From 27435a1e564b664466ab06a9b294092b67111009 Mon Sep 17 00:00:00 2001
From: Victor Vieux <victorvieux@gmail.com>
Date: Fri, 29 May 2015 16:48:02 -0700
Subject: [PATCH] no not print empty keys in docker info

Signed-off-by: Victor Vieux <victorvieux@gmail.com>
---
 ioutils/fmt.go      | 14 ++++++++++++++
 ioutils/fmt_test.go | 17 +++++++++++++++++
 2 files changed, 31 insertions(+)
 create mode 100644 ioutils/fmt.go
 create mode 100644 ioutils/fmt_test.go

diff --git a/ioutils/fmt.go b/ioutils/fmt.go
new file mode 100644
index 0000000..801132f
--- /dev/null
+++ b/ioutils/fmt.go
@@ -0,0 +1,14 @@
+package ioutils
+
+import (
+	"fmt"
+	"io"
+)
+
+// FprintfIfNotEmpty prints the string value if it's not empty
+func FprintfIfNotEmpty(w io.Writer, format, value string) (int, error) {
+	if value != "" {
+		return fmt.Fprintf(w, format, value)
+	}
+	return 0, nil
+}
diff --git a/ioutils/fmt_test.go b/ioutils/fmt_test.go
new file mode 100644
index 0000000..8968863
--- /dev/null
+++ b/ioutils/fmt_test.go
@@ -0,0 +1,17 @@
+package ioutils
+
+import "testing"
+
+func TestFprintfIfNotEmpty(t *testing.T) {
+	wc := NewWriteCounter(&NopWriter{})
+	n, _ := FprintfIfNotEmpty(wc, "foo%s", "")
+
+	if wc.Count != 0 || n != 0 {
+		t.Errorf("Wrong count: %v vs. %v vs. 0", wc.Count, n)
+	}
+
+	n, _ = FprintfIfNotEmpty(wc, "foo%s", "bar")
+	if wc.Count != 6 || n != 6 {
+		t.Errorf("Wrong count: %v vs. %v vs. 6", wc.Count, n)
+	}
+}