cart

package module

v0.0.0-...-119882a Latest Latest Go to latest Published: Jul 22, 2019 License: MIT Imports: 11 Imported by: 0

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Repository

github.com/cooldryplace/cart

README ¶

Cart

©Roberto Badillo

Why

Hey, people want to buy products.

Building this microservice to scale better.

How

Cut a piece from the monolith and serve chilled.

API documentation

Have to be generated. So I have generated a client with GoDoc. Client documentation

Package structure

The package structure is simple for a reason. Currently, this is a straightforward service, so almost everything is in a single package, where business logic, data storage, and API code is located in separate files. Later if service will become more complex, there will be a need for better granularity and code isolation. But for now, I feel like this is the right balance.

Future structure

In the future packages structure will be derived from domains, and not from the functionality that code provides. An example would be:

user
billing
auth

Not:

controller
service
dao

@rakyll Style guideline for Go packages

Other microservices

Carts rely on other microservices.

AuthZ: to check that the caller is allowed to access/modify Cart state.
Billing: to get prices.
Business Analytics: to submit Cart updates details and make conclusions.
Products: to get product details.

Some microservices rely on Cart.

Orders: to retrieve Cart state.
Users: to retrieve Cart(s) for User profile.

Testing

To run all tests: go test github.com/cooldryplace/cart/....

To skip integration tests: go test --short github.com/cooldryplace/cart/....

Missing Parts

The current integration test does not cover cases when storage or other dependency fails.

Metrics

Currently, only API and client metrics are implemented. This already allows measuring availability and latency. In the future, I can add more specific metrics that will not be used in SLO implementations but will be in dashboards. To pinpoint the root cause of a problem during incidents. So we alert based on SLIs, look at the dashboard, and know where and why it happens.

Tracing

Adding spans here and there will help to identify bottlenecks. I use Opencensus with Stackdriver exporter for this.

Limitations

The current DB schema does not allow us to shard data. FKs and autoincrement are in the way. The suggested next step is to handle constraints in the application code. Start using UUIDs.

Documentation ¶

Overview ¶

Package cart provides shopping cart functionality. It exposes gRPC API and uses SQL DB as storage.

Constants ¶

This section is empty.

Variables ¶

This section is empty.

Functions ¶

This section is empty.

Types ¶

type Cart ¶

type Cart struct {
	ID        int64
	UserID    int64
	Items     []LineItem
	CreatedAt time.Time
	UpdatedAt time.Time
}

Cart holds LineItems for User.

type Carts ¶

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

Carts contains all business logic realated to this microservice.

func New ¶

func New(s storage) *Carts

New builds and returns new instance of Carts that is ready for use.

func (*Carts) AddProduct ¶

func (c *Carts) AddProduct(ctx context.Context, cartID, productID int64, quantity uint32) error

AddProduct to a Cart.

func (*Carts) Cart ¶

func (c *Carts) Cart(ctx context.Context, id int64) (Cart, error)

Cart returns Cart with provided ID.

func (*Carts) Create ¶

func (c *Carts) Create(ctx context.Context, userID int64) (Cart, error)

Create Cart for a User.

func (*Carts) Delete ¶

func (c *Carts) Delete(ctx context.Context, cartID int64) error

Delete Cart by ID.

func (*Carts) DeleteProduct ¶

func (c *Carts) DeleteProduct(ctx context.Context, cartID, productID int64) error

DeleteProduct in a Cart.

func (*Carts) Empty ¶

func (c *Carts) Empty(ctx context.Context, cartID int64) error

Empty Cart removes all previously added items.

type LineItem ¶

type LineItem struct {
	ProductID int64
	Quantity  uint32
	CreatedAt time.Time
	UpdatedAt time.Time
}

LineItem represents single SKU and quantity.

type Server ¶

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

Server implements protobuf Carts service.

func NewServer ¶

func NewServer(c *Carts) *Server

NewServer returns Carts gRPC server.

func (*Server) AddProduct ¶

func (s *Server) AddProduct(ctx context.Context, req *proto.AddProductRequest) (*empty.Empty, error)

AddProduct to a Cart.

func (*Server) CreateCart ¶

func (s *Server) CreateCart(ctx context.Context, req *proto.CartCreateRequest) (*proto.CartResponse, error)

CreateCart for a User.

func (*Server) DelProduct ¶

func (s *Server) DelProduct(ctx context.Context, req *proto.DelProductRequest) (*empty.Empty, error)

DelProduct removes product from a Cart.

func (*Server) DeleteCart ¶

func (s *Server) DeleteCart(ctx context.Context, req *proto.CartDeleteRequest) (*empty.Empty, error)

DeleteCart with the matching ID.

func (*Server) EmptyCart ¶

func (s *Server) EmptyCart(ctx context.Context, req *proto.EmptyCartRequest) (*empty.Empty, error)

EmptyCart deletes all LineItems from a Cart.

func (*Server) GetCart ¶

func (s *Server) GetCart(ctx context.Context, req *proto.CartRequest) (*proto.CartResponse, error)

GetCart returns current Cart state.

type Storage ¶

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

func NewStorage ¶

func NewStorage(db *sql.DB) *Storage

func (*Storage) AddProduct ¶

func (s *Storage) AddProduct(ctx context.Context, cartID, productID int64, quantity uint32) error

func (*Storage) CartByID ¶

func (s *Storage) CartByID(ctx context.Context, id int64) (Cart, error)

func (*Storage) CreateCart ¶

func (s *Storage) CreateCart(ctx context.Context, cart Cart) (Cart, error)

func (*Storage) DeleteCart ¶

func (s *Storage) DeleteCart(ctx context.Context, cartID int64) error

func (*Storage) DeleteLineItems ¶

func (s *Storage) DeleteLineItems(ctx context.Context, cartID int64) error

func (*Storage) DeleteProduct ¶

func (s *Storage) DeleteProduct(ctx context.Context, cartID, productID int64) error

Source Files ¶

View all Source files

Directories ¶

Path	Synopsis
cmd
cart
cartclient

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