mongo

README

go-mongo

A library exposing an implementation of mongodb/mongo-go-driver.

You can configure the client URL and start interacting with the mongo db database without worrying about managing database connections. Every endpoint instantiates a database client and is independent of each other. Every endpoint can also be worked on a pool of go routines bringing concurrency benefits.

What is MongoDB?

MongoDB is a document based database service. It has a cloud-oriented product called MongoDB Atlas which handles the replication strategy without external effort. The schema is not required to be defined as the documents can contain anything.

Learning outcomes

• Configure Mongo DB Atlas database using the client url.
• Write, Update and Delete mongo document object using identifiers, wherever applicable.
• Filtering and sorting documents to a cursor response.
• Parsing a list response using a document cursor.

Installation

The recommended way to get started using the MongoDB Go driver is by using go modules to install the dependency in your project. This can be done either by importing packages from go-mongo and having the build step install the dependency or by explicitly running

go get github.com/atulanand206/go-mongo

Pre-requisites

• Mongo Client URL should be configured for the cluster of your choice.
• Database and Collection must be created on the database.

How to implement

• Define the required variables in the environment

mongoClientId := os.Getenv("MONGO_CLIENT_ID")
database = os.Getenv("DATABASE")
collection = os.Getenv("MONGO_COLLECTION")

• Configure the client before using any of the endpoints.

mongo.ConfigureMongoClient(mongoClientId)

Examples of bson documents

• bson.D: Convert an object to an ordered representation a bson document.

document, err := mongo.Document(&object)
if err != nil {
    log.Print(err)
    return
}

• bson.M: An unordered representation of a bson document.

filter := bson.M{"name": name}

• FindOptions: Object used for specifying sort and additional criteria.

opts := options.Find()
opts.SetSort(bson.D{primitive.E{Key: "rating", Value: -1}})

• Please refer to the bson documentation for information on the usage of the documents.

Examples of endpoints

• Write a document to the mongo collection.

mongo.Write(database, collection, *document)

• Update a document in the mongo collection based on filter criteria.

mongo.Update(database, collection, filter, *document)

• Delete a document from the mongo collection based on filter criteria.

mongo.Delete(database, collection, filter, *document)

• Find documents based on filters and options. The decoding depends on the actual definition of the object and hence required with the implementation.

cursor, err := mongo.Find(database, collection, filter, opts)
for cursor.Next(context.Background()) {
    var object Object
    err := cursor.Decode(&object)
    if err != nil {
        log.Print(err)
        return
    }
    response = append(response, object)
}

• Find a document based on filters and decode to object. First item is returned if multiple documents match the criteria.

response := mongo.FindOne(database, collection, filter)
var object Object
if err = response.Decode(&object); err != nil {
    log.Print(err)
    return
}

Author

• Atul Anand

License

The MongoDB Go Driver is licensed under the MIT License.

Documentation

Index

• func Document(request interface{}) (doc bson.M, err error)
• type DB
  • func (db *DB) Create(request interface{}, collection string) (err error)
  • func (db *DB) CreateCollection(collection string) error
  • func (db *DB) CreateMany(request []interface{}, collection string) (err error)
  • func (db *DB) DecodeRaw(cursor *mg.Cursor) (documents []bson.Raw, err error)
  • func (db *DB) Delete(collection string, identifier bson.M) (result *mg.DeleteResult, err error)
  • func (db *DB) Find(collection string, filters bson.M, findOptions *options.FindOptions) (result []bson.Raw, err error)
  • func (db *DB) FindOne(collection string, filters bson.M, findOptions *options.FindOneOptions) (result bson.Raw, err error)
  • func (db *DB) Update(collection string, identifier bson.M, doc interface{}) (result *mg.UpdateResult, err error)
• type DBConn
  • func NewDb(dbName string) DBConn
  • func NewMockDb() DBConn
• type MockDB
  • func (db *MockDB) Create(request interface{}, collection string) (err error)
  • func (db *MockDB) CreateCollection(collection string) error
  • func (db *MockDB) CreateMany(request []interface{}, collection string) (err error)
  • func (db *MockDB) Delete(collection string, identifier bson.M) (result *mg.DeleteResult, err error)
  • func (db *MockDB) Find(collection string, filters bson.M, findOptions *options.FindOptions) (results []bson.Raw, err error)
  • func (db *MockDB) FindOne(collection string, filters bson.M, findOptions *options.FindOneOptions) (result bson.Raw, err error)
  • func (db *MockDB) Update(collection string, identifier bson.M, v interface{}) (result *mg.UpdateResult, err error)
• type MongoClient
  • func NewMongoClient(url string, dbName string) *MongoClient
  • func (mongoClient *MongoClient) CreateCollection(collection string, options *options.CreateCollectionOptions) error
  • func (mongoClient *MongoClient) CreateCollections(collections []string) error
  • func (mongoClient *MongoClient) Delete(collection string, identifier bson.M) (*mongo.DeleteResult, error)
  • func (mongoClient *MongoClient) Disconnect()
  • func (mongoClient *MongoClient) Document(v interface{}) (doc *bson.D, err error)
  • func (mongoClient *MongoClient) DropCollections(collections []string) error
  • func (mongoClient *MongoClient) Find(collection string, filter bson.M, options *options.FindOptions) (*mongo.Cursor, error)
  • func (mongoClient *MongoClient) FindOne(collection string, filter bson.M, options *options.FindOneOptions) *mongo.SingleResult
  • func (mongoClient *MongoClient) GetMongoClient(clientUrl string) *mongo.Client
  • func (mongoClient *MongoClient) Update(collection string, identifier bson.M, change bson.D) (*mongo.UpdateResult, error)
  • func (mongoClient *MongoClient) Write(collection string, doc bson.D) (*mongo.InsertOneResult, error)
  • func (mongoClient *MongoClient) WriteMany(collection string, doc []interface{}) (*mongo.InsertManyResult, error)

