vpython/venv/venv_resources_test.go - infra/luci/luci-go - Git at Google

 // Copyright 2017 The LUCI 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 venv

 import (
 	"archive/zip"
 	"context"
 	"crypto/sha256"
 	"encoding/hex"
 	"hash"
 	"io"
 	"io/ioutil"
 	"net/http"
 	"os"
 	"path/filepath"
 	"testing"
 	"time"

 	"github.com/danjacques/gofslock/fslock"

 	"go.chromium.org/luci/cipd/client/cipd"
 	"go.chromium.org/luci/cipd/common"
 	"go.chromium.org/luci/common/errors"
 	"go.chromium.org/luci/common/system/environ"
 	"go.chromium.org/luci/common/system/filesystem"
 	"go.chromium.org/luci/hardcoded/chromeinfra"
 	"go.chromium.org/luci/vpython/api/vpython"
 	"go.chromium.org/luci/vpython/python"
 	"go.chromium.org/luci/vpython/wheel"
 )

 const testDataDir = "test_data"

 // remoteFiles is the set of remote files to acquire.
 var remoteFiles = []struct {
 	// install installs this remote file into the test environment.
 	install func(te *testingLoader, path string)

 	// name is the name of the file.
 	name string
 	// contentHash is the SHA256 has of the content.
 	contentHash string

 	// cipdPackage, if not empty, is the name of the CIPD package that contains
 	// this file.
 	cipdPackage string
 	// cipdVersion is the version string of the CIPD package.
 	cipdVersion string

 	// urls, if not empty, is a set of remote URLs where this file can be
 	// downloaded from.
 	urls []string
 }{
 	{
 		install:     func(tl *testingLoader, path string) { tl.virtualEnvZIP = path },
 		name:        "virtualenv-15.1.0.zip",
 		contentHash: "f7682a57c98a10d32474b4c1df75478dea9a0802c140335c0269a6ec3af46201",
 		cipdPackage: "infra/test-data/vpython/virtualenv",
 		cipdVersion: "version:15.1.0",
 		urls: []string{
 			"https://github.com/pypa/virtualenv/archive/15.1.0.zip",
 		},
 	},
 }

 // testingLoader is a map of a CIPD package name to the root directory
 // that it should be loaded from.
 type testingLoader struct {
 	PackageLoader

 	cacheDir string

 	virtualEnvZIP string

 	pantsWheelPath string
 	shirtWheelPath string
 }

 // loadTestEnvironment sets up the test environment for the VirtualEnv tests.
 //
 // This environment includes the acquisition and construction of binary data
 // that will be used to perform the VirtualEnv test suite, namely:
 //
 //	- Building test wheel files from source.
 //	- Downloading the testing VirtualEnv package.
 //
 // This online setup is preferred to actually checking these binary files into
 // Git, as it offers more versatility and doesn't clutter Git with binary junk.
 //
 // To optimize repeated test re-executions, withTestEnvironment will also cache
 // the downloaded artifacts in a cache directory. All artifacts will be verified
 // by their SHA256 hashes, which will be baked into the source here.
 func loadTestEnvironment(ctx context.Context, t *testing.T) (*testingLoader, error) {
 	wd, err := os.Getwd()
 	if err != nil {
 		return nil, errors.Annotate(err, "failed to get working directory").Err()
 	}

 	cacheDir := filepath.Join(wd, ".venv_test_cache")
 	if err := filesystem.MakeDirs(cacheDir); err != nil {
 		return nil, errors.Annotate(err, "failed to create cache dir").Err()
 	}

 	tl := testingLoader{
 		cacheDir: cacheDir,
 	}
 	return &tl, tl.withCacheLock(t, func() error {
 		return tl.ensureRemoteFilesLocked(ctx, t)
 	})
 }

 func (tl *testingLoader) withCacheLock(t *testing.T, fn func() error) error {
 	lockPath := filepath.Join(tl.cacheDir, ".lock")
 	blocker := func() error {
 		t.Logf("Cache [%s] is currently locked; sleeping...", lockPath)
 		time.Sleep(1 * time.Second)
 		return nil
 	}
 	return fslock.WithBlocking(lockPath, blocker, func() error {
 		return fn()
 	})
 }

