build/builder.go - zoekt - Git at Google

 // Copyright 2016 Google Inc. All rights reserved.
 //
 // 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 build implements a more convenient interface for building
 // zoekt indices.
 package build

 import (
 	"fmt"
 	"io/ioutil"
 	"log"
 	"os"
 	"os/exec"
 	"path/filepath"
 	"runtime"
 	"runtime/pprof"
 	"strings"
 	"sync"

 	"github.com/google/zoekt"
 )

 var DefaultDir = filepath.Join(os.Getenv("HOME"), ".zoekt")

 // Branch describes a single branch version.
 type Branch struct {
 	Name    string
 	Version string
 }

 // Options sets options for the index building.
 type Options struct {
 	// IndexDir is a directory that holds *.zoekt index files.
 	IndexDir string

 	// SizeMax is the maximum file size
 	SizeMax int

 	// Parallelism is the maximum number of shards to index in parallel
 	Parallelism int

 	// ShardMax sets the maximum corpus size for a single shard
 	ShardMax int

 	// RepositoryDescription holds names and URLs for the repository.
 	RepositoryDescription zoekt.Repository

 	// SubRepositories is a path => sub repository map.
 	SubRepositories map[string]*zoekt.Repository

 	// RepoDir is the path to the repository on the indexing machine.
 	RepoDir string

 	// Path to exuberant ctags binary to run
 	CTags string

 	// If set, ctags must succeed.
 	CTagsMustSucceed bool

 	// Path to namespace-sandbox from Bazel
 	NamespaceSandbox string

 	// Write memory profiles to this file.
 	MemProfile string
 }

 // Builder manages (parallel) creation of uniformly sized shards.
 type Builder struct {
 	opts     Options
 	throttle chan int

 	nextShardNum int
 	todo         []*zoekt.Document
 	size         int

 	building sync.WaitGroup

 	errMu      sync.Mutex
 	buildError error

 	// temp name => final name for finished shards. We only rename
 	// them once all shards succeed to avoid Frankstein corpuses.
 	finishedShards map[string]string
 }

 // SetDefaults sets reasonable default options.
 func (o *Options) SetDefaults() {
 	if o.CTags == "" {
 		ctags, err := exec.LookPath("ctags-universal")
 		if err == nil {
 			o.CTags = ctags
 		}
 	}

 	if o.CTags == "" {
 		ctags, err := exec.LookPath("ctags-exuberant")
 		if err == nil {
 			o.CTags = ctags
 		}
 	}
 	if o.NamespaceSandbox == "" {
 		ns, err := exec.LookPath("zoekt-sandbox")
 		if err == nil {
 			o.NamespaceSandbox = ns
 		}
 	}
 	if o.Parallelism == 0 {
 		o.Parallelism = 1
 	}
 	if o.SizeMax == 0 {
 		o.SizeMax = 128 << 10
 	}
 	if o.ShardMax == 0 {
 		o.ShardMax = 128 << 20
 	}
 }

 // ShardName returns the name the given index shard.
 func (o *Options) shardName(n int) (string, error) {
 	abs, err := filepath.Abs(o.RepoDir)
 	if err != nil {
 		return "", err
 	}

 	return filepath.Join(o.IndexDir,
 		fmt.Sprintf("%s_v%d.%05d.zoekt", strings.Replace(abs, "/", "_", -1), zoekt.IndexFormatVersion, n)), nil
 }

 // IndexVersions returns the versions as present in the index, for
 // implementing incremental indexing.
 func (o *Options) IndexVersions() []zoekt.RepositoryBranch {
 	fn, err := o.shardName(0)
 	if err != nil {
 		return nil
 	}
 	f, err := os.Open(fn)
 	if err != nil {
 		return nil
 	}

 	iFile, err := zoekt.NewIndexFile(f)
 	if err != nil {
 		return nil
 	}
 	defer iFile.Close()

 	repo, index, err := zoekt.ReadMetadata(iFile)
 	if err != nil {
 		return nil
 	}

 	if index.IndexFeatureVersion != zoekt.FeatureVersion {
 		return nil
 	}

 	return repo.Branches
 }

 // NewBuilder creates a new Builder instance.
 func NewBuilder(opt Options) (*Builder, error) {
 	if opt.RepoDir == "" {
 		return nil, fmt.Errorf("must set options.RepoDir")
 	}

 	b := &Builder{
 		opts:           opt,
 		throttle:       make(chan int, opt.Parallelism),
 		finishedShards: map[string]string{},
 	}

 	if _, err := b.newShardBuilder(); err != nil {
 		return nil, err
 	}

 	return b, nil
 }

 func (b *Builder) AddFile(name string, content []byte) {
 	b.Add(zoekt.Document{Name: name, Content: content})
 }

