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/
search.go
192 lines (154 loc) · 4.68 KB
/
search.go
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package search
import (
"context"
"log"
"sync"
"github.com/ardaguclu/ssearch/server/internal/rabinkarp"
"github.com/aws/aws-sdk-go/service/s3/s3manager"
"github.com/aws/aws-sdk-go/aws/endpoints"
"github.com/aws/aws-sdk-go/aws"
"github.com/aws/aws-sdk-go/aws/credentials"
"github.com/aws/aws-sdk-go/aws/request"
"github.com/aws/aws-sdk-go/aws/session"
"github.com/aws/aws-sdk-go/service/s3"
)
const (
S3LocalstackEndpoint = "http://localhost:4572"
MaxAllowedFileSize = int64(500 << (10 * 2))
S3DownloadPartSize = 64 << (10 * 2)
MaxObjectSizePerRequest = 1000
)
// S stores aws session specific details.
type S struct {
Env string
}
// SReq stores request informations and being used for paramteter binding.
type SReq struct {
Bucket string `form:"bucket" binding:"required"`
Text string `form:"filter" binding:"required"`
ResultCount int `form:"result-count" binding:"required"`
Region string `form:"region" binding:"required"`
StartDate int64 `form:"start"`
EndDate int64 `form:"end"`
}
// NewS returns S object which will be used for S3 access.
func NewS(env string) *S {
return &S{
Env: env,
}
}
// GetBuckets returns bucket list belongs to the current session.
func (s *S) GetBuckets(ctx context.Context, region string) ([]string, error) {
c := s3.New(s.newSession(region))
lbi := &s3.ListBucketsInput{}
lbo, err := c.ListBucketsWithContext(ctx, lbi, request.WithLogLevel(aws.LogDebugWithHTTPBody))
if err != nil {
return nil, err
}
var buckets []string
for _, b := range lbo.Buckets {
buckets = append(buckets, *b.Name)
}
return buckets, nil
}
// Start starts search process with the given parameters.
func (s *S) Start(ctx context.Context, req *SReq) ([]s3.Object, error) {
sess := s.newSession(req.Region)
c := s3.New(sess)
downloader := s3manager.NewDownloader(sess, func(d *s3manager.Downloader) { d.PartSize = S3DownloadPartSize })
head := &s3.HeadBucketInput{
Bucket: aws.String(req.Bucket),
}
_, err := c.HeadBucketWithContext(ctx, head, request.WithLogLevel(aws.LogDebugWithHTTPBody))
if err != nil {
return nil, err
}
loi := &s3.ListObjectsV2Input{
Bucket: aws.String(req.Bucket),
ContinuationToken: nil,
MaxKeys: aws.Int64(MaxObjectSizePerRequest),
}
var result []s3.Object
err = c.ListObjectsV2PagesWithContext(ctx, loi,
func(page *s3.ListObjectsV2Output, lastPage bool) bool {
s := s.search(ctx, page.Contents, *req, downloader)
if s != nil {
result = append(result, s...)
}
return lastPage || len(result) < req.ResultCount
})
if err != nil {
return nil, err
}
return result, nil
}
// search executes search operation concurrently within the batch object files and
// determines being found or not.
func (s *S) search(ctx context.Context, contents []*s3.Object, req SReq, downloader *s3manager.Downloader) []s3.Object {
var res []s3.Object
var wg sync.WaitGroup
var lock sync.Mutex
for _, c := range contents {
if req.EndDate > req.StartDate {
if req.StartDate != 0 && req.StartDate > c.LastModified.Unix() {
continue
}
if req.EndDate != 0 && req.EndDate < c.LastModified.Unix() {
continue
}
}
if *c.Size > MaxAllowedFileSize {
continue
}
wg.Add(1)
go func(ctx context.Context, obj s3.Object, d *s3manager.Downloader) {
defer wg.Done()
if s.found(ctx, req.Bucket, *obj.Key, req.Text, *obj.Size, d) {
lock.Lock()
defer lock.Unlock()
res = append(res, obj)
}
}(ctx, *c, downloader)
}
wg.Wait()
return res
}
// found is used for core search algorithm being implemented,
// it is designed for best performance. Since bucket in the S3 service expectedly stores huge amount of
// files.
func (s *S) found(ctx context.Context, bucket string, key string, searchText string, size int64, downloader *s3manager.Downloader) bool {
content := aws.NewWriteAtBuffer(make([]byte, size))
_, err := downloader.DownloadWithContext(ctx,
content,
&s3.GetObjectInput{
Bucket: aws.String(bucket),
Key: aws.String(key),
})
if err != nil {
log.Println("error occured ", err)
return false
}
result := content.Bytes()
rk := rabinkarp.New(searchText)
for _, c := range result {
if found := rk.SearchNextChar(c); found == true {
return true
}
}
return false
}
func (s *S) newSession(region string) *session.Session {
var sess *session.Session
if s.Env == "dev" {
sess = session.Must(session.NewSession(&aws.Config{
Credentials: credentials.NewStaticCredentials("foo", "var", ""),
Endpoint: aws.String(S3LocalstackEndpoint),
Region: aws.String(endpoints.EuWest1RegionID),
}))
} else {
sess = session.Must(session.NewSession(&aws.Config{
Region: aws.String(region)},
))
}
return sess
}