Functions

func Document

func Document(request interface{}) (doc bson.M, err error)

Types

type DB

type DB struct {
	// contains filtered or unexported fields
}

func (*DB) Create

func (db *DB) Create(request interface{}, collection string) (err error)

func (*DB) CreateCollection

func (db *DB) CreateCollection(collection string) error

func (*DB) CreateMany

func (db *DB) CreateMany(request []interface{}, collection string) (err error)

func (*DB) DecodeRaw

func (db *DB) DecodeRaw(cursor *mg.Cursor) (documents []bson.Raw, err error)

func (*DB) Delete

func (db *DB) Delete(collection string, identifier bson.M) (result *mg.DeleteResult, err error)

func (*DB) Find

func (db *DB) Find(collection string, filters bson.M, findOptions *options.FindOptions) (result []bson.Raw, err error)

func (*DB) FindOne

func (db *DB) FindOne(collection string, filters bson.M, findOptions *options.FindOneOptions) (result bson.Raw, err error)

func (*DB) Update

func (db *DB) Update(collection string, identifier bson.M, doc interface{}) (result *mg.UpdateResult, err error)

type DBConn

type DBConn interface {
	CreateCollection(collection string) error
	Create(request interface{}, collection string) (err error)
	CreateMany(request []interface{}, collection string) (err error)
	FindOne(collection string, filters bson.M, findOptions *options.FindOneOptions) (result bson.Raw, err error)
	Find(collection string, filters bson.M, findOptions *options.FindOptions) (result []bson.Raw, err error)
	Delete(collection string, identifier bson.M) (result *mg.DeleteResult, err error)
	Update(collection string, identifier bson.M, doc interface{}) (result *mg.UpdateResult, err error)
}

func NewDb

func NewDb(dbName string) DBConn

func NewMockDb

func NewMockDb() DBConn

type MockDB

type MockDB struct {
	Data map[string]map[interface{}]interface{}
}

func (*MockDB) Create

func (db *MockDB) Create(request interface{}, collection string) (err error)

func (*MockDB) CreateCollection

func (db *MockDB) CreateCollection(collection string) error

func (*MockDB) CreateMany

func (db *MockDB) CreateMany(request []interface{}, collection string) (err error)

func (*MockDB) Delete

func (db *MockDB) Delete(collection string, identifier bson.M) (result *mg.DeleteResult, err error)

func (*MockDB) Find

func (db *MockDB) Find(collection string, filters bson.M, findOptions *options.FindOptions) (results []bson.Raw, err error)

func (*MockDB) FindOne

func (db *MockDB) FindOne(collection string, filters bson.M, findOptions *options.FindOneOptions) (result bson.Raw, err error)

func (*MockDB) Update

func (db *MockDB) Update(collection string, identifier bson.M, v interface{}) (result *mg.UpdateResult, err error)

type MongoClient

type MongoClient struct {
	// contains filtered or unexported fields
}

func NewMongoClient

func NewMongoClient(url string, dbName string) *MongoClient

func (*MongoClient) CreateCollection

func (mongoClient *MongoClient) CreateCollection(collection string, options *options.CreateCollectionOptions) error

func (*MongoClient) CreateCollections

func (mongoClient *MongoClient) CreateCollections(collections []string) error

Creates collections with given names

func (*MongoClient) Delete

func (mongoClient *MongoClient) Delete(collection string, identifier bson.M) (*mongo.DeleteResult, error)

Deletes the documents from the specified database and collection based on identifier filter. Returns the id of the document upon delete if one entry or the count information if many. If delete fails, returns an error otherwise. Client must be configured to use this endpoint.

func (*MongoClient) Disconnect

func (mongoClient *MongoClient) Disconnect()

func (*MongoClient) Document

func (mongoClient *MongoClient) Document(v interface{}) (doc *bson.D, err error)

Converts a struct to the bson document used for inserting document.

func (*MongoClient) DropCollections

func (mongoClient *MongoClient) DropCollections(collections []string) error

Drops collections with given names

func (*MongoClient) Find

func (mongoClient *MongoClient) Find(collection string, filter bson.M, options *options.FindOptions) (*mongo.Cursor, error)

Finds a cursor of the documents based on the filter and filter options from the specified database and collection. Returns the documents upon search and error otherwise. Client must be configured to use this endpoint.

func (*MongoClient) FindOne

func (mongoClient *MongoClient) FindOne(collection string, filter bson.M, options *options.FindOneOptions) *mongo.SingleResult

Finds a document based on the filter from the specified database and collection. Client must be configured to use this endpoint.

func (*MongoClient) GetMongoClient

func (mongoClient *MongoClient) GetMongoClient(clientUrl string) *mongo.Client

Returns the db client of the attached client url.

func (*MongoClient) Update

func (mongoClient *MongoClient) Update(collection string, identifier bson.M, change bson.D) (*mongo.UpdateResult, error)

Updates the documents to the specified database and collection based on identifier filter. Returns the id of the document upon update if one entry or the count information if many. If update fails, returns an error otherwise. Client must be configured to use this endpoint.

func (*MongoClient) Write

func (mongoClient *MongoClient) Write(collection string, doc bson.D) (*mongo.InsertOneResult, error)

Inserts a document to the specified database and collection. Returns the id of the document upon creation and error otherwise. Client must be configured to use this endpoint.

func (*MongoClient) WriteMany

func (mongoClient *MongoClient) WriteMany(collection string, doc []interface{}) (*mongo.InsertManyResult, error)

Inserts many documents to the specified database and collection. Returns the id of the documents upon creation and error otherwise. Client must be configured to use this endpoint.