gkBoot

README

gkBoot

Build Status

Objective

The purpose of gkBoot is to organize, compartmentalize and wire a microservice with the least amount of boilerplate while providing devs an easier time in building a microservice.

The inspiration for this is mostly Spring Boot. I liked the look of the decoupled architecture and the adherence to a domain-oriented design pattern.

In gkBoot, I tried to capture much of that while still maintaining that which makes Go great. Hopefully you like it too.

Installation

Note: Please use go 1.18 for installation

go get github.com/yomiji/gkBoot@v1.0.0

Use

Note: Please check out tests for advanced or detailed use cases

Users of gkBoot are recommended to follow a pattern when creating their microservics. Generally speaking, everything is centered around the service wiring (which sit in main.go) and the service files (which sit in the service directory):

├── go.mod
├── go.sum
├── main.go
├── services
│   └── greeting
│       └── greetings.go
└── tests
    └── greeting
        └── greetings_test.go

In services/greeting/greetings.go:

package greeting
import (
    "context"
    "fmt"
    "strconv"
    "github.com/yomiji/gkBoot"
    "github.com/yomiji/gkBoot/request"
)

type Request struct {
	// the "header!" tag value indicates that the value is required to be in
	// the header with the alias indicating that it should be named Secret-Value
	SecretValue string `header:"Secret-Value" required:"true" json:"-"`
	// the "query" tag value indicates that the value of the object is found in
	// the request query params
	FirstName   string `query:"firstName" json:"firstName"`
	// the "path" tag value indicates that the value of the object is found in
	// the url request path
	Age         int    `path:"age" json:"age"`
}

func (r Request) Info() request.HttpRouteInfo {
	return request.HttpRouteInfo{
		Name:        "DemoRequest",
		Method:      request.GET,
		Path:        "/{age}/greetings",
		Description: "A typical greeting.",
	}
}

type Service struct {
	gkBoot.BasicService
}

type Response struct {
	Greeting string
}

func (s Service) Execute(ctx context.Context, request interface{}) (response interface{}, err error) {
	reqObj := request.(*Request)
	
	var age string
	
	if reqObj.Age == 0 {
		age = "old"
	} else {
		age = strconv.Itoa(reqObj.Age)
	}
	
	greeting := fmt.Sprintf("Hello, %s! You're %s!\n", reqObj.FirstName, age)
	
	return Response{Greeting:greeting}, nil
}

In main.go:

package main
import (
	"greeting"
    "github.com/yomiji/gkBoot"
)

func main() {
    // start an http service on localhost port 8080
    gkBoot.StartServer([]gkBoot.ServiceRequest{
        {
            Request: new(greeting.Request),
            Service: new(greeting.Service),
        },
    })
}

In a client:

package main
import (
	"greeting"
	"github.com/yomiji/gkBoot"
)

func main() {
    Request := &greeting.Request {
        SecretValue: "Hello!",
        FirstName: "Simon!",
        Age: 21,
    }
	
    Response := &greeting.Response{}
    
    gkBoot.DoRequest("http://localhost:8080", Request, Response)
    
    //Response contains "Hello, Simon! You're 21!"
}

Documentation

Index

• func APIValidationWrapper(srv service.Service) service.Service
• func DoGeneratedRequest[ResponseType any](r *http.Request, responseObj *ResponseType) error
• func DoRequest[RequestType request.HttpRequest, ResponseType any](baseUrl string, clientRequest RequestType, responseObj *ResponseType) error
• func GenerateClientRequest(baseUrl string, serviceRequest request.HttpRequest) (*http.Request, error)
• func GenerateRequestDecoder(obj request.HttpRequest) (kitDefaults.DecodeRequestFunc, error)
• func GenerateSpecification(requests []ServiceRequest, optionalReflector *openapi3.Reflector) (openapi3.Reflector, error)
• func MakeHandler(serviceRequests []ServiceRequest, option ...config.GkBootOption) (http.Handler, *config.BootConfig)
• func NewServiceBuilder(srv service.Service, option ...config.GkBootOption) *serviceBuilder
• func Start(serviceRequests []ServiceRequest, option ...config.GkBootOption) (*http.Server, <-chan struct{})
• func StartServer(serviceRequests []ServiceRequest, option ...config.GkBootOption)
• func StartServerWithHandler(serviceRequests []ServiceRequest, option ...config.GkBootOption)
• func StartWithHandler(serviceRequests []ServiceRequest, option ...config.GkBootOption) (*http.Server, <-chan struct{})
• type BasicService
  • func (b BasicService) Execute(ctx context.Context, request interface{}) (response interface{}, err error)
• type BasicServiceWithDB
  • func (b BasicServiceWithDB) Execute(ctx context.Context, request interface{}) (response interface{}, err error)
• type HttpDecoder
• type JSONBody
• type ServiceRequest
• type SkipClientValidation
• type UsingSkipClientValidation
  • func (u UsingSkipClientValidation) SkipClientValidation()

Functions

func APIValidationWrapper

func APIValidationWrapper(srv service.Service) service.Service

func DoGeneratedRequest

func DoGeneratedRequest[ResponseType any](
	r *http.Request, responseObj *ResponseType,
) error

func DoRequest

func DoRequest[RequestType request.HttpRequest, ResponseType any](
	baseUrl string,
	clientRequest RequestType,
	responseObj *ResponseType,
) error

func GenerateClientRequest

func GenerateClientRequest(baseUrl string, serviceRequest request.HttpRequest) (*http.Request, error)

func GenerateRequestDecoder

func GenerateRequestDecoder(obj request.HttpRequest) (kitDefaults.DecodeRequestFunc, error)

GenerateRequestDecoder

When used in go-kit, generates a json decoder function that translates http requests to go concrete objects.