 func (b *Builder) Add(doc zoekt.Document) error {
 	if len(doc.Content) > b.opts.SizeMax {
 		return nil
 	}

 	if !zoekt.IsText(doc.Content) {
 		return nil
 	}

 	b.todo = append(b.todo, &doc)
 	b.size += len(doc.Name) + len(doc.Content)
 	if b.size > b.opts.ShardMax {
 		return b.flush()
 	}

 	return nil
 }

 func (b *Builder) Finish() error {
 	b.flush()
 	b.building.Wait()

 	if b.buildError != nil {
 		for tmp := range b.finishedShards {
 			os.Remove(tmp)
 		}
 		return b.buildError
 	}

 	for tmp, final := range b.finishedShards {
 		if err := os.Rename(tmp, final); err != nil {
 			b.buildError = err
 		}
 	}

 	if b.nextShardNum > 0 {
 		b.deleteRemainingShards()
 	}
 	return b.buildError
 }

 func (b *Builder) deleteRemainingShards() {
 	for {
 		shard := b.nextShardNum
 		b.nextShardNum++
 		name, err := b.opts.shardName(shard)
 		if err != nil {
 			break
 		}

 		if err := os.Remove(name); os.IsNotExist(err) {
 			break
 		}
 	}
 }

 func (b *Builder) flush() error {
 	todo := b.todo
 	b.todo = nil
 	b.size = 0
 	b.errMu.Lock()
 	defer b.errMu.Unlock()
 	if b.buildError != nil {
 		return b.buildError
 	}

 	if len(todo) == 0 {
 		return nil
 	}

 	shard := b.nextShardNum
 	b.nextShardNum++

 	if b.opts.Parallelism > 1 {
 		b.building.Add(1)
 		go func() {
 			b.throttle <- 1
 			err := b.buildShard(todo, shard)
 			<-b.throttle

 			b.errMu.Lock()
 			defer b.errMu.Unlock()
 			if err != nil && b.buildError == nil {
 				b.buildError = err
 			}
 			b.building.Done()
 		}()
 	} else {
 		// No goroutines when we're not parallel. This
 		// simplifies memory profiling.
 		b.buildError = b.buildShard(todo, shard)

 		if b.opts.MemProfile != "" {
 			// drop memory, and profile.
 			todo = nil
 			b.writeMemProfile(b.opts.MemProfile)
 		}

 		return b.buildError
 	}

 	return nil
 }

 var profileNumber int

 func (b *Builder) writeMemProfile(name string) {
 	nm := fmt.Sprintf("%s.%d", name, profileNumber)
 	profileNumber++
 	f, err := os.Create(nm)
 	if err != nil {
 		log.Fatal("could not create memory profile: ", err)
 	}
 	runtime.GC() // get up-to-date statistics
 	if err := pprof.WriteHeapProfile(f); err != nil {
 		log.Fatal("could not write memory profile: ", err)
 	}
 	f.Close()
 	log.Printf("wrote mem profile %q", nm)
 }

 func (b *Builder) buildShard(todo []*zoekt.Document, nextShardNum int) error {
 	if b.opts.CTags == "" && b.opts.CTagsMustSucceed {
 		return fmt.Errorf("ctags binary not found, but CTagsMustSucceed set.")
 	}
 	if b.opts.CTags != "" {
 		err := ctagsAddSymbols(todo, b.opts.CTags, b.opts.NamespaceSandbox)
 		if b.opts.CTagsMustSucceed && err != nil {
 			return err
 		}
 		if err != nil {
 			log.Printf("ignoring %s error: %v", b.opts.CTags, err)
 		}
 	}

 	name, err := b.opts.shardName(nextShardNum)
 	if err != nil {
 		return err
 	}

 	shardBuilder, err := b.newShardBuilder()
 	if err != nil {
 		return err
 	}

 	for _, t := range todo {
 		shardBuilder.Add(*t)
 	}

 	if err := b.writeShard(name, shardBuilder); err != nil {
 		return err
 	}
 	return nil
 }

 func (b *Builder) newShardBuilder() (*zoekt.IndexBuilder, error) {
 	desc := b.opts.RepositoryDescription
 	desc.SubRepoMap = b.opts.SubRepositories

 	shardBuilder, err := zoekt.NewIndexBuilder(&desc)
 	if err != nil {
 		return nil, err
 	}
 	return shardBuilder, nil
 }

 func (b *Builder) writeShard(fn string, ib *zoekt.IndexBuilder) error {
 	dir := filepath.Dir(fn)
 	if err := os.MkdirAll(dir, 0700); err != nil {
 		return err
 	}

 	f, err := ioutil.TempFile(dir, filepath.Base(fn))
 	if err != nil {
 		return err
 	}

 	defer f.Close()
 	if err := ib.Write(f); err != nil {
 		return err
 	}
 	fi, err := f.Stat()
 	if err != nil {
 		return err
 	}
 	if err := f.Close(); err != nil {
 		return err
 	}

 	b.finishedShards[f.Name()] = fn
 	log.Printf("finished %s: %d index bytes (overhead %3.1f)", fn, fi.Size(),
 		float64(fi.Size())/float64(ib.ContentSize()+1))

 	return nil
 }
	// Copyright 2016 Google Inc. All rights reserved.
	//
	// 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 build implements a more convenient interface for building
	// zoekt indices.
	package build

	import (
	"fmt"
	"io/ioutil"
	"log"
	"os"
	"os/exec"
	"path/filepath"
	"runtime"
	"runtime/pprof"
	"strings"
	"sync"

