forked from couchbase/cbgt
/
main_uuid.go
52 lines (48 loc) · 1.76 KB
/
main_uuid.go
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// Copyright (c) 2015 Couchbase, Inc.
// 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 cmd
import (
"fmt"
"io/ioutil"
"os"
"strings"
"github.com/couchbase/cbgt"
log "github.com/couchbase/clog"
)
// MainUUID is a helper function for cmd-line tool developers, that
// reuses a previous "baseName.uuid" file from the dataDir if it
// exists, or generates a brand new UUID (and persists it).
func MainUUID(baseName, dataDir string) (string, error) {
uuid := cbgt.NewUUID()
uuidPath := dataDir + string(os.PathSeparator) + baseName + ".uuid"
uuidBuf, err := ioutil.ReadFile(uuidPath)
if err == nil {
uuid = strings.TrimSpace(string(uuidBuf))
if uuid == "" {
return "", fmt.Errorf("error: could not parse uuidPath: %s",
uuidPath)
}
log.Printf("main: manager uuid: %s", uuid)
log.Printf("main: manager uuid was reloaded")
} else {
log.Printf("main: manager uuid: %s", uuid)
log.Printf("main: manager uuid was generated")
}
err = ioutil.WriteFile(uuidPath, []byte(uuid), 0600)
if err != nil {
return "", fmt.Errorf("error: could not write uuidPath: %s\n"+
" Please check that your -data/-dataDir parameter (%q)\n"+
" is to a writable directory where %s can store\n"+
" index data.",
uuidPath, dataDir, baseName)
}
return uuid, nil
}