 func (tl *testingLoader) ensureWheels(ctx context.Context, t *testing.T, py *python.Interpreter, tdir string) error {
 	var err error
 	if tl.pantsWheelPath, err = tl.buildWheelLocked(t, py, "pants-1.2-py2.py3-none-any.whl", tdir); err != nil {
 		return err
 	}
 	if tl.shirtWheelPath, err = tl.buildWheelLocked(t, py, "shirt-3.14-py2.py3-none-any.whl", tdir); err != nil {
 		return err
 	}
 	return nil
 }

 func (tl *testingLoader) Resolve(c context.Context, e *vpython.Environment) error {

 	e.Spec.Virtualenv.Version = "resolved"
 	for _, wheel := range e.Spec.Wheel {
 		wheel.Version = "resolved"
 	}
 	return nil
 }

 func (tl *testingLoader) Ensure(c context.Context, root string, packages []*vpython.Spec_Package) error {
 	for _, pkg := range packages {
 		if err := tl.installPackage(pkg.Name, root); err != nil {
 			return err
 		}
 	}
 	return nil
 }

 func (tl *testingLoader) installPackage(name, root string) error {
 	switch name {
 	case "foo/bar/virtualenv":
 		return unzip(tl.virtualEnvZIP, root)
 	case "foo/bar/shirt":
 		return copyFileIntoDir(tl.shirtWheelPath, root)
 	case "foo/bar/pants":
 		return copyFileIntoDir(tl.pantsWheelPath, root)

 	default:
 		return errors.Reason("don't know how to install %q", name).Err()
 	}
 }

 func (tl *testingLoader) buildWheelLocked(t *testing.T, py *python.Interpreter, name, outDir string) (string, error) {
 	ctx := context.Background()
 	w, err := wheel.ParseName(name)
 	if err != nil {
 		return "", errors.Annotate(err, "failed to parse wheel name %q", name).Err()
 	}

 	outWheelPath := filepath.Join(outDir, w.String())
 	switch _, err := os.Stat(outWheelPath); {
 	case err == nil:
 		t.Logf("Using cached wheel for %q: %s", name, outWheelPath)
 		return outWheelPath, nil

 	case os.IsNotExist(err):
 		// Will build a new wheel.
 		break

 	default:
 		return "", errors.Annotate(err, "failed to stat wheel path [%s]", outWheelPath).Err()
 	}

 	srcDir := filepath.Join(testDataDir, w.Distribution+".src")

 	// Create a bootstrap wheel-generating VirtualEnv!
 	cfg := Config{
 		MaxHashLen: 1, // Only going to be 1 environment.
 		BaseDir:    filepath.Join(outDir, ".env"),
 		SetupEnv:   environ.System(),
 		Python:     []string{py.Python},
 		Package: vpython.Spec_Package{
 			Name:    "foo/bar/virtualenv",
 			Version: "whatever",
 		},
 		Loader: tl,
 		Spec:   &vpython.Spec{},

 		// Testing parameters for this bootstrap wheel-building environment.
 		testLeaveReadWrite: true,
 	}

 	// Build the wheel in a temporary directory, then copy it into outDir. This
 	// will stop wheel builds from stepping on each other or inheriting each
 	// others' state accidentally.
 	tdir, err := ioutil.TempDir(t.TempDir(), "vpython_venv_wheel")
 	if err != nil {
 		return "", errors.Annotate(err, "failed to create tempdir").Err()
 	}

 	buildDir := filepath.Join(tdir, "build")
 	if err := filesystem.MakeDirs(buildDir); err != nil {
 		return "", err
 	}

 	distDir := filepath.Join(tdir, "dist")
 	if err := filesystem.MakeDirs(distDir); err != nil {
 		return "", err
 	}

