app/appengine/build.go - build - Git at Google

 // Copyright 2011 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.

 package main

 import (
 	"bytes"
 	"compress/gzip"
 	"context"
 	"errors"
 	"fmt"
 	"io"
 	"io/ioutil"
 	"math/rand"
 	pathpkg "path"
 	"strings"

 	"cloud.google.com/go/datastore"
 	"golang.org/x/build/dashboard"
 	"golang.org/x/build/internal/loghash"
 )

 const (
 	maxDatastoreStringLen = 500
 )

 func dsKey(kind, name string, parent *datastore.Key) *datastore.Key {
 	dk := datastore.NameKey(kind, name, parent)
 	dk.Namespace = "Git"
 	return dk
 }

 // A Package describes a package that is listed on the dashboard.
 type Package struct {
 	Name string // "Go", "arch", "net", ...
 	Path string // empty for the main Go tree, else "golang.org/x/foo"
 }

 func (p *Package) String() string {
 	return fmt.Sprintf("%s: %q", p.Path, p.Name)
 }

 func (p *Package) Key() *datastore.Key {
 	key := p.Path
 	if key == "" {
 		key = "go"
 	}
 	return dsKey("Package", key, nil)
 }

 // filterDatastoreError returns err, unless it's just about datastore
 // not being able to load an entity with old legacy struct fields into
 // the Commit type that has since removed those fields.
 func filterDatastoreError(err error) error {
 	return filterAppEngineError(err, func(err error) bool {
 		if em, ok := err.(*datastore.ErrFieldMismatch); ok {
 			switch em.FieldName {
 			case "NeedsBenchmarking", "TryPatch", "FailNotificationSent":
 				// Removed in CLs 208397 and 208324.
 				return true
 			case "PackagePath", "ParentHash", "Num", "User", "Desc", "Time", "Branch", "NextNum", "Kind":
 				// Removed in move to maintner in CL 208697.
 				return true
 			}
 		}
 		return false
 	})
 }

 // filterNoSuchEntity returns err, unless it's just about datastore
 // not being able to load an entity because it doesn't exist.
 func filterNoSuchEntity(err error) error {
 	return filterAppEngineError(err, func(err error) bool {
 		return err == datastore.ErrNoSuchEntity
 	})
 }

 // filterAppEngineError returns err, unless ignore(err) is true,
 // in which case it returns nil. If err is an datastore.MultiError,
 // it returns either nil (if all errors are ignored) or a deep copy
 // with the non-ignored errors.
 func filterAppEngineError(err error, ignore func(error) bool) error {
 	if err == nil || ignore(err) {
 		return nil
 	}
 	if me, ok := err.(datastore.MultiError); ok {
 		me2 := make(datastore.MultiError, 0, len(me))
 		for _, err := range me {
 			if e2 := filterAppEngineError(err, ignore); e2 != nil {
 				me2 = append(me2, e2)
 			}
 		}
 		if len(me2) == 0 {
 			return nil
 		}
 		return me2
 	}
 	return err
 }

 // getOrMakePackageInTx fetches a Package by path from the datastore,
 // creating it if necessary.
 func getOrMakePackageInTx(ctx context.Context, tx *datastore.Transaction, path string) (*Package, error) {
 	p := &Package{Path: path}
 	if path != "" {
 		p.Name = pathpkg.Base(path)
 	} else {
 		p.Name = "Go"
 	}
 	err := tx.Get(p.Key(), p)
 	err = filterDatastoreError(err)
 	if err == datastore.ErrNoSuchEntity {
 		if _, err := tx.Put(p.Key(), p); err != nil {
 			return nil, err
 		}
 		return p, nil
 	}
 	if err != nil {
 		return nil, err
 	}
 	return p, nil
 }

 type builderAndGoHash struct {
 	builder, goHash string
 }

 // A Commit describes an individual commit in a package.
 //
 // Each Commit entity is a descendant of its associated Package entity.
 // In other words, all Commits with the same PackagePath belong to the same
 // datastore entity group.
 type Commit struct {
 	PackagePath string // (empty for main repo commits)
 	Hash        string

