foundationdb/recipes/go-recipes/blob.go

103 lines
2.3 KiB
Go

/*
* blob.go
*
* This source file is part of the FoundationDB open source project
*
* Copyright 2013-2018 Apple Inc. and the FoundationDB project authors
*
* 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 main
import (
"fmt"
"github.com/apple/foundationdb/bindings/go/src/fdb"
"github.com/apple/foundationdb/bindings/go/src/fdb/directory"
"github.com/apple/foundationdb/bindings/go/src/fdb/subspace"
"github.com/apple/foundationdb/bindings/go/src/fdb/tuple"
)
const CHUNK_SIZE int = 5
func write_blob(t fdb.Transactor, blob_subspace subspace.Subspace, blob []byte) (err error) {
_, err = t.Transact(func(tr fdb.Transaction) (interface{}, error) {
if len(blob) == 0 {
return nil, nil
}
for i := 0; i < len(blob); i += CHUNK_SIZE {
if i+CHUNK_SIZE <= len(blob) {
tr.Set(blob_subspace.Pack(tuple.Tuple{i}), blob[i:i+CHUNK_SIZE])
} else {
tr.Set(blob_subspace.Pack(tuple.Tuple{i}), blob[i:])
}
}
return nil, nil
})
return
}
func read_blob(t fdb.ReadTransactor, blob_subspace subspace.Subspace) ([]byte, error) {
blb, err := t.ReadTransact(func(rtr fdb.ReadTransaction) (interface{}, error) {
var blob []byte
ri := rtr.GetRange(blob_subspace, fdb.RangeOptions{}).Iterator()
for ri.Advance() {
kv := ri.MustGet()
blob = append(blob, rtr.Get(kv.Key).MustGet()...)
}
return blob, nil
})
if err != nil {
return nil, err
}
return blb.([]byte), nil
}
func main() {
fdb.MustAPIVersion(700)
db := fdb.MustOpenDefault()
blobdir, err := directory.CreateOrOpen(db, []string{"blobdir"}, nil)
if err != nil {
fmt.Println(err)
}
blobspace := blobdir.Sub("blob")
test := []byte("ABCDEFGHIJKLMNOPQRSTUVWXYZ")
write_blob(db, blobspace, test)
ret, e := read_blob(db, blobspace)
if e == nil {
fmt.Println(string(ret))
}
}