 	// Use an empty bootstrap VirtualEnv to build the wheel. This guarantees
 	// that we actually have "setuptools" and "wheel" packages, which are
 	// required for building wheels, and not necessarily present in their
 	// expected forms on all systems.
 	err = With(ctx, cfg, func(ctx context.Context, env *Env) error {
 		cmd := env.Interpreter().MkIsolatedCommand(ctx,
 			python.ScriptTarget{Path: "setup.py"},
 			"--no-user-cfg",
 			"bdist_wheel",
 			"--bdist-dir", buildDir,
 			"--dist-dir", distDir)
 		defer cmd.Cleanup()
 		cmd.Dir = srcDir
 		if err := cmd.Run(); err != nil {
 			return errors.Annotate(err, "failed to build wheel").Err()
 		}
 		return nil
 	})
 	if err != nil {
 		return "", errors.Annotate(err, "failed to build wheel").Err()
 	}

 	// Assert that the expected wheel file was generated, and copy it into
 	// outDir.
 	wheelPath := filepath.Join(distDir, w.String())
 	if _, err := os.Stat(wheelPath); err != nil {
 		return "", errors.Annotate(err, "failed to generate wheel").Err()
 	}
 	if err := copyFileIntoDir(wheelPath, outDir); err != nil {
 		return "", errors.Annotate(err, "failed to install wheel").Err()
 	}

 	t.Logf("Generated wheel file %q: %s", name, outWheelPath)
 	return outWheelPath, nil
 }

 func (tl *testingLoader) ensureRemoteFilesLocked(ctx context.Context, t *testing.T) error {
 MainLoop:
 	for _, rf := range remoteFiles {
 		cachePath := filepath.Join(tl.cacheDir, rf.name)

 		// Check if the remote file is already cached.
 		err := getCachedFileLocked(t, cachePath, rf.contentHash)
 		if err == nil {
 			t.Logf("Remote file [%s] is already cached: [%s]", rf.name, cachePath)
 			rf.install(tl, cachePath)
 			continue MainLoop
 		}
 		t.Logf("Remote file [%s] is not cached: %s", rf.name, err)

 		// Download from CIPD.
 		if rf.cipdPackage != "" {
 			err := cacheFromCIPDLocked(ctx, t, cachePath, rf.name, rf.contentHash, rf.cipdPackage, rf.cipdVersion)
 			if err == nil {
 				t.Logf("Cached remote file [%s] from CIPD source: [%s]", rf.name, cachePath)
 				rf.install(tl, cachePath)
 				continue MainLoop
 			}
 			t.Logf("Failed to load from CIPD package %q @%q: %s", rf.cipdPackage, rf.cipdVersion, err)
 		}

 		// Download from URL.
 		for _, url := range rf.urls {
 			err := cacheFromURLLocked(t, cachePath, rf.contentHash, url)
 			if err == nil {
 				t.Logf("Cached remote file [%s] from URL [%s]: [%s]", rf.name, url, cachePath)
 				rf.install(tl, cachePath)
 				continue MainLoop
 			}
 			t.Logf("Failed to load from URL %q: %s", url, err)
 		}

 		return errors.Reason("failed to acquire remote file %q", rf.name).Err()
 	}

 	return nil
 }

 func getCachedFileLocked(t *testing.T, cachePath, hash string) error {
 	return validateHash(t, cachePath, hash, true)
 }

 func validateHash(t *testing.T, path, hash string, deleteIfInvalid bool) error {
 	fd, err := os.Open(path)
 	if err != nil {
 		return errors.Annotate(err, "failed to open file").Err()
 	}
 	defer fd.Close()

 	h := sha256.New()
 	if _, err := io.Copy(h, fd); err != nil {
 		return errors.Annotate(err, "failed to hash file").Err()
 	}

 	if err := hashesEqual(h, hash); err != nil {
 		t.Logf("File [%s] has invalid hash: %s", path, err)

 		if deleteIfInvalid {
 			if err := os.Remove(path); err != nil {
 				t.Logf("Failed to delete invalid hash file [%s]: %s", path, err)
 			}
 		}
 		return err
 	}

 	return nil
 }

 func hashesEqual(h hash.Hash, expected string) error {
 	if v := hex.EncodeToString(h.Sum(nil)); v != expected {
 		return errors.Reason("hash %q doesn't match expected %q", v, expected).Err()
 	}
 	return nil
 }

