make delete idempotent

fixes ipfs/go-datastore#104

go.mod

@@ -2,7 +2,6 @@ module github.com/ipfs/go-ds-s3
 
 require (
 	github.com/aws/aws-sdk-go v1.15.60
-	github.com/ipfs/go-datastore v0.0.5
+	github.com/ipfs/go-datastore v0.1.0
 	github.com/ipfs/go-ipfs v0.4.22
-	google.golang.org/appengine v1.4.0 // indirect
 )

go.sum

@@ -182,6 +182,8 @@ github.com/ipfs/go-datastore v0.0.3 h1:/eP3nMDmLzMJNoWSSYvEkmMTTrm9FFCN+JraP9Ndl
 github.com/ipfs/go-datastore v0.0.3/go.mod h1:d4KVXhMt913cLBEI/PXAy6ko+W7e9AhyAKBGh803qeE=
 github.com/ipfs/go-datastore v0.0.5 h1:q3OfiOZV5rlsK1H5V8benjeUApRfMGs4Mrhmr6NriQo=
 github.com/ipfs/go-datastore v0.0.5/go.mod h1:d4KVXhMt913cLBEI/PXAy6ko+W7e9AhyAKBGh803qeE=
+github.com/ipfs/go-datastore v0.1.0 h1:TOxI04l8CmO4zGtesENhzm4PwkFwJXY3rKiYaaMf9fI=
+github.com/ipfs/go-datastore v0.1.0/go.mod h1:d4KVXhMt913cLBEI/PXAy6ko+W7e9AhyAKBGh803qeE=
 github.com/ipfs/go-detect-race v0.0.1 h1:qX/xay2W3E4Q1U7d9lNs1sU9nvguX0a7319XbyQ6cOk=
 github.com/ipfs/go-detect-race v0.0.1/go.mod h1:8BNT7shDZPo99Q74BpGMK+4D8Mn4j46UU0LZ723meps=
 github.com/ipfs/go-ds-badger v0.0.2 h1:7ToQt7QByBhOTuZF2USMv+PGlMcBC7FW7FdgQ4FCsoo=

s3.go

@@ -141,7 +141,11 @@ func (s *S3Bucket) Delete(k ds.Key) error {
 		Bucket: aws.String(s.Bucket),
 		Key:    aws.String(s.s3Path(k.String())),
 	})
-	return parseError(err)
+	if isNotFound(err) {
+		// delete is idempotent
+		err = nil
+	}
+	return err
 }
 
 func (s *S3Bucket) Query(q dsq.Query) (dsq.Results, error) {
@@ -223,8 +227,13 @@ func (s *S3Bucket) s3Path(p string) string {
 	return path.Join(s.RootDirectory, p)
 }
 
+func isNotFound(err error) bool {
+	s3Err, ok := err.(awserr.Error)
+	return ok && s3Err.Code() == s3.ErrCodeNoSuchKey
+}
+
 func parseError(err error) error {
-	if s3Err, ok := err.(awserr.Error); ok && s3Err.Code() == s3.ErrCodeNoSuchKey {
+	if isNotFound(err) {
 		return ds.ErrNotFound
 	}
 	return err
@@ -336,12 +345,16 @@ func (b *s3Batch) newDeleteJob(objs []*s3.ObjectIdentifier) func() error {
 				Objects: objs,
 			},
 		})
-		if err != nil {
+		if err != nil && !isNotFound(err) {
 			return err
 		}
 
 		var errs []string
 		for _, err := range resp.Errors {
+			if err.Code != nil && *err.Code == s3.ErrCodeNoSuchKey {
+				// idempotent
+				continue
+			}
 			errs = append(errs, err.String())
 		}