 	// ResultData is the Data string of each build Result for this Commit.
 	// For non-Go commits, only the Results for the current Go tip, weekly,
 	// and release Tags are stored here. This is purely de-normalized data.
 	// The complete data set is stored in Result entities.
 	ResultData []string `datastore:",noindex"`
 }

 func (com *Commit) Key() *datastore.Key {
 	if com.Hash == "" {
 		panic("tried Key on Commit with empty Hash")
 	}
 	p := Package{Path: com.PackagePath}
 	key := com.PackagePath + "|" + com.Hash
 	return dsKey("Commit", key, p.Key())
 }

 // Valid reports whether the commit is valid.
 func (c *Commit) Valid() bool {
 	// Valid really just means the hash is populated.
 	return validHash(c.Hash)
 }

 // each result line is approx 105 bytes. This constant is a tradeoff between
 // build history and the AppEngine datastore limit of 1mb.
 const maxResults = 1000

 // AddResult adds the denormalized Result data to the Commit's
 // ResultData field.
 func (com *Commit) AddResult(tx *datastore.Transaction, r *Result) error {
 	err := tx.Get(com.Key(), com)
 	if err == datastore.ErrNoSuchEntity {
 		// If it doesn't exist, we create it below.
 	} else {
 		err = filterDatastoreError(err)
 		if err != nil {
 			return fmt.Errorf("Commit.AddResult, getting Commit: %v", err)
 		}
 	}

 	var resultExists bool
 	for i, s := range com.ResultData {
 		// if there already exists result data for this builder at com, overwrite it.
 		if strings.HasPrefix(s, r.Builder+"|") && strings.HasSuffix(s, "|"+r.GoHash) {
 			resultExists = true
 			com.ResultData[i] = r.Data()
 		}
 	}
 	if !resultExists {
 		// otherwise, add the new result data for this builder.
 		com.ResultData = trim(append(com.ResultData, r.Data()), maxResults)
 	}
 	if !com.Valid() {
 		return errors.New("putting Commit: commit is not valid")
 	}
 	if _, err := tx.Put(com.Key(), com); err != nil {
 		return fmt.Errorf("putting Commit: %v", err)
 	}
 	return nil
 }

 // removeResult removes the denormalized Result data from the ResultData field
 // for the given builder and go hash.
 // It must be called from within the datastore transaction that gets and puts
 // the Commit. Note this is slightly different to AddResult, above.
 func (com *Commit) RemoveResult(r *Result) {
 	var rd []string
 	for _, s := range com.ResultData {
 		if strings.HasPrefix(s, r.Builder+"|") && strings.HasSuffix(s, "|"+r.GoHash) {
 			continue
 		}
 		rd = append(rd, s)
 	}
 	com.ResultData = rd
 }

 func trim(s []string, n int) []string {
 	l := min(len(s), n)
 	return s[len(s)-l:]
 }

 func min(a, b int) int {
 	if a < b {
 		return a
 	}
 	return b
 }

 // Result returns the build Result for this Commit for the given builder/goHash.
 //
 // For the main Go repo, goHash is the empty string.
 func (c *Commit) Result(builder, goHash string) *Result {
 	return result(c.ResultData, c.Hash, c.PackagePath, builder, goHash)
 }

 // Result returns the build Result for this commit for the given builder/goHash.
 //
 // For the main Go repo, goHash is the empty string.
 func (c *CommitInfo) Result(builder, goHash string) *Result {
 	if r := result(c.ResultData, c.Hash, c.PackagePath, builder, goHash); r != nil {
 		return r
 	}
 	if u, ok := c.BuildingURLs[builderAndGoHash{builder, goHash}]; ok {
 		return &Result{
 			Builder:     builder,
 			BuildingURL: u,
 			Hash:        c.Hash,
 			GoHash:      goHash,
 		}
 	}
 	if *fakeResults {
 		switch rand.Intn(3) {
 		default:
 			return nil
 		case 1:
 			return &Result{
 				Builder: builder,
 				Hash:    c.Hash,
 				GoHash:  goHash,
 				OK:      true,
 			}
 		case 2:
 			return &Result{
 				Builder: builder,
 				Hash:    c.Hash,
 				GoHash:  goHash,
 				LogHash: "fakefailureurl",
 			}
 		}
 	}
 	return nil
 }

