/
watertower.go
133 lines (121 loc) · 3.15 KB
/
watertower.go
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package watertower
import (
"context"
"errors"
"fmt"
"io"
"os"
"path/filepath"
"sync"
"github.com/future-architect/gocloudurls"
"gocloud.dev/docstore"
_ "gocloud.dev/pubsub/mempubsub"
)
type WaterTower struct {
storage Storage
close sync.Once
defaultLanguage string
}
type Option struct {
DocumentUrl string
CollectionOpener func(ctx context.Context, opt Option) (*docstore.Collection, error)
LocalFolder string
Index string
CounterConcurrency int
TitleScoreRatio float64
DefaultLanguage string
}
func DefaultCollectionOpener(ctx context.Context, opt Option) (*docstore.Collection, error) {
url, err := defaultCollectionURL(opt)
if err != nil {
return nil, fmt.Errorf("Can't parse document URL: %w", err)
}
collection, err := docstore.OpenCollection(ctx, url)
if err != nil {
return nil, fmt.Errorf("Can't open collection: %w", err)
}
return collection, nil
}
// DefaultCollectionURL returns collection URL. This function is for help message or debugging
func DefaultCollectionURL(opt ...Option) (string, error) {
option, err := initOpt(opt...)
if err != nil {
return "", err
}
if option.CollectionOpener == nil {
return defaultCollectionURL(option)
}
return "", errors.New("Can't generate collection URL for custom opener")
}
func defaultCollectionURL(opt Option) (string, error) {
var filename string
if opt.LocalFolder != "" {
filename = filepath.Join(opt.LocalFolder, "watertower.db")
}
if opt.Index == "" {
opt.Index = "index"
}
url, err := gocloudurls.NormalizeDocStoreURL(opt.DocumentUrl, gocloudurls.Option{
Collection: opt.Index,
KeyName: "id",
FileName: filename,
})
return url, err
}
func initOpt(opt ...Option) (Option, error) {
var option Option
if len(opt) > 0 {
option = opt[0]
}
if option.DocumentUrl == "" {
option.DocumentUrl = os.Getenv("WATERTOWER_DOCUMENT_URL")
}
if option.TitleScoreRatio == 0.0 {
option.TitleScoreRatio = 5.0
}
if option.CounterConcurrency == 0 {
option.CounterConcurrency = 5
}
return option, nil
}
// NewWaterTower initialize WaterTower instance
func NewWaterTower(ctx context.Context, opt ...Option) (*WaterTower, error) {
option, err := initOpt(opt...)
if err != nil {
return nil, err
}
result := &WaterTower{
defaultLanguage: option.DefaultLanguage,
}
if option.DocumentUrl != "" {
if option.CollectionOpener == nil && option.DocumentUrl != "" {
option.CollectionOpener = DefaultCollectionOpener
}
c, err := option.CollectionOpener(ctx, option)
if err != nil {
return nil, err
}
s, err := newDocstoreStorage(ctx, c, option.Index, option.CounterConcurrency)
if err != nil {
return nil, err
}
result.storage = s
} else {
result.storage = newLocalIndex()
}
go func() {
<-ctx.Done()
result.storage.Close()
}()
return result, nil
}
// Close closes document store connection. Some docstore (at least memdocstore) needs Close() to store file
func (wt *WaterTower) Close() (err error) {
return wt.storage.Close()
}
func (wt *WaterTower) WriteIndex(w io.Writer) error {
return wt.storage.WriteIndex(w)
}
func (wt *WaterTower) ReadIndex(w io.Reader) error {
return wt.storage.ReadIndex(w)
}