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index.go
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index.go
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package ekanite
import (
"bufio"
"fmt"
"hash/fnv"
"io"
"os"
"path/filepath"
"sort"
"strconv"
"strings"
"sync"
"time"
"github.com/blevesearch/bleve"
"github.com/blevesearch/bleve/analysis/analyzers/custom_analyzer"
"github.com/blevesearch/bleve/analysis/tokenizers/regexp_tokenizer"
"github.com/ekanite/ekanite/query"
)
const (
endTimeFileName = "endtime"
indexNameLayout = "20060102_1504"
maxSearchHitSize = 10000
)
// DocID is a string, with the following configuration. It's 32-characters long, encoding 2
// 64-bit unsigned integers. When sorting DocIDs, the first 16 characters, reading from the
// left hand side represent the most significant 64-bit number. And therefore the next 16
// characters represent the least-significant 64-bit number.
type DocID string
type DocIDs []DocID
func (a DocIDs) Len() int { return len(a) }
func (a DocIDs) Less(i, j int) bool {
x := a[i]
y := a[j]
mustParse := func(s string) uint64 {
w, err := strconv.ParseUint(s, 16, 64)
if err != nil {
panic(fmt.Sprintf("failed to parse 64-bit word: %s", err.Error()))
}
return w
}
msw0 := mustParse(string(x[0:16]))
lsw0 := mustParse(string(x[16:32]))
msw1 := mustParse(string(y[0:16]))
lsw1 := mustParse(string(y[16:32]))
if msw0 == msw1 {
return lsw0 < lsw1
}
return msw0 < msw1
}
func (a DocIDs) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
// Document specifies the interface required by an object if it is to be indexed.
type Document interface {
ID() DocID
Data() interface{}
Source() []byte
}
// Index represents a collection of shards. It contains data for a specific time range.
type Index struct {
path string // Path to shard data
startTime time.Time // Start-time inclusive for this index
endTime time.Time // End-time exclusive for this index
Shards []*Shard // Individual bleve indexes
Alias bleve.IndexAlias // All bleve indexes as one reference, for search
}
type Indexes []*Index
// Indexes are ordered by decreasing end time.
// If two indexes have the same end time, then order by decreasing start time.
// This means that the first index in the slice covers the latest time range.
func (i Indexes) Len() int { return len(i) }
func (i Indexes) Less(u, v int) bool {
if i[u].endTime.After(i[v].endTime) {
return true
} else {
return i[u].startTime.After(i[v].startTime)
}
}
func (i Indexes) Swap(u, v int) { i[u], i[v] = i[v], i[u] }
// NewIndex returns an Index for the given start and end time, with the requested shards. It
// returns an error if an index already exists at the path.
func NewIndex(path string, startTime, endTime time.Time, numShards int) (*Index, error) {
indexName := startTime.UTC().Format(indexNameLayout)
indexPath := filepath.Join(path, indexName)
durationPath := filepath.Join(indexPath, endTimeFileName)
// Create the directory for the index, if it doesn't already exist.
if _, err := os.Stat(indexPath); err == nil && os.IsNotExist(err) {
return nil, fmt.Errorf("index already exists at %s", indexPath)
}
if err := os.MkdirAll(indexPath, 0755); err != nil {
return nil, err
}
// Insert the file with the duration information.
f, err := os.Create(durationPath)
if err != nil {
return nil, err
}
defer f.Close()
_, err = f.WriteString(endTime.UTC().Format(indexNameLayout))
if err != nil {
return nil, err
}
// Create the shards.
shards := make([]*Shard, 0, numShards)
for n := 0; n < numShards; n++ {
s := NewShard(filepath.Join(indexPath, strconv.Itoa(n)))
if err := s.Open(); err != nil {
return nil, err
}
shards = append(shards, s)
}
// Create alias for searching.
alias := bleve.NewIndexAlias()
for _, s := range shards {
alias.Add(s.b)
}
// Index is ready to go.
return &Index{
path: indexPath,
Shards: shards,
Alias: alias,
startTime: startTime,
endTime: endTime,
}, nil
}
// OpenIndex opens an existing index, at the given path.
func OpenIndex(path string) (*Index, error) {
fi, err := os.Stat(path)
if err != nil {
return nil, fmt.Errorf("failed to access index at %s", path)
}
if !fi.IsDir() {
return nil, fmt.Errorf("index %s path is not a directory", path)
}
// Get the start time and end time.