 var testCIPDClientOptions = cipd.ClientOptions{
 	ServiceURL: chromeinfra.CIPDServiceURL,
 	UserAgent:  "vpython venv tests",
 }

 func cacheFromCIPDLocked(ctx context.Context, t *testing.T, cachePath, name, hash, pkg, version string) error {
 	tdir, err := ioutil.TempDir(t.TempDir(), "vpython_venv_cipd")
 	if err != nil {
 		return errors.Annotate(err, "failed to create tempdir").Err()
 	}

 	opts := testCIPDClientOptions
 	opts.Root = tdir

 	client, err := cipd.NewClient(opts)
 	if err != nil {
 		return errors.Annotate(err, "failed to create CIPD client").Err()
 	}
 	defer client.Close(ctx)

 	pin, err := client.ResolveVersion(ctx, pkg, version)
 	if err != nil {
 		return errors.Annotate(err, "failed to resolve CIPD version for %s @%s", pkg, version).Err()
 	}

 	_, err = client.EnsurePackages(ctx, common.PinSliceBySubdir{"": {pin}}, nil)
 	if err != nil {
 		return errors.Annotate(err, "failed to fetch/deploy CIPD package").Err()
 	}

 	path := filepath.Join(opts.Root, name)
 	if err := validateHash(t, path, hash, false); err != nil {
 		// Do not export the invalid path.
 		return err
 	}

 	if err := copyFile(path, cachePath, nil); err != nil {
 		return errors.Annotate(err, "failed to install CIPD package file").Err()
 	}

 	return nil
 }

 func cacheFromURLLocked(t *testing.T, cachePath, hash, url string) (err error) {
 	resp, err := http.Get(url)
 	if err != nil {
 		t.Logf("Failed to GET file from URL [%s]: %s", url, err)
 	}
 	defer resp.Body.Close()

 	fd, err := os.Create(cachePath)
 	if err != nil {
 		t.Logf("Failed to create output file [%s]: %s", cachePath, err)
 	}
 	defer func() {
 		if closeErr := fd.Close(); closeErr != nil && err == nil {
 			err = errors.Annotate(closeErr, "failed to close file").Err()
 		}
 	}()

 	h := sha256.New()
 	tr := io.TeeReader(resp.Body, h)
 	if _, err := io.Copy(fd, tr); err != nil {
 		return errors.Annotate(err, "failed to download").Err()
 	}

 	if err = hashesEqual(h, hash); err != nil {
 		return
 	}
 	return nil
 }

 func unzip(src, dst string) error {
 	fd, err := zip.OpenReader(src)
 	if err != nil {
 		return errors.Annotate(err, "failed to open ZIP reader").Err()
 	}
 	defer fd.Close()

 	for _, f := range fd.File {
 		path := filepath.Join(dst, filepath.FromSlash(f.Name))
 		fi := f.FileInfo()

 		// Unzip this entry.
 		if fi.IsDir() {
 			if err := os.MkdirAll(path, 0755); err != nil {
 				return errors.Annotate(err, "failed to mkdir").Err()
 			}
 		} else {
 			if err := copyFileOpener(f.Open, path, fi); err != nil {
 				return err
 			}
 		}
 	}
 	return nil
 }

 func copyFileIntoDir(src, dstDir string) error {
 	return copyFile(src, filepath.Join(dstDir, filepath.Base(src)), nil)
 }

 func copyFile(src, dst string, fi os.FileInfo) error {
 	opener := func() (io.ReadCloser, error) { return os.Open(src) }
 	return copyFileOpener(opener, dst, fi)
 }

 func copyFileOpener(opener func() (io.ReadCloser, error), dst string, fi os.FileInfo) (err error) {
 	sfd, err := opener()
 	if err != nil {
 		return errors.Annotate(err, "failed to open source").Err()
 	}
 	defer sfd.Close()

 	dfd, err := os.Create(dst)
 	if err != nil {
 		return errors.Annotate(err, "failed to create destination").Err()
 	}
 	defer func() {
 		if closeErr := dfd.Close(); closeErr != nil && err == nil {
 			err = errors.Annotate(closeErr, "failed to close destination").Err()
 		}
 	}()

