
 				Destination: &port,
 			},
-			&cli.StringFlag{
-				Name:        "dbhost",
-				Value:       "127.0.0.1",
-				Usage:       "The Postgres host to be used",
-				Destination: &dbHost,
-			},
 			&cli.BoolFlag{
 				Name:        "env",
 				Usage:       "Set to true to read from environment variable file",
 				Destination: &useEnvFile,
 			},
 		},
 		Action: func(ctx *cli.Context) error {
-			dbName, dbUser, dbPassword := readPostgresSettings(useEnvFile)
+			dbHost, dbName, dbUser, dbPassword := readPostgresSettings(useEnvFile)
 			dbConnection, err := NewDBConnection(dbHost, dbUser, dbPassword, dbName)
 			if err != nil {
 				return err
@@ -68,6 +69,6 @@ func main() {
 	}
 
 	if err := app.Run(os.Args); err != nil {
-		fmt.Println(err.Error())
+		log.Fatal(err.Error())
 	}
 }

server_test.go

@@ -26,9 +26,9 @@ func TestMain(m *testing.M) {
 	// requests. This allows us to create and the database connection which
 	// would otherwise not happen.
 
-	dbName, dbUser, dbPassword := readPostgresSettings(true)
+	dbHost, dbName, dbUser, dbPassword := readPostgresSettings(true)
 
-	dbConn, err := NewDBConnection("localhost", dbUser, dbPassword, dbName)
+	dbConn, err := NewDBConnection(dbHost, dbUser, dbPassword, dbName)
 	if err != nil {
 		panic(err.Error())
 	}

tcn/tcn.go

@@ -5,6 +5,7 @@ import (
 	"crypto/sha256"
 	"encoding/binary"
 	"errors"
+	"log"
 	"math"
 )
 
@@ -112,9 +113,18 @@ type TemporaryContactKey struct {
 // contact number.
 func (tck *TemporaryContactKey) Ratchet() (*TemporaryContactKey, error) {
 	nextHash := sha256.New()
-	nextHash.Write([]byte(HTCKDomainSep))
-	nextHash.Write(tck.RVK)
-	nextHash.Write(tck.TCKBytes[:])
+	_, err := nextHash.Write([]byte(HTCKDomainSep))
+	if err != nil {
+		log.Fatal("Could not write hash (HTCKDomainSep)")
+	}
+	_, err = nextHash.Write(tck.RVK)
+	if err != nil {
+		log.Fatal("Could not write hash (TVK)")
+	}
+	_, err = nextHash.Write(tck.TCKBytes[:])
+	if err != nil {
+		log.Fatal("Could not write hash (TCK)")
+	}
 
 	if tck.Index == math.MaxUint16 {
 		return nil, errors.New("rak should be rotated")