 func result(resultData []string, hash, packagePath, builder, goHash string) *Result {
 	for _, r := range resultData {
 		if !strings.HasPrefix(r, builder) {
 			// Avoid strings.SplitN alloc in the common case.
 			continue
 		}
 		p := strings.SplitN(r, "|", 4)
 		if len(p) != 4 || p[0] != builder || p[3] != goHash {
 			continue
 		}
 		return partsToResult(hash, packagePath, p)
 	}
 	return nil
 }

 // isUntested reports whether a cell in the build.golang.org grid is
 // an untested configuration.
 //
 // repo is "go", "net", etc.
 // branch is the branch of repo "master" or "release-branch.go1.12"
 // goBranch applies only if repo != "go" and is of form "master" or "release-branch.go1.N"
 //
 // As a special case, "tip" is an alias for "master", since this app
 // still uses a bunch of hg terms from when we used hg.
 func isUntested(builder, repo, branch, goBranch string) bool {
 	if branch == "tip" {
 		branch = "master"
 	}
 	if goBranch == "tip" {
 		goBranch = "master"
 	}
 	bc, ok := dashboard.Builders[builder]
 	if !ok {
 		// Unknown builder, so not tested.
 		return true
 	}
 	return !bc.BuildsRepoPostSubmit(repo, branch, goBranch)
 }

 // knownIssue returns a known issue for the named builder,
 // or zero if there isn't a known issue.
 func knownIssue(builder string) int {
 	bc, ok := dashboard.Builders[builder]
 	if !ok {
 		// Unknown builder.
 		return 0
 	}
 	return bc.KnownIssue
 }

 // Results returns the build Results for this Commit.
 func (c *CommitInfo) Results() (results []*Result) {
 	for _, r := range c.ResultData {
 		p := strings.SplitN(r, "|", 4)
 		if len(p) != 4 {
 			continue
 		}
 		results = append(results, partsToResult(c.Hash, c.PackagePath, p))
 	}
 	return
 }

 // ResultGoHashes, for non-go repos, returns the list of Go hashes that
 // this repo has been (or should be) built at.
 //
 // For the main Go repo it always returns a slice with 1 element: the
 // empty string.
 func (c *CommitInfo) ResultGoHashes() []string {
 	// For the main repo, just return the empty string
 	// (there's no corresponding main repo hash for a main repo Commit).
 	// This function is only really useful for sub-repos.
 	if c.PackagePath == "" {
 		return []string{""}
 	}
 	var hashes []string
 	for _, r := range c.ResultData {
 		p := strings.SplitN(r, "|", 4)
 		if len(p) != 4 {
 			continue
 		}
 		// Append only new results (use linear scan to preserve order).
 		if !contains(hashes, p[3]) {
 			hashes = append(hashes, p[3])
 		}
 	}
 	// Return results in reverse order (newest first).
 	reverse(hashes)
 	return hashes
 }

 func contains(t []string, s string) bool {
 	for _, s2 := range t {
 		if s2 == s {
 			return true
 		}
 	}
 	return false
 }

 func reverse(s []string) {
 	for i := 0; i < len(s)/2; i++ {
 		j := len(s) - i - 1
 		s[i], s[j] = s[j], s[i]
 	}
 }

 // partsToResult creates a Result from ResultData substrings.
 func partsToResult(hash, packagePath string, p []string) *Result {
 	return &Result{
 		Builder:     p[0],
 		Hash:        hash,
 		PackagePath: packagePath,
 		GoHash:      p[3],
 		OK:          p[1] == "true",
 		LogHash:     p[2],
 	}
 }

 // A Result describes a build result for a Commit on an OS/architecture.
 //
 // Each Result entity is a descendant of its associated Package entity.
 type Result struct {
 	Builder     string // "os-arch[-note]"
 	PackagePath string // (empty for Go commits, else "golang.org/x/foo")
 	Hash        string

 	// The Go Commit this was built against (when PackagePath != ""; empty for Go commits).
 	GoHash string

 	BuildingURL string `datastore:"-"` // non-empty if currently building
 	OK          bool
 	Log         string `datastore:"-"`        // for JSON unmarshaling only
 	LogHash     string `datastore:",noindex"` // Key to the Log record.

