mgod

mgod is a MongoDB ODM specifically designed for Go. It provides a structured way to map Go models to MongoDB collections, simplifying database interactions in Go applications.

• Features
• Requirements
• Installation
• Basic Usage
• Motivation
• Future Scope
• Documentation
• Contribute
• License

Features

• Reuse existing Go structs to define models and perform Mongo operations.
• Automatic field transformation between Go and MongoDB using struct tags.
• Easily manage meta fields in models without cluttering Go structs.
• Supports union types, expanding data capabilities.
• Implement strict field requirements with struct tags for data integrity.
• Built-in support for multi-tenant systems.
• Wrapper around the official Mongo Go Driver.

Requirements

• Go 1.18 or higher.
• MongoDB 3.6 and higher.

Warning

For MongoDB version <4.4, please create the collection in MongoDB before creating an EntityMongoModel using mgod for the same. Refer to this MongoDB limitations for more information.

Installation

go get github.com/Lyearn/mgod

Basic Usage

Use existing MongoDB connection, or setup a new one to register a default database connection.

For existing database connection,

import "github.com/Lyearn/mgod"

func init() {
	// client is the MongoDB client obtained using Go Mongo Driver's Connect method.
	mgod.SetDefaultClient(client)
}

To setup a new connection,

import (
	"time"

	"github.com/Lyearn/mgod"
	"go.mongodb.org/mongo-driver/mongo/options"
)

func init() {
	// `cfg` is optional. Can rely on default configurations by providing `nil` value in argument.
	cfg := &mgod.ConnectionConfig{Timeout: 5 * time.Second}
	opts := options.Client().ApplyURI("mongodb://root:mgod123@localhost:27017")

	err := mgod.ConfigureDefaultClient(cfg, opts)
}

Add tags (wherever applicable) in existing struct (or define a new model).

type User struct {
	Name     string
	EmailID  string `bson:"emailId"`
	Age      *int32 `bson:",omitempty"`
	JoinedOn string `bson:"joinedOn" mgoType:"date"`
}

Use mgod to get the entity ODM.

import (
	"github.com/Lyearn/mgod"
	"github.com/Lyearn/mgod/schema/schemaopt"
)

model := User{}
dbName := "mgoddb"
collection := "users"

opts := mgod.NewEntityMongoModelOptions(dbName, collection, nil)
userModel, _ := mgod.NewEntityMongoModel(model, *opts)

Use the entity ODM to perform CRUD operations with ease.

Insert a new document.

joinedOn, _ := dateformatter.New(time.Now()).GetISOString()
userDoc := User{
	Name: "Gopher",
	EmailID: "gopher@mgod.com",
	JoinedOn: joinedOn,
}
user, _ := userModel.InsertOne(context.TODO(), userDoc)

Output:

{
	"_id": ObjectId("65697705d4cbed00e8aba717"),
	"name": "Gopher",
	"emailId": "gopher@mgod.com",
	"joinedOn": ISODate("2023-12-01T11:32:19.290Z"),
	"__v": 0
}

---

Find documents using model properties.

users, _ := userModel.Find(context.TODO(), bson.M{"name": userDoc.Name})

Output:

[]User{
	User{
		Name: "Gopher",
		EmailID: "gopher@mgod.com",
		JoinedOn: "2023-12-01T11:32:19.290Z",
	}
}

Motivation

Creating mgod was driven by the need to simplify MongoDB interactions while keeping one schema for all in Go. Traditionally, working with MongoDB in Go involved either using separate structs for database and service logic or manually converting service structs to MongoDB documents, a process that was both time-consuming and error-prone. This lack of integration often led to redundant coding, especially when dealing with union types or adding meta fields for each MongoDB operation.

Inspired by the easy interface of MongoDB handling using Mongoose and Typegoose libraries available in Node, mgod aims to streamline these processes. It offers a more integrated approach, reducing the need to duplicate code and enhancing type safety, making MongoDB operations more intuitive and efficient in Go.

Future Scope

The current version of mgod is a stable release. However, there are plans to add a lot more features like -

• Implement a setup step for storing a default Mongo connection, eliminating the need to pass it during EntityMongoModel creation.
• Provide support for transactions following the integration of default Mongo connection logic.
• Enable functionality to opt out of the default conversion of date fields to ISOString format.
• Develop easy to use wrapper functions around MongoDB Aggregation operation.
• Introduce automatic MongoDB collection selection based on Go struct names as a default behavior.
• Add test cases to improve code coverage.

If you have any interesting feature requests, feel free to open an issue on GitHub issue tracker. We will be more than happy to discuss that!

Documentation

For user facing documentation, check out docs.

Contribute

For contribution guidelines, check out CONTRIBUTING.

License

mgod is licensed under the MIT License.