Micro

Micro is an API first development platform. It addresses the core requirements for building services in the cloud by providing a set of APIs which act as the building blocks of any platform. Micro deals with the complexity of distributed systems and provides simpler programmable abstractions for developers to build on.

Overview

Architecture

Below are the core components that make up Micro

Server

Micro is built as a microkernel architecture. It abstracts away the complexity of the underlying infrastructure by providing a set of building block services composed as a single logical server for the end user to consume.

The server consists of the following services

Auth - Authentication and authorization out of the box using JWT tokens and rule based access control.
Broker - Ephemeral pubsub messaging for asynchronous communication and distributing notifications
Config - Dynamic configuration and secrets management for service level config without reload
Events - Event streaming with ordered messaging, replay from offsets and persistent storage
Network - service-to-service networking and control plane for all internal request traffic
Runtime - Service lifecycle and process management with support for source to running auto build
Registry - Centralised service discovery and API endpoint explorer with feature rich metadata
Store - Key-Value storage with TTL expiry and persistent crud to keep microservices stateless

API

The server embeds a HTTP API (on port 8080) which can be used to make requests as simple JSON. The API automatically maps HTTP Paths and POST requests to internal RPC service names and endpoints.

Proxy

Additionally there's a gRPC proxy (on port 8081) which used to make requests via the CLI or externally. The proxy is identity aware which means it can be used to gatekeep remote access to Micro running anywhere.

Framework

Micro comes with a built in Go framework for service based development. The framework lets you write services without piecing together endless lines of boilerplate code. Configured and initialised by default, import it and get started.

Command Line

The command line interface includes dynamic command mapping for all services running on the platform. It turns any service instantly into a CLI command along with flag parsing for inputs. Includes support for environments, namespaces, creating and running services, status info and logs.

Remote Environments

Micro bakes in the concept of Environments. Run your server locally for development and in the cloud for production, seamlessly switch between them using the CLI command micro env set [environment].

Install

From Source

make build

Prebuilt Binaries

Windows

powershell -Command "iwr -useb https://raw.githubusercontent.com/micro/micro/master/scripts/install.ps1 | iex"

Linux

wget -q  https://raw.githubusercontent.com/micro/micro/master/scripts/install.sh -O - | /bin/bash

MacOS

curl -fsSL https://raw.githubusercontent.com/micro/micro/master/scripts/install.sh | /bin/bash

Run the server

The server starts with a single command ready to use

micro server

Now go to localhost:8080 and make sure the output is something like {"version": "v3.10.1"}.

Usage

Set the environment e.g local

micro env set local

Login to Micro

Default username/password: admin/micro

$ micro login
Enter username: admin
Enter password:
Successfully logged in.

See what's running:

$ micro services
auth
broker
config
events
network
registry
runtime
store

Create a Service

Generate a service using the template

micro new helloworld

Output

Creating service helloworld

.
├── main.go
├── handler
│   └── helloworld.go
├── proto
│   └── helloworld.proto
├── Makefile
├── README.md
├── .gitignore
└── go.mod


download protoc zip packages (protoc-$VERSION-$PLATFORM.zip) and install:

visit https://github.com/protocolbuffers/protobuf/releases

compile the proto file helloworld.proto:

cd helloworld
make init
go mod vendor
make proto

Making changes

Edit the protobuf definition in proto/helloworld.proto and run make proto to recompile

Go to handler/helloworld.go to make changes to the response handler

type Helloworld struct{}

func New() *Helloworld {
        return &Helloworld{}
}

func (h *Helloworld) Call(ctx context.Context, req *pb.Request, rsp *pb.Response) error {
        rsp.Msg = "Hello " + req.Name
        return nil
}

Run the service

Run from local dir

micro run .

Or from a git url

micro run github.com/micro/services/helloworld

Check service status

$ micro status
NAME		VERSION	SOURCE					STATUS	BUILD	UPDATED	METADATA
helloworld	latest	github.com/micro/services/helloworld	running	n/a	4s ago	owner=admin, group=micro

View service logs

$ micro logs helloworld
2020-10-06 17:52:21  file=service/service.go:195 level=info Starting [service] helloworld
2020-10-06 17:52:21  file=grpc/grpc.go:902 level=info Server [grpc] Listening on [::]:33975
2020-10-06 17:52:21  file=grpc/grpc.go:732 level=info Registry [service] Registering node: helloworld-67627b23-3336-4b92-a032-09d8d13ecf95

Call via CLI

$ micro helloworld call --name=Jane
{
	"msg": "Hello Jane"
}

Call via API

curl "http://localhost:8080/helloworld/Call?name=John"

Call via RPC

An RPC client is used within a service and must be run by micro

package main

import (
	"context"
	"fmt"
	"time"

	"micro.dev/v4/service"
	pb "github.com/micro/services/helloworld/proto"
)

func callService(hw pb.HelloworldService) {
	for {
		// call an endpoint on the service
		rsp, err := hw.Call(context.Background(), &pb.CallRequest{
			Name: "John",
		})
		if err != nil {
			fmt.Println("Error calling helloworld: ", err)
			return
		}

		// print the response
		fmt.Println("Response: ", rsp.Message)

		time.Sleep(time.Second)
	}
}

func main() {
	// create and initialise a new service
	srv := service.New(
		service.Name("caller"),
	)

	// new helloworld client
	hw := pb.NewHelloworldService("helloworld", srv.Client())
	
	// run the client caller
	go callService(hw)
	
	// run the service
	service.Run()
}

Run it

micro run .

Call via Go

Get your user token

export TOKEN=`micro user token`

Call helloworld

package main

import (
    "fmt"
    "os"

    "github.com/micro/micro-go"
)

type Request struct {
	Name string `json:"name"`
}

type Response struct {
	Msg string `json:"msg"`
}

func main() {
	token := os.Getenv("TOKEN")
	c := micro.NewClient(nil)

	// set your api token
	c.SetToken(token)

   	req := &Request{
		Name: "John",
	}
	
	var rsp Response

	if err := c.Call("helloworld", "Call", req, &rsp); err != nil {
		fmt.Println(err)
		return
	}
	
	fmt.Println(rsp)
}