 	RunTime int64 // time to build+test in nanoseconds
 }

 func (r *Result) Key() *datastore.Key {
 	p := Package{Path: r.PackagePath}
 	key := r.Builder + "|" + r.PackagePath + "|" + r.Hash + "|" + r.GoHash
 	return dsKey("Result", key, p.Key())
 }

 func (r *Result) Valid() error {
 	if !validHash(r.Hash) {
 		return errors.New("invalid Hash")
 	}
 	if r.PackagePath != "" && !validHash(r.GoHash) {
 		return errors.New("invalid GoHash")
 	}
 	return nil
 }

 // Data returns the Result in string format
 // to be stored in Commit's ResultData field.
 func (r *Result) Data() string {
 	return fmt.Sprintf("%v|%v|%v|%v", r.Builder, r.OK, r.LogHash, r.GoHash)
 }

 // A Log is a gzip-compressed log file stored under the SHA1 hash of the
 // uncompressed log text.
 type Log struct {
 	CompressedLog []byte `datastore:",noindex"`
 }

 func (l *Log) Text() ([]byte, error) {
 	d, err := gzip.NewReader(bytes.NewBuffer(l.CompressedLog))
 	if err != nil {
 		return nil, fmt.Errorf("reading log data: %v", err)
 	}
 	b, err := ioutil.ReadAll(d)
 	if err != nil {
 		return nil, fmt.Errorf("reading log data: %v", err)
 	}
 	return b, nil
 }

 func PutLog(c context.Context, text string) (hash string, err error) {
 	b := new(bytes.Buffer)
 	z, _ := gzip.NewWriterLevel(b, gzip.BestCompression)
 	io.WriteString(z, text)
 	z.Close()
 	hash = loghash.New(text)
 	key := dsKey("Log", hash, nil)
 	_, err = datastoreClient.Put(c, key, &Log{b.Bytes()})
 	return
 }
	// Copyright 2011 The Go Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style
	// license that can be found in the LICENSE file.

	package main

	import (
	"bytes"
	"compress/gzip"
	"context"
	"errors"
	"fmt"
	"io"
	"io/ioutil"
	"math/rand"
	pathpkg "path"
	"strings"

	"cloud.google.com/go/datastore"
	"golang.org/x/build/dashboard"
	"golang.org/x/build/internal/loghash"
	)

	const (
	maxDatastoreStringLen = 500
	)

	func dsKey(kind, name string, parent datastore.Key) datastore.Key {
	dk := datastore.NameKey(kind, name, parent)
	dk.Namespace = "Git"
	return dk
	}

	// A Package describes a package that is listed on the dashboard.
	type Package struct {
	Name string // "Go", "arch", "net", ...
	Path string // empty for the main Go tree, else "golang.org/x/foo"
	}

	func (p *Package) String() string {
	return fmt.Sprintf("%s: %q", p.Path, p.Name)
	}

	func (p Package) Key() datastore.Key {
	key := p.Path
	if key == "" {
	key = "go"
	}
	return dsKey("Package", key, nil)
	}

	// filterDatastoreError returns err, unless it's just about datastore
	// not being able to load an entity with old legacy struct fields into
	// the Commit type that has since removed those fields.
	func filterDatastoreError(err error) error {
	return filterAppEngineError(err, func(err error) bool {
	if em, ok := err.(*datastore.ErrFieldMismatch); ok {
	switch em.FieldName {
	case "NeedsBenchmarking", "TryPatch", "FailNotificationSent":
	// Removed in CLs 208397 and 208324.
	return true
	case "PackagePath", "ParentHash", "Num", "User", "Desc", "Time", "Branch", "NextNum", "Kind":
	// Removed in move to maintner in CL 208697.
	return true
	}
	}
	return false
	})
	}