 	if _, err := io.Copy(dfd, sfd); err != nil {
 		return errors.Annotate(err, "failed to copy file").Err()
 	}
 	if fi != nil {
 		if err := os.Chmod(dst, fi.Mode()); err != nil {
 			return errors.Annotate(err, "failed to chmod").Err()
 		}
 	}
 	return nil
 }
	// Copyright 2017 The LUCI 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 venv

	import (
	"archive/zip"
	"context"
	"crypto/sha256"
	"encoding/hex"
	"hash"
	"io"
	"io/ioutil"
	"net/http"
	"os"
	"path/filepath"
	"testing"
	"time"

	"github.com/danjacques/gofslock/fslock"

	"go.chromium.org/luci/cipd/client/cipd"
	"go.chromium.org/luci/cipd/common"
	"go.chromium.org/luci/common/errors"
	"go.chromium.org/luci/common/system/environ"
	"go.chromium.org/luci/common/system/filesystem"
	"go.chromium.org/luci/hardcoded/chromeinfra"
	"go.chromium.org/luci/vpython/api/vpython"
	"go.chromium.org/luci/vpython/python"
	"go.chromium.org/luci/vpython/wheel"
	)

	const testDataDir = "test_data"

	// remoteFiles is the set of remote files to acquire.
	var remoteFiles = []struct {
	// install installs this remote file into the test environment.
	install func(te *testingLoader, path string)

	// name is the name of the file.
	name string
	// contentHash is the SHA256 has of the content.
	contentHash string

	// cipdPackage, if not empty, is the name of the CIPD package that contains
	// this file.
	cipdPackage string
	// cipdVersion is the version string of the CIPD package.
	cipdVersion string

	// urls, if not empty, is a set of remote URLs where this file can be
	// downloaded from.
	urls []string
	}{
	{
	install: func(tl *testingLoader, path string) { tl.virtualEnvZIP = path },
	name: "virtualenv-15.1.0.zip",
	contentHash: "f7682a57c98a10d32474b4c1df75478dea9a0802c140335c0269a6ec3af46201",
	cipdPackage: "infra/test-data/vpython/virtualenv",
	cipdVersion: "version:15.1.0",
	urls: []string{
	"https://github.com/pypa/virtualenv/archive/15.1.0.zip",
	},
	},
	}

	// testingLoader is a map of a CIPD package name to the root directory
	// that it should be loaded from.
	type testingLoader struct {
	PackageLoader

	cacheDir string

	virtualEnvZIP string

	pantsWheelPath string
	shirtWheelPath string
	}

	// loadTestEnvironment sets up the test environment for the VirtualEnv tests.
	//
	// This environment includes the acquisition and construction of binary data
	// that will be used to perform the VirtualEnv test suite, namely:
	//
	// - Building test wheel files from source.
	// - Downloading the testing VirtualEnv package.
	//
	// This online setup is preferred to actually checking these binary files into
	// Git, as it offers more versatility and doesn't clutter Git with binary junk.
	//
	// To optimize repeated test re-executions, withTestEnvironment will also cache
	// the downloaded artifacts in a cache directory. All artifacts will be verified
	// by their SHA256 hashes, which will be baked into the source here.
	func loadTestEnvironment(ctx context.Context, t testing.T) (testingLoader, error) {
	wd, err := os.Getwd()
	if err != nil {
	return nil, errors.Annotate(err, "failed to get working directory").Err()
	}

	cacheDir := filepath.Join(wd, ".venv_test_cache")
	if err := filesystem.MakeDirs(cacheDir); err != nil {
	return nil, errors.Annotate(err, "failed to create cache dir").Err()
	}

	tl := testingLoader{
	cacheDir: cacheDir,
	}
	return &tl, tl.withCacheLock(t, func() error {
	return tl.ensureRemoteFilesLocked(ctx, t)
	})
	}