	"github.com/google/zoekt"
	)

	var DefaultDir = filepath.Join(os.Getenv("HOME"), ".zoekt")

	// Branch describes a single branch version.
	type Branch struct {
	Name string
	Version string
	}

	// Options sets options for the index building.
	type Options struct {
	// IndexDir is a directory that holds *.zoekt index files.
	IndexDir string

	// SizeMax is the maximum file size
	SizeMax int

	// Parallelism is the maximum number of shards to index in parallel
	Parallelism int

	// ShardMax sets the maximum corpus size for a single shard
	ShardMax int

	// RepositoryDescription holds names and URLs for the repository.
	RepositoryDescription zoekt.Repository

	// SubRepositories is a path => sub repository map.
	SubRepositories map[string]*zoekt.Repository

	// RepoDir is the path to the repository on the indexing machine.
	RepoDir string

	// Path to exuberant ctags binary to run
	CTags string

	// If set, ctags must succeed.
	CTagsMustSucceed bool

	// Path to namespace-sandbox from Bazel
	NamespaceSandbox string

	// Write memory profiles to this file.
	MemProfile string
	}

	// Builder manages (parallel) creation of uniformly sized shards.
	type Builder struct {
	opts Options
	throttle chan int

	nextShardNum int
	todo []*zoekt.Document
	size int

	building sync.WaitGroup

	errMu sync.Mutex
	buildError error

	// temp name => final name for finished shards. We only rename
	// them once all shards succeed to avoid Frankstein corpuses.
	finishedShards map[string]string
	}

	// SetDefaults sets reasonable default options.
	func (o *Options) SetDefaults() {
	if o.CTags == "" {
	ctags, err := exec.LookPath("ctags-universal")
	if err == nil {
	o.CTags = ctags
	}
	}

	if o.CTags == "" {
	ctags, err := exec.LookPath("ctags-exuberant")
	if err == nil {
	o.CTags = ctags
	}
	}
	if o.NamespaceSandbox == "" {
	ns, err := exec.LookPath("zoekt-sandbox")
	if err == nil {
	o.NamespaceSandbox = ns
	}
	}
	if o.Parallelism == 0 {
	o.Parallelism = 1
	}
	if o.SizeMax == 0 {
	o.SizeMax = 128 << 10
	}
	if o.ShardMax == 0 {
	o.ShardMax = 128 << 20
	}
	}

	// ShardName returns the name the given index shard.
	func (o *Options) shardName(n int) (string, error) {
	abs, err := filepath.Abs(o.RepoDir)
	if err != nil {
	return "", err
	}

	return filepath.Join(o.IndexDir,
	fmt.Sprintf("%s_v%d.%05d.zoekt", strings.Replace(abs, "/", "_", -1), zoekt.IndexFormatVersion, n)), nil
	}

	// IndexVersions returns the versions as present in the index, for
	// implementing incremental indexing.
	func (o *Options) IndexVersions() []zoekt.RepositoryBranch {
	fn, err := o.shardName(0)
	if err != nil {
	return nil
	}
	f, err := os.Open(fn)
	if err != nil {
	return nil
	}

	iFile, err := zoekt.NewIndexFile(f)
	if err != nil {
	return nil
	}
	defer iFile.Close()

	repo, index, err := zoekt.ReadMetadata(iFile)
	if err != nil {
	return nil
	}

	if index.IndexFeatureVersion != zoekt.FeatureVersion {
	return nil
	}

	return repo.Branches
	}

	// NewBuilder creates a new Builder instance.
	func NewBuilder(opt Options) (*Builder, error) {
	if opt.RepoDir == "" {
	return nil, fmt.Errorf("must set options.RepoDir")
	}

	b := &Builder{
	opts: opt,
	throttle: make(chan int, opt.Parallelism),
	finishedShards: map[string]string{},
	}

	if _, err := b.newShardBuilder(); err != nil {
	return nil, err
	}

	return b, nil
	}

	func (b *Builder) AddFile(name string, content []byte) {
	b.Add(zoekt.Document{Name: name, Content: content})
	}