	// filterNoSuchEntity returns err, unless it's just about datastore
	// not being able to load an entity because it doesn't exist.
	func filterNoSuchEntity(err error) error {
	return filterAppEngineError(err, func(err error) bool {
	return err == datastore.ErrNoSuchEntity
	})
	}

	// filterAppEngineError returns err, unless ignore(err) is true,
	// in which case it returns nil. If err is an datastore.MultiError,
	// it returns either nil (if all errors are ignored) or a deep copy
	// with the non-ignored errors.
	func filterAppEngineError(err error, ignore func(error) bool) error {
	if err == nil \|\| ignore(err) {
	return nil
	}
	if me, ok := err.(datastore.MultiError); ok {
	me2 := make(datastore.MultiError, 0, len(me))
	for _, err := range me {
	if e2 := filterAppEngineError(err, ignore); e2 != nil {
	me2 = append(me2, e2)
	}
	}
	if len(me2) == 0 {
	return nil
	}
	return me2
	}
	return err
	}

	// getOrMakePackageInTx fetches a Package by path from the datastore,
	// creating it if necessary.
	func getOrMakePackageInTx(ctx context.Context, tx datastore.Transaction, path string) (Package, error) {
	p := &Package{Path: path}
	if path != "" {
	p.Name = pathpkg.Base(path)
	} else {
	p.Name = "Go"
	}
	err := tx.Get(p.Key(), p)
	err = filterDatastoreError(err)
	if err == datastore.ErrNoSuchEntity {
	if _, err := tx.Put(p.Key(), p); err != nil {
	return nil, err
	}
	return p, nil
	}
	if err != nil {
	return nil, err
	}
	return p, nil
	}

	type builderAndGoHash struct {
	builder, goHash string
	}

	// A Commit describes an individual commit in a package.
	//
	// Each Commit entity is a descendant of its associated Package entity.
	// In other words, all Commits with the same PackagePath belong to the same
	// datastore entity group.
	type Commit struct {
	PackagePath string // (empty for main repo commits)
	Hash string

	// ResultData is the Data string of each build Result for this Commit.
	// For non-Go commits, only the Results for the current Go tip, weekly,
	// and release Tags are stored here. This is purely de-normalized data.
	// The complete data set is stored in Result entities.
	ResultData []string `datastore:",noindex"`
	}

	func (com Commit) Key() datastore.Key {
	if com.Hash == "" {
	panic("tried Key on Commit with empty Hash")
	}
	p := Package{Path: com.PackagePath}
	key := com.PackagePath + "\|" + com.Hash
	return dsKey("Commit", key, p.Key())
	}

	// Valid reports whether the commit is valid.
	func (c *Commit) Valid() bool {
	// Valid really just means the hash is populated.
	return validHash(c.Hash)
	}

	// each result line is approx 105 bytes. This constant is a tradeoff between
	// build history and the AppEngine datastore limit of 1mb.
	const maxResults = 1000

	// AddResult adds the denormalized Result data to the Commit's
	// ResultData field.
	func (com Commit) AddResult(tx datastore.Transaction, r *Result) error {
	err := tx.Get(com.Key(), com)
	if err == datastore.ErrNoSuchEntity {
	// If it doesn't exist, we create it below.
	} else {
	err = filterDatastoreError(err)
	if err != nil {
	return fmt.Errorf("Commit.AddResult, getting Commit: %v", err)
	}
	}

	var resultExists bool
	for i, s := range com.ResultData {
	// if there already exists result data for this builder at com, overwrite it.
	if strings.HasPrefix(s, r.Builder+"\|") && strings.HasSuffix(s, "\|"+r.GoHash) {
	resultExists = true
	com.ResultData[i] = r.Data()
	}
	}
	if !resultExists {
	// otherwise, add the new result data for this builder.
	com.ResultData = trim(append(com.ResultData, r.Data()), maxResults)
	}
	if !com.Valid() {
	return errors.New("putting Commit: commit is not valid")
	}
	if _, err := tx.Put(com.Key(), com); err != nil {
	return fmt.Errorf("putting Commit: %v", err)
	}
	return nil
	}

