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// Copyright 2018 The LUCI 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
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// See the License for the specific language governing permissions and
// limitations under the License.
package bq
import (
var (
// defaultPrefix is a global value is used to populate a zero-value
// InsertIDGenerator.
defaultPrefix string
func init() {
t := time.Now().UnixNano()
defaultPrefix = fmt.Sprintf("%d:%d:%d", rand.Int(), os.Getpid(), t)
// InsertIDGenerator generates unique Insert IDs.
// BigQuery uses Insert IDs to deduplicate rows in the streaming insert buffer.
// The association between Insert ID and row persists only for the time the row
// is in the buffer.
// InsertIDGenerator is safe for concurrent use.
type InsertIDGenerator struct {
// Counter is an atomically-managed counter used to differentiate Insert
// IDs produced by the same process.
Counter int64
// Prefix should be able to uniquely identify this specific process,
// to differentiate Insert IDs produced by different processes.
// If empty, prefix will be derived from system and process specific
// properties.
Prefix string
// Generate returns a unique Insert ID.
func (id *InsertIDGenerator) Generate() string {
prefix := id.Prefix
if prefix == "" {
prefix = defaultPrefix
c := atomic.AddInt64(&id.Counter, 1)
return fmt.Sprintf("%s:%d", prefix, c)