mongo-connection.go

package database

import (
	"context"
	"fmt"
	"time"

	"code.fbi.h-da.de/danet/gosdn/controller/config"
	"code.fbi.h-da.de/danet/gosdn/controller/store"
	"github.com/sirupsen/logrus"
	"go.mongodb.org/mongo-driver/mongo"
	"go.mongodb.org/mongo-driver/mongo/options"
)

const (
	// Timeout operations after N seconds.
	timeout = 5 * time.Second
	// DatabaseName is the name of the mongoDB database used.
	DatabaseName = "gosdn"

	connectionRetries = 60
	connectionTimeout = time.Second * 2
)

// Connect Retrieves a client to the MongoDB.
func Connect() (*mongo.Database, error) {
	mongoConnection := config.DatabaseConnection
	ctx, cancel := context.WithTimeout(context.Background(), timeout)
	defer cancel()

	client, err := mongo.Connect(ctx, options.Client().ApplyURI(mongoConnection))
	if err != nil {
		return nil, fmt.Errorf("failed to create client: %w", err)
	}

	// Force a connection to verify our connection string
	err = client.Ping(ctx, nil)
	if err != nil {
		return nil, fmt.Errorf("failed to connect to database: %w", err)
	}

	db := client.Database(DatabaseName)
	if db == nil {
		return nil, fmt.Errorf("can not connect to database %s", DatabaseName)
	}

	return db, nil
}

func GetDatabaseConnection() (*mongo.Database, error) {
	var db *mongo.Database

	storeMode := store.GetStoreMode()

	switch storeMode {
	case store.Database:
		for i := 0; i < connectionRetries; i++ {
			db, err := Connect()
			if err == nil {
				return db, nil
			}
			logrus.Errorf("could not connect to mongo with error: %s. Retrying in 2 seconds.", err.Error())
			time.Sleep(connectionTimeout)
		}

		return nil, fmt.Errorf("could not connect to mongo after %d retries", connectionRetries)

	default:
		return db, nil
	}
}