	// removeResult removes the denormalized Result data from the ResultData field
	// for the given builder and go hash.
	// It must be called from within the datastore transaction that gets and puts
	// the Commit. Note this is slightly different to AddResult, above.
	func (com Commit) RemoveResult(r Result) {
	var rd []string
	for _, s := range com.ResultData {
	if strings.HasPrefix(s, r.Builder+"\|") && strings.HasSuffix(s, "\|"+r.GoHash) {
	continue
	}
	rd = append(rd, s)
	}
	com.ResultData = rd
	}

	func trim(s []string, n int) []string {
	l := min(len(s), n)
	return s[len(s)-l:]
	}

	func min(a, b int) int {
	if a < b {
	return a
	}
	return b
	}

	// Result returns the build Result for this Commit for the given builder/goHash.
	//
	// For the main Go repo, goHash is the empty string.
	func (c Commit) Result(builder, goHash string) Result {
	return result(c.ResultData, c.Hash, c.PackagePath, builder, goHash)
	}

	// Result returns the build Result for this commit for the given builder/goHash.
	//
	// For the main Go repo, goHash is the empty string.
	func (c CommitInfo) Result(builder, goHash string) Result {
	if r := result(c.ResultData, c.Hash, c.PackagePath, builder, goHash); r != nil {
	return r
	}
	if u, ok := c.BuildingURLs[builderAndGoHash{builder, goHash}]; ok {
	return &Result{
	Builder: builder,
	BuildingURL: u,
	Hash: c.Hash,
	GoHash: goHash,
	}
	}
	if *fakeResults {
	switch rand.Intn(3) {
	default:
	return nil
	case 1:
	return &Result{
	Builder: builder,
	Hash: c.Hash,
	GoHash: goHash,
	OK: true,
	}
	case 2:
	return &Result{
	Builder: builder,
	Hash: c.Hash,
	GoHash: goHash,
	LogHash: "fakefailureurl",
	}
	}
	}
	return nil
	}

	func result(resultData []string, hash, packagePath, builder, goHash string) *Result {
	for _, r := range resultData {
	if !strings.HasPrefix(r, builder) {
	// Avoid strings.SplitN alloc in the common case.
	continue
	}
	p := strings.SplitN(r, "\|", 4)
	if len(p) != 4 \|\| p[0] != builder \|\| p[3] != goHash {
	continue
	}
	return partsToResult(hash, packagePath, p)
	}
	return nil
	}

	// isUntested reports whether a cell in the build.golang.org grid is
	// an untested configuration.
	//
	// repo is "go", "net", etc.
	// branch is the branch of repo "master" or "release-branch.go1.12"
	// goBranch applies only if repo != "go" and is of form "master" or "release-branch.go1.N"
	//
	// As a special case, "tip" is an alias for "master", since this app
	// still uses a bunch of hg terms from when we used hg.
	func isUntested(builder, repo, branch, goBranch string) bool {
	if branch == "tip" {
	branch = "master"
	}
	if goBranch == "tip" {
	goBranch = "master"
	}
	bc, ok := dashboard.Builders[builder]
	if !ok {
	// Unknown builder, so not tested.
	return true
	}
	return !bc.BuildsRepoPostSubmit(repo, branch, goBranch)
	}

	// knownIssue returns a known issue for the named builder,
	// or zero if there isn't a known issue.
	func knownIssue(builder string) int {
	bc, ok := dashboard.Builders[builder]
	if !ok {
	// Unknown builder.
	return 0
	}
	return bc.KnownIssue
	}

	// Results returns the build Results for this Commit.
	func (c CommitInfo) Results() (results []Result) {
	for _, r := range c.ResultData {
	p := strings.SplitN(r, "\|", 4)
	if len(p) != 4 {
	continue
	}
	results = append(results, partsToResult(c.Hash, c.PackagePath, p))
	}
	return
	}

