lib/debug: new package for debugging

The debug package provide global Value that is initialized from
environment variable "DEBUG".

User only need to include the package, and all initialization will be
handled by init().

1 files changed, 33 insertions, 0 deletions

diff --git a/lib/debug/debug.go b/lib/debug/debug.go
new file mode 100644
index 00000000..5c88c4d2
--- /dev/null
+++ b/lib/debug/debug.go
@@ -0,0 +1,33 @@
+// Copyright 2018, Shulhan <ms@kilabit.info>. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package debug provide global debug variable, initialized through
+// environment variable "DEBUG" or directly.
+package debug
+
+import (
+	"os"
+	"strconv"
+	"sync"
+)
+
+var (
+	// Value contains DEBUG value from environment.
+	Value = 0
+	once  sync.Once
+)
+
+func loadEnvironment() {
+	v := os.Getenv("DEBUG")
+	if len(v) > 0 {
+		Value, _ = strconv.Atoi(v)
+	}
+}
+
+//
+// init initialize debug from system environment.
+//
+func init() {
+	once.Do(loadEnvironment)
+}