missy

README

MiSSy

MiSSy (Microservice Support System) is an SDK for creating REST services that talk to each other. It provides the following functionality:

Features

• Routing with gorrila/mux
• Logging
• Configuration with environment variables
• Monitoring with Prometheus
• /info /health

Roadmap

• Service discovery
• REST client
• Security

How to use it

Example for a simple hello world service

Create a .missy.yml config file in the root directory of your service with the following content

name: hello

# main.go

package main

import (
	"github.com/microdevs/missy/service"
	"net/http"
	"fmt"
)

func main() {
	s := service.New("hello")
	s.HandleFunc("/hello/{name}", HelloHandler).Methods("GET")
	s.HandleFunc("/json", JsonHandler).Methods("GET")
	s.Start()
}

func HelloHandler(w http.ResponseWriter, r *http.Request) {
	vars := service.Vars(r)
	w.Write([]byte(fmt.Sprintf("Hello %s", vars["name"])))
}

// marshalling example
type MyType struct {
	A int
	B string
}

func JsonHandler(w http.ResponseWriter, r *http.Request) {
	mytype := MyType{
		A: 123,
		B: "Hello world",
	}
	
	data.Marshal(w, r, mytype)
}

// response body {A:123,B:"Hello world"}

Run it:

go run main.go

Call the Endpoint:

curl "http://localhost:8088/hello/microdevs"

Get Prometheus Metrics (all metrics are exposed on 8090 as default). To change this please set METRICS_LISTEN_PORT env. var.:

curl http://localhost:8090/metrics

Get Info:

http://localhost:8090/info

Response:

Name hello
Uptime 14.504883092s

Get Health:

http://localhost:8090/health

Response:

OK

Messaging

Use messaging.Reader and messaging.Writer to subscribe and publish messages. It uses kafka underneath. Example usage:

Reader with brokers hosts, group-id and topic

reader := messaging.NewReader([]string{"localhost:9092"}, "group-id", "topic")
err := reader.Read(func(msg Message) error{
    // do something with msg
    
    // return nil or error (if commit should not happen)
})

// remember to close reader after use
defer reader.Close()

#####Dead letter queue

If you need to save messages that couldn't be processed, you have to use constructor NewReaderWithDLQ which takes name of DLQ topic as additional parameter.

#####Writer with brokers hosts and topic

writer := messaging.NewWriter([]string{"localhost:9092"}, "topic")
err := writer.Write([]byte("key"), []byte("value"))

// remember to close writer after use
defer writer.Close()