	func (tl testingLoader) withCacheLock(t testing.T, fn func() error) error {
	lockPath := filepath.Join(tl.cacheDir, ".lock")
	blocker := func() error {
	t.Logf("Cache [%s] is currently locked; sleeping...", lockPath)
	time.Sleep(1 * time.Second)
	return nil
	}
	return fslock.WithBlocking(lockPath, blocker, func() error {
	return fn()
	})
	}

	func (tl testingLoader) ensureWheels(ctx context.Context, t testing.T, py *python.Interpreter, tdir string) error {
	var err error
	if tl.pantsWheelPath, err = tl.buildWheelLocked(t, py, "pants-1.2-py2.py3-none-any.whl", tdir); err != nil {
	return err
	}
	if tl.shirtWheelPath, err = tl.buildWheelLocked(t, py, "shirt-3.14-py2.py3-none-any.whl", tdir); err != nil {
	return err
	}
	return nil
	}

	func (tl testingLoader) Resolve(c context.Context, e vpython.Environment) error {

	e.Spec.Virtualenv.Version = "resolved"
	for _, wheel := range e.Spec.Wheel {
	wheel.Version = "resolved"
	}
	return nil
	}

	func (tl testingLoader) Ensure(c context.Context, root string, packages []vpython.Spec_Package) error {
	for _, pkg := range packages {
	if err := tl.installPackage(pkg.Name, root); err != nil {
	return err
	}
	}
	return nil
	}

	func (tl *testingLoader) installPackage(name, root string) error {
	switch name {
	case "foo/bar/virtualenv":
	return unzip(tl.virtualEnvZIP, root)
	case "foo/bar/shirt":
	return copyFileIntoDir(tl.shirtWheelPath, root)
	case "foo/bar/pants":
	return copyFileIntoDir(tl.pantsWheelPath, root)

	default:
	return errors.Reason("don't know how to install %q", name).Err()
	}
	}

	func (tl testingLoader) buildWheelLocked(t testing.T, py *python.Interpreter, name, outDir string) (string, error) {
	ctx := context.Background()
	w, err := wheel.ParseName(name)
	if err != nil {
	return "", errors.Annotate(err, "failed to parse wheel name %q", name).Err()
	}

	outWheelPath := filepath.Join(outDir, w.String())
	switch _, err := os.Stat(outWheelPath); {
	case err == nil:
	t.Logf("Using cached wheel for %q: %s", name, outWheelPath)
	return outWheelPath, nil

	case os.IsNotExist(err):
	// Will build a new wheel.
	break

	default:
	return "", errors.Annotate(err, "failed to stat wheel path [%s]", outWheelPath).Err()
	}

	srcDir := filepath.Join(testDataDir, w.Distribution+".src")

	// Create a bootstrap wheel-generating VirtualEnv!
	cfg := Config{
	MaxHashLen: 1, // Only going to be 1 environment.
	BaseDir: filepath.Join(outDir, ".env"),
	SetupEnv: environ.System(),
	Python: []string{py.Python},
	Package: vpython.Spec_Package{
	Name: "foo/bar/virtualenv",
	Version: "whatever",
	},
	Loader: tl,
	Spec: &vpython.Spec{},

	// Testing parameters for this bootstrap wheel-building environment.
	testLeaveReadWrite: true,
	}

	// Build the wheel in a temporary directory, then copy it into outDir. This
	// will stop wheel builds from stepping on each other or inheriting each
	// others' state accidentally.
	tdir, err := ioutil.TempDir(t.TempDir(), "vpython_venv_wheel")
	if err != nil {
	return "", errors.Annotate(err, "failed to create tempdir").Err()
	}

	buildDir := filepath.Join(tdir, "build")
	if err := filesystem.MakeDirs(buildDir); err != nil {
	return "", err
	}

	distDir := filepath.Join(tdir, "dist")
	if err := filesystem.MakeDirs(distDir); err != nil {
	return "", err
	}