startTime, err := time.Parse(indexNameLayout, fi.Name())
if err != nil {
return nil, fmt.Errorf("unable to determine start time of index: %s", err.Error())
}
var endTime time.Time
if f, err := os.Open(filepath.Join(path, endTimeFileName)); err != nil {
return nil, fmt.Errorf("unable to open end time file for index: %s", err.Error())
} else {
defer f.Close()
r := bufio.NewReader(f)
if s, err := r.ReadString('\n'); err != nil && err != io.EOF {
return nil, fmt.Errorf("unable to determine end time of index: %s", err.Error())
} else {
endTime, err = time.Parse(indexNameLayout, s)
if err != nil {
return nil, fmt.Errorf("unable to parse end time from '%s': %s", s, err.Error())
}
}
}
// Get an index directory listing.
d, err := os.Open(path)
if err != nil {
return nil, err
}
fis, err := d.Readdir(0)
if err != nil {
return nil, err
}
// Open the shards.
shards := make([]*Shard, 0)
for _, fi := range fis {
if !fi.IsDir() || strings.HasPrefix(fi.Name(), ".") {
continue
}
s := NewShard(filepath.Join(path, fi.Name()))
if err := s.Open(); err != nil {
return nil, fmt.Errorf("shard open fail: %s", err.Error())
}
shards = append(shards, s)
}
// Create alias for searching.
alias := bleve.NewIndexAlias()
for _, s := range shards {
alias.Add(s.b)
}
// Index is ready to go.
return &Index{
path: path,
Shards: shards,
Alias: alias,
startTime: startTime,
endTime: endTime,
}, nil
}
// Path returns the path to storage for the index.
func (i *Index) Path() string { return i.path }
// StartTime returns the inclusive start time of the index.
func (i *Index) StartTime() time.Time { return i.startTime }
// EndTime returns the exclusive end time of the index.
func (i *Index) EndTime() time.Time { return i.endTime }
// Expired returns whether the index has expired at the given time, if the
// retention period is r.
func (i *Index) Expired(t time.Time, r time.Duration) bool {
return i.endTime.Add(r).Before(t)
}
// Total returns the number of documents in the index.
func (i *Index) Total() (uint64, error) {
var total uint64
for _, s := range i.Shards {
t, err := s.Total()
if err != nil {
return 0, err
}
total += t
}
return total, nil
}
// Contains returns whether the index's time range includes the given
// reference time.
func (i *Index) Contains(t time.Time) bool {
return (t.Equal(i.startTime) || t.After(i.startTime)) && t.Before(i.endTime)
}
// Index indexes the slice of documents in the index. It takes care of all shard routing.
func (i *Index) Index(documents []Document) error {
var wg sync.WaitGroup
shardBatches := make(map[*Shard][]Document, 0)
for _, d := range documents {
shard := i.Shard(d.ID())
shardBatches[shard] = append(shardBatches[shard], d)
}
// Index each batch in parallel.
for shard, batch := range shardBatches {
wg.Add(1)
go func(s *Shard, b []Document) {
defer wg.Done()
s.Index(b)
}(shard, batch)
}
wg.Wait()
return nil
}
// Search performs a search of the index using the given query. Returns IDs of documents
// which satisfy all queries. Returns Doc IDs in sorted order, ascending.
func (i *Index) Search(q string) (DocIDs, error) {
query := bleve.NewQueryStringQuery(q)
searchRequest := bleve.NewSearchRequest(query)
searchRequest.Size = maxSearchHitSize
searchResults, err := i.Alias.Search(searchRequest)
if err != nil {
return nil, err
}
docIDs := make(DocIDs, 0, len(searchResults.Hits))
for _, d := range searchResults.Hits {
docIDs = append(docIDs, DocID(d.ID))
}
sort.Sort(docIDs)
return docIDs, nil
}
// Document returns the source from the index for the given ID.
func (i *Index) Document(id DocID) ([]byte, error) {
s := i.Shard(id)
if s == nil {
return nil, fmt.Errorf("document %s not found", id)
}
return s.Document(id)
}
// Close closes the index.
func (i *Index) Close() error {
for _, s := range i.Shards {
if err := s.Close(); err != nil {
return err
}
}
return nil
}
// DeleteIndex deletes the index.
func DeleteIndex(i *Index) error {
_ = i.Close()
return os.RemoveAll(i.path)
}
// Shard returns the shard from the index, for the given doc ID.