	// ResultGoHashes, for non-go repos, returns the list of Go hashes that
	// this repo has been (or should be) built at.
	//
	// For the main Go repo it always returns a slice with 1 element: the
	// empty string.
	func (c *CommitInfo) ResultGoHashes() []string {
	// For the main repo, just return the empty string
	// (there's no corresponding main repo hash for a main repo Commit).
	// This function is only really useful for sub-repos.
	if c.PackagePath == "" {
	return []string{""}
	}
	var hashes []string
	for _, r := range c.ResultData {
	p := strings.SplitN(r, "\|", 4)
	if len(p) != 4 {
	continue
	}
	// Append only new results (use linear scan to preserve order).
	if !contains(hashes, p[3]) {
	hashes = append(hashes, p[3])
	}
	}
	// Return results in reverse order (newest first).
	reverse(hashes)
	return hashes
	}

	func contains(t []string, s string) bool {
	for _, s2 := range t {
	if s2 == s {
	return true
	}
	}
	return false
	}

	func reverse(s []string) {
	for i := 0; i < len(s)/2; i++ {
	j := len(s) - i - 1
	s[i], s[j] = s[j], s[i]
	}
	}

	// partsToResult creates a Result from ResultData substrings.
	func partsToResult(hash, packagePath string, p []string) *Result {
	return &Result{
	Builder: p[0],
	Hash: hash,
	PackagePath: packagePath,
	GoHash: p[3],
	OK: p[1] == "true",
	LogHash: p[2],
	}
	}

	// A Result describes a build result for a Commit on an OS/architecture.
	//
	// Each Result entity is a descendant of its associated Package entity.
	type Result struct {
	Builder string // "os-arch[-note]"
	PackagePath string // (empty for Go commits, else "golang.org/x/foo")
	Hash string

	// The Go Commit this was built against (when PackagePath != ""; empty for Go commits).
	GoHash string

	BuildingURL string `datastore:"-"` // non-empty if currently building
	OK bool
	Log string `datastore:"-"` // for JSON unmarshaling only
	LogHash string `datastore:",noindex"` // Key to the Log record.

	RunTime int64 // time to build+test in nanoseconds
	}

	func (r Result) Key() datastore.Key {
	p := Package{Path: r.PackagePath}
	key := r.Builder + "\|" + r.PackagePath + "\|" + r.Hash + "\|" + r.GoHash
	return dsKey("Result", key, p.Key())
	}

	func (r *Result) Valid() error {
	if !validHash(r.Hash) {
	return errors.New("invalid Hash")
	}
	if r.PackagePath != "" && !validHash(r.GoHash) {
	return errors.New("invalid GoHash")
	}
	return nil
	}

	// Data returns the Result in string format
	// to be stored in Commit's ResultData field.
	func (r *Result) Data() string {
	return fmt.Sprintf("%v\|%v\|%v\|%v", r.Builder, r.OK, r.LogHash, r.GoHash)
	}

	// A Log is a gzip-compressed log file stored under the SHA1 hash of the
	// uncompressed log text.
	type Log struct {
	CompressedLog []byte `datastore:",noindex"`
	}

	func (l *Log) Text() ([]byte, error) {
	d, err := gzip.NewReader(bytes.NewBuffer(l.CompressedLog))
	if err != nil {
	return nil, fmt.Errorf("reading log data: %v", err)
	}
	b, err := ioutil.ReadAll(d)
	if err != nil {
	return nil, fmt.Errorf("reading log data: %v", err)
	}
	return b, nil
	}

	func PutLog(c context.Context, text string) (hash string, err error) {
	b := new(bytes.Buffer)
	z, _ := gzip.NewWriterLevel(b, gzip.BestCompression)
	io.WriteString(z, text)
	z.Close()
	hash = loghash.New(text)
	key := dsKey("Log", hash, nil)
	_, err = datastoreClient.Put(c, key, &Log{b.Bytes()})
	return
	}