mongo-sequence

Sequence implementation for mongodb. Unlike sql databases, mongodb doesn't have any built-in functionality to create sequence.

mongo-sequence provide sequence document on mongodb.

Installation

go get github.com/hendratommy/mongo-sequence

Examples

package sequence_test

import (
	"context"
	"fmt"
	"github.com/hendratommy/mongo-sequence/pkg/sequence"
	"go.mongodb.org/mongo-driver/mongo"
	"go.mongodb.org/mongo-driver/mongo/options"
	"os"
	"time"
)

func ExampleNextVal() {
	// create mongodb client
	client, err := mongo.NewClient(options.Client().ApplyURI(os.Getenv("MONGODB_URI")))
	if err != nil {
		panic(err)
	}
	if err = client.Connect(context.TODO()); err != nil {
		panic(err)
	}
	db := client.Database("myDB")

	// clean up test
    //defer func() {
    //	_ = db.Drop(context.TODO())
    //	_ = client.Disconnect(context.TODO())
    //}()

	// set `sequences` collection to use to store sequence records
	coll := db.Collection("sequences")
	// coll := db.Collection("mySequences")

	// set default sequence to use `sequences` collection
	sequence.SetupDefaultSequence(coll, 1*time.Second)

	// get next value from `DefaultSequenceName` sequence
	val, err := sequence.NextVal(sequence.DefaultSequenceName)
	if err != nil {
		panic(err)
	}
	fmt.Printf("value is: %d\n", val)
	val, err = sequence.NextVal(sequence.DefaultSequenceName)
	if err != nil {
		panic(err)
	}
	fmt.Printf("value is: %d\n", val)
	val, err = sequence.NextVal(sequence.DefaultSequenceName)
	if err != nil {
		panic(err)
	}
	fmt.Printf("value is: %d\n", val)

	// get next value from `orderSeq` sequence
	val, err = sequence.NextVal("orderSeq")
	if err != nil {
		panic(err)
	}
	fmt.Printf("value is: %d\n", val)

	// Output:
	// value is: 1
	// value is: 2
	// value is: 3
	// value is: 1
}

$ db.sequences.find();
{ "_id" : "defaultSeq", "value" : 4 }
{ "_id" : "orderSeq", "value" : 2 }

See examples for more details.