packer/test/plugin_test.go

package test

import (
	"fmt"
	"io"
	"os"
	"os/exec"
	"path/filepath"
	"runtime"
	"sync"
	"testing"

	"github.com/hashicorp/go-version"
)

var compiledPlugins = struct {
	pluginVersions map[string]string
	RWMutex        sync.RWMutex
}{
	pluginVersions: map[string]string{},
}

func StorePluginVersion(pluginVersion, path string) {
	compiledPlugins.RWMutex.Lock()
	defer compiledPlugins.RWMutex.Unlock()
	compiledPlugins.pluginVersions[pluginVersion] = path
}

func LoadPluginVersion(pluginVersion string) (string, bool) {
	compiledPlugins.RWMutex.RLock()
	defer compiledPlugins.RWMutex.RUnlock()

	path, ok := compiledPlugins.pluginVersions[pluginVersion]
	return path, ok
}

var tempPluginBinaryPath = struct {
	path string
	once sync.Once
}{}

// PluginBinaryDir returns the path to the directory where temporary binaries will be compiled
func PluginBinaryDir() string {
	tempPluginBinaryPath.once.Do(func() {
		tempDir, err := os.MkdirTemp("", "packer-core-acc-test-")
		if err != nil {
			panic(fmt.Sprintf("failed to create temporary directory for compiled plugins: %s", err))
		}

		tempPluginBinaryPath.path = tempDir
	})

	return tempPluginBinaryPath.path
}

type PluginBuildConfig struct {
	version *version.Version
}

func NewPluginBuildConfig(versionStr string) *PluginBuildConfig {
	return &PluginBuildConfig{
		version.Must(version.NewVersion(versionStr)),
	}
}

// Version is the core version string of the test plugin.
//
// If the version isn't set, it'll default to 1.0.0
func (pc PluginBuildConfig) Version() string {
	return pc.version.Core().String()
}

func (pc PluginBuildConfig) PreRelease() string {
	return pc.version.Prerelease()
}

func (pc PluginBuildConfig) Metadata() string {
	return pc.version.Metadata()
}

// LDFlags compiles the ldflags for the plugin to compile based on the information provided.
func (pc PluginBuildConfig) LDFlags() string {
	pluginPackage := "github.com/hashicorp/packer-plugin-tester"

	ldflagsArg := fmt.Sprintf("-X %s/version.Version=%s", pluginPackage, pc.Version())
	if pc.PreRelease() != "" {
		ldflagsArg = fmt.Sprintf("%s -X %s/version.VersionPrerelease=%s", ldflagsArg, pluginPackage, pc.PreRelease())
	}
	if pc.Metadata() != "" {
		ldflagsArg = fmt.Sprintf("%s -X %s/version.VersionMetadata=%s", ldflagsArg, pluginPackage, pc.Metadata())
	}

	return ldflagsArg
}

// BinaryName is the raw name of the plugin binary to produce
//
// It's expected to be in the "mini-plugin_<version>[-<prerelease>][+<metadata>]" format
func (pc PluginBuildConfig) BinaryName() string {
	retStr := fmt.Sprintf("mini-plugin_%s", pc.Version())
	if pc.PreRelease() != "" {
		retStr = fmt.Sprintf("%s-%s", retStr, pc.PreRelease())
	}
	if pc.Metadata() != "" {
		retStr = fmt.Sprintf("%s+%s", retStr, pc.Metadata())
	}

	return retStr
}

// BuildSimplePlugin creates a plugin that essentially does nothing.
//
// The plugin's code is contained in a subdirectory of this, and lets us
// change the attributes of the plugin binary itself, like the SDK version,
// the plugin's version, etc.
//
// The plugin is functional, and can be used to run builds with.
// There won't be anything substantial created though, its goal is only
// to validate the core functionality of Packer.
//
// The path to the plugin is returned, it won't be removed automatically
// though, deletion is the caller's responsibility.
func BuildSimplePlugin(config *PluginBuildConfig, t *testing.T) {
	t.Logf("Building plugin in version %v", config.version)

	testDir, err := currentDir()
	if err != nil {
		t.Fatalf("failed to compile plugin binary: %s", err)
	}

	miniPluginDir := filepath.Join(testDir, "mini_plugin")
	outBin := filepath.Join(PluginBinaryDir(), config.BinaryName())

	compileCommand := exec.Command("go", "build", "-C", miniPluginDir, "-o", outBin, "-ldflags", config.LDFlags(), ".")
	logs, err := compileCommand.CombinedOutput()
	if err != nil {
		t.Fatalf("failed to compile plugin binary: %s\ncompiler logs: %s", err, logs)
	}

	StorePluginVersion(config.version.String(), outBin)
}

// currentDir returns the directory in which the current file is located.
//
// Since we're in tests it's reliable as they're supposed to run on the same
// machine the binary's compiled from, but goes to say it's not meant for use
// in distributed binaries.
func currentDir() (string, error) {
	// pc uintptr, file string, line int, ok bool
	_, testDir, _, ok := runtime.Caller(0)
	if !ok {
		return "", fmt.Errorf("couldn't get the location of the test suite file")
	}

	return filepath.Dir(testDir), nil
}

// MakePluginDir installs a list of plugins into a temporary directory and returns its path
//
// This can be set in the environment for a test through a function like t.SetEnv(), so
// packer will be able to use that directory for running its functions.
//
// Deletion of the directory is the caller's responsibility.
func (ts *PackerTestSuite) MakePluginDir(t *testing.T, pluginVersions ...string) (pluginTempDir string, cleanup func()) {
	var err error

	defer func() {
		if err != nil {
			if pluginTempDir != "" {
				os.RemoveAll(pluginTempDir)
			}
			t.Fatalf("failed to prepare temporary plugin directory %q: %s", pluginTempDir, err)
		}
	}()

	pluginTempDir, err = os.MkdirTemp("", "packer-plugin-dir-temp-")
	if err != nil {
		return
	}

	for _, pluginVersion := range pluginVersions {
		path, _ := LoadPluginVersion(pluginVersion)
		cmd := ts.PackerCommand().SetArgs("plugins", "install", "--path", path, "github.com/hashicorp/tester").AddEnv("PACKER_PLUGIN_PATH", pluginTempDir)
		cmd.Assert(t, MustSucceed{})
		out, stderr, cmdErr := cmd.Run(t)
		if cmdErr != nil {
			err = fmt.Errorf("failed to install tester plugin version %q: %s\nCommand stdout: %s\nCommand stderr: %s", pluginVersion, err, out, stderr)
			return
		}
	}

	return pluginTempDir, func() {
		err := os.RemoveAll(pluginTempDir)
		if err != nil {
			t.Logf("failed to remove temporary plugin directory %q: %s. This may need manual intervention.", pluginTempDir, err)
		}
	}
}