database connection for go-mongo-driver medium article

db.go

package db

import (
        "context"
        "fmt"
        "log"
        "os"

        "go.mongodb.org/mongo-driver/mongo"
        "go.mongodb.org/mongo-driver/mongo/options"
)

var mongoClient *mongo.Client

// Datastore is a wrapper around mongo.Client.
type Datastore struct {
        Client       *mongo.Client
        DatabaseName string
}

// New creates a new mongo.Client
func New() *Datastore {
        databaseName, ok := os.LookupEnv("MONGO_DATABASE_NAME")
        if !ok {
                databaseName = "uptime"
        }
        mongoHost := os.Getenv("MONGO_HOST")
        mongoPass := os.Getenv("MONGO_INITDB_ROOT_PASSWORD")
        connString := fmt.Sprintf("mongodb://root:%s@%s:27017", mongoPass, mongoHost)
        if mongoClient == nil {
                client, err := mongo.NewClient(options.Client().ApplyURI(connString))
                if err != nil {
                        log.Fatal(err)
                }
                err = client.Connect(context.TODO())
                if err != nil {
                        log.Fatal(err)
                }

                mongoClient = client
        }

        return &Datastore{
                Client:       mongoClient,
                DatabaseName: databaseName,
        }
}