runtime: optimize test code

This PR includes these optimize changes:

- Remove the dependency on the container engine.
  The old code uses runc to generate config.json and
  Docker to export rootfs, that will be heavy and need
  additional dependency.
  Using a fixed config for busybox image can avoid
  the heavy processing above.

- Moved duplicate code to pkg/katatestutils package

Fixes: #2752

Signed-off-by: bin <bin@hyper.sh>

src/runtime/pkg/katatestutils/utils.go

@@ -7,8 +7,203 @@
 package katatestutils
 
 import (
+	"encoding/json"
+	"errors"
+	"io/ioutil"
 	"os"
+	"path/filepath"
 	"strconv"
+	"testing"
+
+	"github.com/opencontainers/runtime-spec/specs-go"
+	"github.com/stretchr/testify/assert"
+)
+
+const (
+	testDirMode  = os.FileMode(0750)
+	testFileMode = os.FileMode(0640)
+
+	busyboxConfigJson = `
+{
+	"ociVersion": "1.0.1-dev",
+	"process": {
+		"terminal": true,
+		"user": {
+			"uid": 0,
+			"gid": 0
+		},
+		"args": [
+			"sh"
+		],
+		"env": [
+			"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
+			"TERM=xterm"
+		],
+		"cwd": "/",
+		"capabilities": {
+			"bounding": [
+				"CAP_AUDIT_WRITE",
+				"CAP_KILL",
+				"CAP_NET_BIND_SERVICE"
+			],
+			"effective": [
+				"CAP_AUDIT_WRITE",
+				"CAP_KILL",
+				"CAP_NET_BIND_SERVICE"
+			],
+			"inheritable": [
+				"CAP_AUDIT_WRITE",
+				"CAP_KILL",
+				"CAP_NET_BIND_SERVICE"
+			],
+			"permitted": [
+				"CAP_AUDIT_WRITE",
+				"CAP_KILL",
+				"CAP_NET_BIND_SERVICE"
+			],
+			"ambient": [
+				"CAP_AUDIT_WRITE",
+				"CAP_KILL",
+				"CAP_NET_BIND_SERVICE"
+			]
+		},
+		"rlimits": [
+			{
+				"type": "RLIMIT_NOFILE",
+				"hard": 1024,
+				"soft": 1024
+			}
+		],
+		"noNewPrivileges": true
+	},
+	"root": {
+		"path": "rootfs",
+		"readonly": true
+	},
+	"hostname": "runc",
+	"mounts": [
+		{
+			"destination": "/proc",
+			"type": "proc",
+			"source": "proc"
+		},
+		{
+			"destination": "/dev",
+			"type": "tmpfs",
+			"source": "tmpfs",
+			"options": [
+				"nosuid",
+				"strictatime",
+				"mode=755",
+				"size=65536k"
+			]
+		},
+		{
+			"destination": "/dev/pts",
+			"type": "devpts",
+			"source": "devpts",
+			"options": [
+				"nosuid",
+				"noexec",
+				"newinstance",
+				"ptmxmode=0666",
+				"mode=0620",
+				"gid=5"
+			]
+		},
+		{
+			"destination": "/dev/shm",
+			"type": "tmpfs",
+			"source": "shm",
+			"options": [
+				"nosuid",
+				"noexec",
+				"nodev",
+				"mode=1777",
+				"size=65536k"
+			]
+		},
+		{
+			"destination": "/dev/mqueue",
+			"type": "mqueue",
+			"source": "mqueue",
+			"options": [
+				"nosuid",
+				"noexec",
+				"nodev"
+			]
+		},
+		{
+			"destination": "/sys",
+			"type": "sysfs",
+			"source": "sysfs",
+			"options": [
+				"nosuid",
+				"noexec",
+				"nodev",
+				"ro"
+			]
+		},
+		{
+			"destination": "/sys/fs/cgroup",
+			"type": "cgroup",
+			"source": "cgroup",
+			"options": [
+				"nosuid",
+				"noexec",
+				"nodev",
+				"relatime",
+				"ro"
+			]
+		}
+	],
+	"linux": {
+		"resources": {
+			"devices": [
+				{
+					"allow": false,
+					"access": "rwm"
+				}
+			]
+		},
+		"namespaces": [
+			{
+				"type": "pid"
+			},
+			{
+				"type": "network"
+			},
+			{
+				"type": "ipc"
+			},
+			{
+				"type": "uts"
+			},
+			{
+				"type": "mount"
+			}
+		],
+		"maskedPaths": [
+			"/proc/acpi",
+			"/proc/asound",
+			"/proc/kcore",
+			"/proc/keys",
+			"/proc/latency_stats",
+			"/proc/timer_list",
+			"/proc/timer_stats",
+			"/proc/sched_debug",
+			"/sys/firmware",
+			"/proc/scsi"
+		],
+		"readonlyPaths": [
+			"/proc/bus",
+			"/proc/fs",
+			"/proc/irq",
+			"/proc/sys",
+			"/proc/sysrq-trigger"
+		]
+	}
+}`
 )
 
 type RuntimeConfigOptions struct {
@@ -154,3 +349,34 @@ func IsInGitHubActions() bool {
 	// https://docs.github.com/en/actions/reference/environment-variables#default-environment-variables
 	return os.Getenv("GITHUB_ACTIONS") == "true"
 }
+
+func SetupOCIConfigFile(t *testing.T) (rootPath string, bundlePath, ociConfigFile string) {
+	assert := assert.New(t)
+
+	tmpdir, err := ioutil.TempDir("", "katatest-")
+	assert.NoError(err)
+
+	bundlePath = filepath.Join(tmpdir, "bundle")
+	err = os.MkdirAll(bundlePath, testDirMode)
+	assert.NoError(err)
+
+	ociConfigFile = filepath.Join(bundlePath, "config.json")
+	err = ioutil.WriteFile(ociConfigFile, []byte(busyboxConfigJson), testFileMode)
+	assert.NoError(err)
+
+	return tmpdir, bundlePath, ociConfigFile
+}
+
+// WriteOCIConfigFile using spec to update OCI config file by path configPath
+func WriteOCIConfigFile(spec specs.Spec, configPath string) error {
+	if configPath == "" {
+		return errors.New("BUG: need config file path")
+	}
+
+	bytes, err := json.MarshalIndent(spec, "", "\t")
+	if err != nil {
+		return err
+	}
+
+	return ioutil.WriteFile(configPath, bytes, testFileMode)
+}