This reads 'request' tags in a concrete object to perform transformations from the relative http request parts to the given field in the result object. The 'request' tag may be applied to a field of type bool, string, int, int8, int16, int32, int64, float32, float64, complex64, complex128 or a slice of any of these (the relative part of the request must list slice values separated by comma).

The 'request' tag itself may be structured thus:

	type ConcreteObject struct {
	  Value   string           `request:"header"`                     // find in headers with name "Value"
	  MyInt   int              `request:"header" alias:"New-Integer"` // "New-Integer" in headers not "MyInt"
   MyBool  bool             `request:"query" json:"myBool"`        // "myBool" in the query params of request
	  MyFloat float32          `request:"query!"`                     // query param must be present as "MyFloat"
	  Body    CustomBodyStruct `request:"form"`                       // json request body as an object (json.Unmarshal)
	}

Note that this function will look for the corresponding field values using the following naming hierarchy:

alias -> json -> field name (exported)

This function will skip over unexported fields

The resulting decoder function always returns a pointer to a new instantiation of the 'obj' argument.

The obj argument may be a reference or a value type

func GenerateSpecification

func GenerateSpecification(requests []ServiceRequest, optionalReflector *openapi3.Reflector) (
	openapi3.Reflector,
	error,
)

func MakeHandler

func MakeHandler(serviceRequests []ServiceRequest, option ...config.GkBootOption) (http.Handler, *config.BootConfig)

func NewServiceBuilder

func NewServiceBuilder(srv service.Service, option ...config.GkBootOption) *serviceBuilder

NewServiceBuilder

This will wire up a service-only object that can re-use logging wrappers established elsewhere while maintaining the REST Request-Service established pattern. The associated Mixin chains must be called to identify which functionality is wired in.

Unavailable config options (using the following will not do anything):

config.WithServiceDecorator
config.WithHttpServerOpts
config.WithHttpPort
config.WithRootPath
config.WithStrictAPI

func Start

func Start(serviceRequests []ServiceRequest, option ...config.GkBootOption) (*http.Server, <-chan struct{})

Start

Starts the http server for GkBoot. Returns the running http.Server and a blocking function that waits until a signal (syscall.SIGINT, syscall.SIGTERM, syscall.SIGALRM) is sent.

func StartServer

func StartServer(serviceRequests []ServiceRequest, option ...config.GkBootOption)

StartServer

Convenience method.

If the service and blocker of Start are unnecessary, this conveniently does all of that for us.

func StartServerWithHandler

func StartServerWithHandler(serviceRequests []ServiceRequest, option ...config.GkBootOption)

func StartWithHandler

func StartWithHandler(serviceRequests []ServiceRequest, option ...config.GkBootOption) (*http.Server, <-chan struct{})

Types

type BasicService

type BasicService struct {
	service.UsingConfig
}

BasicService

This is the typical service with no DB attached, with an associated Configuration set by WithCustomConfig

It is recommended to use config.WithCustomConfig on gkBoot.Start followed by implementing member Execute function of your struct

func (BasicService) Execute

func (b BasicService) Execute(ctx context.Context, request interface{}) (response interface{}, err error)

type BasicServiceWithDB

type BasicServiceWithDB struct {
	service.UsingConfig
	service.UsingDB
}

BasicServiceWithDB

This is the typical service with custom config and DB

It is recommended to use config.WithCustomConfig and config.WithDatabase on gkBoot.Start followed by implementing member Execute function of your struct

func (BasicServiceWithDB) Execute

func (b BasicServiceWithDB) Execute(ctx context.Context, request interface{}) (response interface{}, err error)

type HttpDecoder

type HttpDecoder interface {
	Decode(ctx context.Context, httpRequest *http.Request) (request interface{}, err error)
}

HttpDecoder

Objects that implement this interface will pass the defined function to the decoder part of the go-kit route definition

type JSONBody

type JSONBody struct{}

JSONBody

When embedded into a request, flags the request as a JSON body to allow for automatic decoding.

type ServiceRequest

type ServiceRequest struct {
	Request request.HttpRequest
	Service service.Service
}

ServiceRequest

The request and service provided in this structure are submitted to the Start functions. The requests, when called from the http client, will route to the associated service to execute the business logic of the Execute method.

type SkipClientValidation

type SkipClientValidation interface {
	SkipClientValidation()
}

type UsingSkipClientValidation

type UsingSkipClientValidation struct{}

func (UsingSkipClientValidation) SkipClientValidation

func (u UsingSkipClientValidation) SkipClientValidation()