	// Use an empty bootstrap VirtualEnv to build the wheel. This guarantees
	// that we actually have "setuptools" and "wheel" packages, which are
	// required for building wheels, and not necessarily present in their
	// expected forms on all systems.
	err = With(ctx, cfg, func(ctx context.Context, env *Env) error {
	cmd := env.Interpreter().MkIsolatedCommand(ctx,
	python.ScriptTarget{Path: "setup.py"},
	"--no-user-cfg",
	"bdist_wheel",
	"--bdist-dir", buildDir,
	"--dist-dir", distDir)
	defer cmd.Cleanup()
	cmd.Dir = srcDir
	if err := cmd.Run(); err != nil {
	return errors.Annotate(err, "failed to build wheel").Err()
	}
	return nil
	})
	if err != nil {
	return "", errors.Annotate(err, "failed to build wheel").Err()
	}

	// Assert that the expected wheel file was generated, and copy it into
	// outDir.
	wheelPath := filepath.Join(distDir, w.String())
	if _, err := os.Stat(wheelPath); err != nil {
	return "", errors.Annotate(err, "failed to generate wheel").Err()
	}
	if err := copyFileIntoDir(wheelPath, outDir); err != nil {
	return "", errors.Annotate(err, "failed to install wheel").Err()
	}

	t.Logf("Generated wheel file %q: %s", name, outWheelPath)
	return outWheelPath, nil
	}

	func (tl testingLoader) ensureRemoteFilesLocked(ctx context.Context, t testing.T) error {
	MainLoop:
	for _, rf := range remoteFiles {
	cachePath := filepath.Join(tl.cacheDir, rf.name)

	// Check if the remote file is already cached.
	err := getCachedFileLocked(t, cachePath, rf.contentHash)
	if err == nil {
	t.Logf("Remote file [%s] is already cached: [%s]", rf.name, cachePath)
	rf.install(tl, cachePath)
	continue MainLoop
	}
	t.Logf("Remote file [%s] is not cached: %s", rf.name, err)

	// Download from CIPD.
	if rf.cipdPackage != "" {
	err := cacheFromCIPDLocked(ctx, t, cachePath, rf.name, rf.contentHash, rf.cipdPackage, rf.cipdVersion)
	if err == nil {
	t.Logf("Cached remote file [%s] from CIPD source: [%s]", rf.name, cachePath)
	rf.install(tl, cachePath)
	continue MainLoop
	}
	t.Logf("Failed to load from CIPD package %q @%q: %s", rf.cipdPackage, rf.cipdVersion, err)
	}

	// Download from URL.
	for _, url := range rf.urls {
	err := cacheFromURLLocked(t, cachePath, rf.contentHash, url)
	if err == nil {
	t.Logf("Cached remote file [%s] from URL [%s]: [%s]", rf.name, url, cachePath)
	rf.install(tl, cachePath)
	continue MainLoop
	}
	t.Logf("Failed to load from URL %q: %s", url, err)
	}

	return errors.Reason("failed to acquire remote file %q", rf.name).Err()
	}

	return nil
	}

	func getCachedFileLocked(t *testing.T, cachePath, hash string) error {
	return validateHash(t, cachePath, hash, true)
	}

	func validateHash(t *testing.T, path, hash string, deleteIfInvalid bool) error {
	fd, err := os.Open(path)
	if err != nil {
	return errors.Annotate(err, "failed to open file").Err()
	}
	defer fd.Close()

	h := sha256.New()
	if _, err := io.Copy(h, fd); err != nil {
	return errors.Annotate(err, "failed to hash file").Err()
	}

	if err := hashesEqual(h, hash); err != nil {
	t.Logf("File [%s] has invalid hash: %s", path, err)

	if deleteIfInvalid {
	if err := os.Remove(path); err != nil {
	t.Logf("Failed to delete invalid hash file [%s]: %s", path, err)
	}
	}
	return err
	}

	return nil
	}

	func hashesEqual(h hash.Hash, expected string) error {
	if v := hex.EncodeToString(h.Sum(nil)); v != expected {
	return errors.Reason("hash %q doesn't match expected %q", v, expected).Err()
	}
	return nil
	}

	var testCIPDClientOptions = cipd.ClientOptions{
	ServiceURL: chromeinfra.CIPDServiceURL,
	UserAgent: "vpython venv tests",
	}

