tests: Symlink volume tests

There was a known issue regarding how the symlink files mounted as
volumes were being handled on Windows. This commit adds tests that
will check against those issue to ensure there won't be any
regressions.

Signed-off-by: Claudiu Belu <cbelu@cloudbasesolutions.com>

integration/container_volume_test.go

@@ -0,0 +1,152 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package integration
+
+import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	runtime "k8s.io/cri-api/pkg/apis/runtime/v1alpha2"
+)
+
+func createRegularFile(basePath, content string) (string, error) {
+	newFolder := filepath.Join(basePath, "regular")
+	err := os.Mkdir(newFolder, 0755)
+	if err != nil {
+		return "", err
+	}
+
+	newFile := filepath.Join(newFolder, "foo.txt")
+	err = ioutil.WriteFile(newFile, []byte(content), 0644)
+	return filepath.Join("regular", "foo.txt"), err
+}
+
+func fileInSymlinkedFolder(basePath, targetFile string) (string, error) {
+	symlinkFolder := filepath.Join(basePath, "symlink_folder")
+	err := os.Symlink(filepath.Dir(targetFile), symlinkFolder)
+
+	return filepath.Join(symlinkFolder, filepath.Base(targetFile)), err
+}
+
+func symlinkedFile(basePath, targetFile string) (string, error) {
+	symlinkFile := filepath.Join(basePath, "symlink_file")
+	err := os.Symlink(targetFile, symlinkFile)
+
+	return symlinkFile, err
+}
+
+func symlinkedFileInSymlinkedFolder(basePath, targetFile string) (string, error) {
+	symlinkFolderFile, err := fileInSymlinkedFolder(basePath, targetFile)
+	if err != nil {
+		return "", err
+	}
+
+	return symlinkedFile(basePath, symlinkFolderFile)
+}
+
+func TestContainerSymlinkVolumes(t *testing.T) {
+	for name, testCase := range map[string]struct {
+		createFileFn func(basePath, targetFile string) (string, error)
+	}{
+		// Create difference file / symlink scenarios:
+		// - symlink_file -> regular_folder/regular_file
+		// - symlink_folder/regular_file (symlink_folder -> regular_folder)
+		// - symlink_file -> symlink_folder/regular_file (symlink_folder -> regular_folder)
+		"file in symlinked folder": {
+			createFileFn: fileInSymlinkedFolder,
+		},
+		"symlinked file": {
+			createFileFn: symlinkedFile,
+		},
+		"symlinkedFileInSymlinkedFolder": {
+			createFileFn: symlinkedFileInSymlinkedFolder,
+		},
+	} {
+		testCase := testCase // capture range variable
+		t.Run(name, func(t *testing.T) {
+			testPodLogDir, err := ioutil.TempDir("", "symlink-test")
+			require.NoError(t, err)
+			defer os.RemoveAll(testPodLogDir)
+
+			testVolDir, err := ioutil.TempDir("", "symlink-test-vol")
+			require.NoError(t, err)
+			defer os.RemoveAll(testVolDir)
+
+			content := "hello there\n"
+			regularFile, err := createRegularFile(testVolDir, content)
+			require.NoError(t, err)
+
+			file, err := testCase.createFileFn(testVolDir, regularFile)
+			require.NoError(t, err)
+
+			t.Log("Create test sandbox with log directory")
+			sbConfig := PodSandboxConfig("sandbox", "test-symlink",
+				WithPodLogDirectory(testPodLogDir),
+			)
+			sb, err := runtimeService.RunPodSandbox(sbConfig, *runtimeHandler)
+			require.NoError(t, err)
+			defer func() {
+				assert.NoError(t, runtimeService.StopPodSandbox(sb))
+				assert.NoError(t, runtimeService.RemovePodSandbox(sb))
+			}()
+
+			var (
+				testImage     = GetImage(BusyBox)
+				containerName = "test-container"
+			)
+
+			EnsureImageExists(t, testImage)
+
+			t.Log("Create a container with a symlink volume mount")
+			cnConfig := ContainerConfig(
+				containerName,
+				testImage,
+				WithCommand("cat", "/mounted_file"),
+				WithLogPath(containerName),
+				WithVolumeMount(file, "/mounted_file"),
+			)
+
+			cn, err := runtimeService.CreateContainer(sb, cnConfig, sbConfig)
+			require.NoError(t, err)
+
+			t.Log("Start the container")
+			require.NoError(t, runtimeService.StartContainer(cn))
+
+			t.Log("Wait for container to finish running")
+			require.NoError(t, Eventually(func() (bool, error) {
+				s, err := runtimeService.ContainerStatus(cn)
+				if err != nil {
+					return false, err
+				}
+				if s.GetState() == runtime.ContainerState_CONTAINER_EXITED {
+					return true, nil
+				}
+				return false, nil
+			}, time.Second, 30*time.Second))
+
+			output, err := ioutil.ReadFile(filepath.Join(testPodLogDir, containerName))
+			assert.NoError(t, err)
+
+			assert.Contains(t, string(output), content)
+		})
+	}
+}

integration/main_test.go

@@ -23,6 +23,7 @@ import (
 	"fmt"
 	"os"
 	"os/exec"
+	"path/filepath"
 	"strconv"
 	"strings"
 	"testing"
@@ -206,6 +207,15 @@ func WithResources(r *runtime.LinuxContainerResources) ContainerOpts { //nolint:
 	}
 }
 
+func WithVolumeMount(hostPath, containerPath string) ContainerOpts {
+	return func(c *runtime.ContainerConfig) {
+		hostPath, _ = filepath.Abs(hostPath)
+		containerPath, _ = filepath.Abs(containerPath)
+		mount := &runtime.Mount{HostPath: hostPath, ContainerPath: containerPath}
+		c.Mounts = append(c.Mounts, mount)
+	}
+}
+
 // Add container command.
 func WithCommand(cmd string, args ...string) ContainerOpts {
 	return func(c *runtime.ContainerConfig) {