	func (b *Builder) Add(doc zoekt.Document) error {
	if len(doc.Content) > b.opts.SizeMax {
	return nil
	}

	if !zoekt.IsText(doc.Content) {
	return nil
	}

	b.todo = append(b.todo, &doc)
	b.size += len(doc.Name) + len(doc.Content)
	if b.size > b.opts.ShardMax {
	return b.flush()
	}

	return nil
	}

	func (b *Builder) Finish() error {
	b.flush()
	b.building.Wait()

	if b.buildError != nil {
	for tmp := range b.finishedShards {
	os.Remove(tmp)
	}
	return b.buildError
	}

	for tmp, final := range b.finishedShards {
	if err := os.Rename(tmp, final); err != nil {
	b.buildError = err
	}
	}

	if b.nextShardNum > 0 {
	b.deleteRemainingShards()
	}
	return b.buildError
	}

	func (b *Builder) deleteRemainingShards() {
	for {
	shard := b.nextShardNum
	b.nextShardNum++
	name, err := b.opts.shardName(shard)
	if err != nil {
	break
	}

	if err := os.Remove(name); os.IsNotExist(err) {
	break
	}
	}
	}

	func (b *Builder) flush() error {
	todo := b.todo
	b.todo = nil
	b.size = 0
	b.errMu.Lock()
	defer b.errMu.Unlock()
	if b.buildError != nil {
	return b.buildError
	}

	if len(todo) == 0 {
	return nil
	}

	shard := b.nextShardNum
	b.nextShardNum++

	if b.opts.Parallelism > 1 {
	b.building.Add(1)
	go func() {
	b.throttle <- 1
	err := b.buildShard(todo, shard)
	<-b.throttle

	b.errMu.Lock()
	defer b.errMu.Unlock()
	if err != nil && b.buildError == nil {
	b.buildError = err
	}
	b.building.Done()
	}()
	} else {
	// No goroutines when we're not parallel. This
	// simplifies memory profiling.
	b.buildError = b.buildShard(todo, shard)

	if b.opts.MemProfile != "" {
	// drop memory, and profile.
	todo = nil
	b.writeMemProfile(b.opts.MemProfile)
	}

	return b.buildError
	}

	return nil
	}

	var profileNumber int

	func (b *Builder) writeMemProfile(name string) {
	nm := fmt.Sprintf("%s.%d", name, profileNumber)
	profileNumber++
	f, err := os.Create(nm)
	if err != nil {
	log.Fatal("could not create memory profile: ", err)
	}
	runtime.GC() // get up-to-date statistics
	if err := pprof.WriteHeapProfile(f); err != nil {
	log.Fatal("could not write memory profile: ", err)
	}
	f.Close()
	log.Printf("wrote mem profile %q", nm)
	}

	func (b Builder) buildShard(todo []zoekt.Document, nextShardNum int) error {
	if b.opts.CTags == "" && b.opts.CTagsMustSucceed {
	return fmt.Errorf("ctags binary not found, but CTagsMustSucceed set.")
	}
	if b.opts.CTags != "" {
	err := ctagsAddSymbols(todo, b.opts.CTags, b.opts.NamespaceSandbox)
	if b.opts.CTagsMustSucceed && err != nil {
	return err
	}
	if err != nil {
	log.Printf("ignoring %s error: %v", b.opts.CTags, err)
	}
	}

	name, err := b.opts.shardName(nextShardNum)
	if err != nil {
	return err
	}

	shardBuilder, err := b.newShardBuilder()
	if err != nil {
	return err
	}

	for _, t := range todo {
	shardBuilder.Add(*t)
	}

	if err := b.writeShard(name, shardBuilder); err != nil {
	return err
	}
	return nil
	}

	func (b Builder) newShardBuilder() (zoekt.IndexBuilder, error) {
	desc := b.opts.RepositoryDescription
	desc.SubRepoMap = b.opts.SubRepositories

	shardBuilder, err := zoekt.NewIndexBuilder(&desc)
	if err != nil {
	return nil, err
	}
	return shardBuilder, nil
	}

	func (b Builder) writeShard(fn string, ib zoekt.IndexBuilder) error {
	dir := filepath.Dir(fn)
	if err := os.MkdirAll(dir, 0700); err != nil {
	return err
	}

	f, err := ioutil.TempFile(dir, filepath.Base(fn))
	if err != nil {
	return err
	}

	defer f.Close()
	if err := ib.Write(f); err != nil {
	return err
	}
	fi, err := f.Stat()
	if err != nil {
	return err
	}
	if err := f.Close(); err != nil {
	return err
	}

	b.finishedShards[f.Name()] = fn
	log.Printf("finished %s: %d index bytes (overhead %3.1f)", fn, fi.Size(),
	float64(fi.Size())/float64(ib.ContentSize()+1))

	return nil
	}