	func cacheFromCIPDLocked(ctx context.Context, t *testing.T, cachePath, name, hash, pkg, version string) error {
	tdir, err := ioutil.TempDir(t.TempDir(), "vpython_venv_cipd")
	if err != nil {
	return errors.Annotate(err, "failed to create tempdir").Err()
	}

	opts := testCIPDClientOptions
	opts.Root = tdir

	client, err := cipd.NewClient(opts)
	if err != nil {
	return errors.Annotate(err, "failed to create CIPD client").Err()
	}
	defer client.Close(ctx)

	pin, err := client.ResolveVersion(ctx, pkg, version)
	if err != nil {
	return errors.Annotate(err, "failed to resolve CIPD version for %s @%s", pkg, version).Err()
	}

	_, err = client.EnsurePackages(ctx, common.PinSliceBySubdir{"": {pin}}, nil)
	if err != nil {
	return errors.Annotate(err, "failed to fetch/deploy CIPD package").Err()
	}

	path := filepath.Join(opts.Root, name)
	if err := validateHash(t, path, hash, false); err != nil {
	// Do not export the invalid path.
	return err
	}

	if err := copyFile(path, cachePath, nil); err != nil {
	return errors.Annotate(err, "failed to install CIPD package file").Err()
	}

	return nil
	}

	func cacheFromURLLocked(t *testing.T, cachePath, hash, url string) (err error) {
	resp, err := http.Get(url)
	if err != nil {
	t.Logf("Failed to GET file from URL [%s]: %s", url, err)
	}
	defer resp.Body.Close()

	fd, err := os.Create(cachePath)
	if err != nil {
	t.Logf("Failed to create output file [%s]: %s", cachePath, err)
	}
	defer func() {
	if closeErr := fd.Close(); closeErr != nil && err == nil {
	err = errors.Annotate(closeErr, "failed to close file").Err()
	}
	}()

	h := sha256.New()
	tr := io.TeeReader(resp.Body, h)
	if _, err := io.Copy(fd, tr); err != nil {
	return errors.Annotate(err, "failed to download").Err()
	}

	if err = hashesEqual(h, hash); err != nil {
	return
	}
	return nil
	}

	func unzip(src, dst string) error {
	fd, err := zip.OpenReader(src)
	if err != nil {
	return errors.Annotate(err, "failed to open ZIP reader").Err()
	}
	defer fd.Close()

	for _, f := range fd.File {
	path := filepath.Join(dst, filepath.FromSlash(f.Name))
	fi := f.FileInfo()

	// Unzip this entry.
	if fi.IsDir() {
	if err := os.MkdirAll(path, 0755); err != nil {
	return errors.Annotate(err, "failed to mkdir").Err()
	}
	} else {
	if err := copyFileOpener(f.Open, path, fi); err != nil {
	return err
	}
	}
	}
	return nil
	}

	func copyFileIntoDir(src, dstDir string) error {
	return copyFile(src, filepath.Join(dstDir, filepath.Base(src)), nil)
	}

	func copyFile(src, dst string, fi os.FileInfo) error {
	opener := func() (io.ReadCloser, error) { return os.Open(src) }
	return copyFileOpener(opener, dst, fi)
	}

	func copyFileOpener(opener func() (io.ReadCloser, error), dst string, fi os.FileInfo) (err error) {
	sfd, err := opener()
	if err != nil {
	return errors.Annotate(err, "failed to open source").Err()
	}
	defer sfd.Close()

	dfd, err := os.Create(dst)
	if err != nil {
	return errors.Annotate(err, "failed to create destination").Err()
	}
	defer func() {
	if closeErr := dfd.Close(); closeErr != nil && err == nil {
	err = errors.Annotate(closeErr, "failed to close destination").Err()
	}
	}()

	if _, err := io.Copy(dfd, sfd); err != nil {
	return errors.Annotate(err, "failed to copy file").Err()
	}
	if fi != nil {
	if err := os.Chmod(dst, fi.Mode()); err != nil {
	return errors.Annotate(err, "failed to chmod").Err()
	}
	}
	return nil
	}