From 68bc8de111e4faa2a16583cd45b5c0fd253a3bba Mon Sep 17 00:00:00 2001
From: Erik Hollensbe <github@hollensbe.org>
Date: Fri, 24 Oct 2014 21:39:12 +0000
Subject: [PATCH] Test for updating hosts files via links.

Docker-DCO-1.1-Signed-off-by: Erik Hollensbe <github@hollensbe.org> (github: erikh)
---
 integration-cli/docker_cli_links_test.go | 37 ++++++++++++++++++++++++
 integration-cli/docker_utils.go          |  3 +-
 2 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/integration-cli/docker_cli_links_test.go b/integration-cli/docker_cli_links_test.go
index f202ce10a2..d412ef2a1a 100644
--- a/integration-cli/docker_cli_links_test.go
+++ b/integration-cli/docker_cli_links_test.go
@@ -6,6 +6,7 @@ import (
 	"os/exec"
 	"strings"
 	"testing"
+	"time"
 
 	"github.com/docker/docker/pkg/iptables"
 )
@@ -177,3 +178,39 @@ func TestLinksNotStartedParentNotFail(t *testing.T) {
 	}
 	logDone("link - container start not failing on updating stopped parent links")
 }
+
+func TestLinksHostsFilesInject(t *testing.T) {
+	defer deleteAllContainers()
+
+	out, _, err := runCommandWithOutput(exec.Command(dockerBinary, "run", "-itd", "--name", "one", "busybox", "top"))
+	if err != nil {
+		t.Fatal(err, out)
+	}
+
+	idOne := strings.TrimSpace(out)
+
+	out, _, err = runCommandWithOutput(exec.Command(dockerBinary, "run", "-itd", "--name", "two", "--link", "one:onetwo", "busybox", "top"))
+	if err != nil {
+		t.Fatal(err, out)
+	}
+
+	idTwo := strings.TrimSpace(out)
+
+	time.Sleep(1 * time.Second)
+
+	contentOne, err := readContainerFile(idOne, "hosts")
+	if err != nil {
+		t.Fatal(err, string(contentOne))
+	}
+
+	contentTwo, err := readContainerFile(idTwo, "hosts")
+	if err != nil {
+		t.Fatal(err, string(contentTwo))
+	}
+
+	if !strings.Contains(string(contentTwo), "onetwo") {
+		t.Fatal("Host is not present in updated hosts file", string(contentTwo))
+	}
+
+	logDone("link - ensure containers hosts files are updated with the link alias.")
+}
diff --git a/integration-cli/docker_utils.go b/integration-cli/docker_utils.go
index ca33baa2aa..9b5fa76c0c 100644
--- a/integration-cli/docker_utils.go
+++ b/integration-cli/docker_utils.go
@@ -736,10 +736,11 @@ func containerStorageFile(containerId, basename string) string {
 	return filepath.Join("/var/lib/docker/containers", containerId, basename)
 }
 
+// docker commands that use this function must be run with the '-d' switch.
 func runCommandAndReadContainerFile(filename string, cmd *exec.Cmd) ([]byte, error) {
 	out, _, err := runCommandWithOutput(cmd)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("%v: %q", err, out)
 	}
 
 	time.Sleep(1 * time.Second)