First commit

helper/crypto.go

@@ -0,0 +1,38 @@
+// Copyright 2017 Frédéric Guillot. All rights reserved.
+// Use of this source code is governed by the Apache 2.0
+// license that can be found in the LICENSE file.
+
+package helper
+
+import (
+	"crypto/rand"
+	"crypto/sha256"
+	"encoding/base64"
+	"fmt"
+)
+
+// HashFromBytes returns a SHA-256 checksum of the input.
+func HashFromBytes(value []byte) string {
+	sum := sha256.Sum256(value)
+	return fmt.Sprintf("%x", sum)
+}
+
+// Hash returns a SHA-256 checksum of a string.
+func Hash(value string) string {
+	return HashFromBytes([]byte(value))
+}
+
+// GenerateRandomBytes returns random bytes.
+func GenerateRandomBytes(size int) []byte {
+	b := make([]byte, size)
+	if _, err := rand.Read(b); err != nil {
+		panic(fmt.Errorf("Unable to generate random string: %v", err))
+	}
+
+	return b
+}
+
+// GenerateRandomString returns a random string.
+func GenerateRandomString(size int) string {
+	return base64.URLEncoding.EncodeToString(GenerateRandomBytes(size))
+}

helper/time.go

@@ -0,0 +1,16 @@
+// Copyright 2017 Frédéric Guillot. All rights reserved.
+// Use of this source code is governed by the Apache 2.0
+// license that can be found in the LICENSE file.
+
+package helper
+
+import (
+	"log"
+	"time"
+)
+
+// ExecutionTime returns the elapsed time of a block of code.
+func ExecutionTime(start time.Time, name string) {
+	elapsed := time.Since(start)
+	log.Printf("%s took %s", name, elapsed)
+}