func (i *Index) Shard(docId DocID) *Shard {
hasher := fnv.New32a()
hasher.Write([]byte(docId))
v := hasher.Sum32() % uint32(len(i.Shards))
return i.Shards[v]
}
// Shard is a the basic data store for indexed data. Indexing operations are not
// goroutine safe, and only 1 indexing operation should occur at one time.
type Shard struct {
path string
b bleve.Index // Underlying bleve index
}
// NewShard returns a shard using the data at the given path.
func NewShard(path string) *Shard {
return &Shard{
path: path,
}
}
// Opens the shard. If no data exists at the shard's path, an empty shard
// will be created.
func (s *Shard) Open() error {
_, err := os.Stat(s.path)
if err != nil && !os.IsNotExist(err) {
return fmt.Errorf("failed to check existence of shard")
} else if os.IsNotExist(err) {
mapping, err := buildIndexMapping()
if err != nil {
return err
}
s.b, err = bleve.New(s.path, mapping)
if err != nil {
return fmt.Errorf("bleve new: %s", err.Error())
}
} else {
s.b, err = bleve.Open(s.path)
if err != nil {
return fmt.Errorf("bleve open: %s", err.Error())
}
}
return nil
}
// Close closes the shard.
func (s *Shard) Close() error {
if err := s.b.Close(); err != nil {
return err
}
return nil
}
// Index indexes a slice of Documents in the shard.
func (s *Shard) Index(documents []Document) error {
batch := s.b.NewBatch()
for _, d := range documents {
if err := batch.Index(string(d.ID()), d.Data()); err != nil {
return err // XXX return errors en-masse
}
batch.SetInternal([]byte(d.ID()), d.Source())
}
if err := s.b.Batch(batch); err != nil {
return err
}
return nil
}
// Total returns the number of events in the shard.
func (s *Shard) Total() (uint64, error) {
return s.b.DocCount()
}
// Document returns the source from the shard for the given ID.
func (s *Shard) Document(id DocID) ([]byte, error) {
source, err := s.b.GetInternal([]byte(id))
if err != nil {
return nil, err
}
return source, nil
}
func buildIndexMapping() (*bleve.IndexMapping, error) {
var err error
// Create the index mapping, configure the analyzer, and set as default.
indexMapping := bleve.NewIndexMapping()
err = indexMapping.AddCustomTokenizer("ekanite_tk",
map[string]interface{}{
"regexp": `[^\W_]+`,
"type": regexp_tokenizer.Name,
})
if err != nil {
return nil, err
}
err = indexMapping.AddCustomAnalyzer("ekanite",
map[string]interface{}{
"type": custom_analyzer.Name,
"char_filters": []interface{}{},
"tokenizer": `ekanite_tk`,
"token_filters": []interface{}{`to_lower`},
})
if err != nil {
return nil, err
}
indexMapping.DefaultAnalyzer = "ekanite"
// Create field-specific mappings.
simpleJustIndexed := bleve.NewTextFieldMapping()
simpleJustIndexed.Store = false
simpleJustIndexed.IncludeInAll = true // XXX Move to false when using AST
simpleJustIndexed.IncludeTermVectors = false
timeJustIndexed := bleve.NewDateTimeFieldMapping()
timeJustIndexed.Store = false
timeJustIndexed.IncludeInAll = false
timeJustIndexed.IncludeTermVectors = false
articleMapping := bleve.NewDocumentMapping()
// Connect field mappings to fields.
articleMapping.AddFieldMappingsAt("Message", simpleJustIndexed)
articleMapping.AddFieldMappingsAt("ReferenceTime", timeJustIndexed)
articleMapping.AddFieldMappingsAt("ReceptionTime", timeJustIndexed)
// Tell the index about field mappings.
indexMapping.DefaultMapping = articleMapping
return indexMapping, nil
}
func bleveQueryFromExpr(expr query.Expr) (bleve.Query, error) {
if e, ok := expr.(*query.FieldExpr); ok {
return bleve.NewPhraseQuery([]string{e.Term}, e.Field), nil
} else if e, ok := expr.(*query.BinaryExpr); ok {
lhs, err := bleveQueryFromExpr(e.LHS)
if err != nil {
return nil, err
}
rhs, err := bleveQueryFromExpr(e.RHS)
if err != nil {
return nil, err
}
if e.Op == query.AND {
return bleve.NewConjunctionQuery([]bleve.Query{lhs, rhs}), nil
} else if e.Op == query.OR {
return bleve.NewDisjunctionQuery([]bleve.Query{lhs, rhs}), nil
}
}
return nil, nil
}