go_study/fabric-main/core/common/ccprovider/targzmetadataprovider.go

78 lines
1.9 KiB
Go

/*
# Copyright State Street Corp. All Rights Reserved.
#
# SPDX-License-Identifier: Apache-2.0
*/
package ccprovider
import (
"archive/tar"
"bytes"
"compress/gzip"
"io"
"strings"
)
// The targz metadata provider is reference for other providers (such as what CAR would
// implement). Currently it treats only statedb metadata but will be generalized in future
// to allow for arbitrary metadata to be packaged with the chaincode.
const (
ccPackageStatedbDir = "META-INF/statedb/"
)
type PersistenceAdapter func([]byte) ([]byte, error)
func (pa PersistenceAdapter) GetDBArtifacts(codePackage []byte) ([]byte, error) {
return pa(codePackage)
}
// MetadataAsTarEntries extracts metadata from a chaincode package
func MetadataAsTarEntries(code []byte) ([]byte, error) {
is := bytes.NewReader(code)
gr, err := gzip.NewReader(is)
if err != nil {
ccproviderLogger.Errorf("Failure opening codepackage gzip stream: %s", err)
return nil, err
}
statedbTarBuffer := bytes.NewBuffer(nil)
tw := tar.NewWriter(statedbTarBuffer)
tr := tar.NewReader(gr)
// For each file in the code package tar,
// add it to the statedb artifact tar if it has "statedb" in the path
for {
header, err := tr.Next()
if err == io.EOF {
// We only get here if there are no more entries to scan
break
}
if err != nil {
return nil, err
}
if !strings.HasPrefix(header.Name, ccPackageStatedbDir) {
continue
}
if err = tw.WriteHeader(header); err != nil {
ccproviderLogger.Error("Error adding header to statedb tar:", err, header.Name)
return nil, err
}
if _, err := io.Copy(tw, tr); err != nil {
ccproviderLogger.Error("Error copying file to statedb tar:", err, header.Name)
return nil, err
}
ccproviderLogger.Debug("Wrote file to statedb tar:", header.Name)
}
if err = tw.Close(); err != nil {
return nil, err
}
ccproviderLogger.Debug("Created metadata tar")
return statedbTarBuffer.Bytes(), nil
}