/
google.go
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/
google.go
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// Licensed to Elasticsearch B.V. under one or more contributor
// license agreements. See the NOTICE file distributed with
// this work for additional information regarding copyright
// ownership. Elasticsearch B.V. licenses this file to you 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 storage
import (
"context"
"errors"
"fmt"
pathutil "path"
"cloud.google.com/go/storage"
)
// GCS Backend object storage manager
func GCS(client *storage.Client, bucket, prefix string) Backend {
return &gcsBackend{
client: client,
bucket: bucket,
prefix: prefix,
}
}
// -----------------------------------------------------------------------------
// googleGCSBackend is a storage backend for Google Cloud Storage
type gcsBackend struct {
client *storage.Client
bucket string
prefix string
}
// GetObject retrieves an object from Google Cloud Storage bucket, at prefix
func (b *gcsBackend) GetObject(ctx context.Context, path string) (*Object, error) {
// Check parameters
if b.client == nil {
return nil, errors.New("gcs: client is nil")
}
// Query gcs bucket
objectHandle := b.client.Bucket(b.bucket).Object(pathutil.Join(b.prefix, path))
if objectHandle == nil {
return nil, errors.New("gcs: unable to retrieve object reference")
}
// Retrieve object attributes
attrs, err := objectHandle.Attrs(ctx)
if err != nil {
return nil, fmt.Errorf("gcs: unable to retrieve object attribute: %w", err)
}
// Prepare content reader
rc, err := objectHandle.NewReader(ctx)
if err != nil {
return nil, fmt.Errorf("gcs: unable to initialie object reader: %w", err)
}
// Assemble response
var object Object
object.Path = path
object.Content = rc
object.LastModified = attrs.Updated
// No error
return &object, nil
}