Micro
Micro is a microservices toolkit. It simplifies writing and running distributed applications.
Checkout go-micro if you want to start writing services now.
Examples of how to write a service in ruby or python can be found in here
Checkout the roadmap
Overview
The goal of Micro is to provide a toolkit for microservice development and management. At the core, micro is simple and accessible enough that anyone can easily get started writing microservices. As you scale to hundreds of services, micro will provide the fundamental tools required to manage a microservice environment.
Features
Feature | Description |
---|---|
Discovery | Find running services |
Client | Query services via RPC |
Server | Listen and serve RPC requests |
Pub/Sub | Publish and subscribe to events |
API Gateway | Lightweight gateway/proxy. Convert http requests to rpc |
CLI | Command line interface |
Sidecar | Integrate any application into the Micro ecosystem |
Web UI | Simple 90s style dashboard to view and query services |
Architecture
Projects
Micro
Micro itself is the overarching toolkit and ecosystem
Go Micro
Go-micro is a pluggable Go framework for writing RPC based microservices. Go micro can be used standalone but fits into the bigger Micro ecosystem.
Go Platform
Go-platform provides higher level libraries and services that can be integrated into a go-micro service. Things like tracing, monitoring, dynamic configuration, etc. Again, pluggable like go-micro.
Go Plugins
Go-plugins provides a place for the community to provide their implementations of the interfaces. By default Micro will only support 1 or 2 implementations of each interface. Registries built on top of kubernetes, zookeeper, etc. Transport using http2, broker using kafka, etc.
micro-services.co
Micro-services.co is a place to share micro services.
Example Services
- geo-srv - A go-micro based geolocation tracking service using hailocab/go-geoindex
- geo-api - A HTTP API handler for geo location tracking and search
- greeter - Greeter client/server examples in Go, ruby and python
Getting Started
Install
$ go get github.com/micro/micro
Or via Docker
$ docker pull microhq/micro
Quick start
Run consul (default discovery mechanism)
$ go get github.com/hashicorp/consul
$ consul agent -server -bootstrap-expect 1 -data-dir /tmp/consul
Run the greeter example app
$ go get github.com/micro/micro/examples/greeter/server
$ server
List services
$ micro list services
consul
go.micro.srv.greeter
Get Service
$ micro get service go.micro.srv.greeter
go.micro.srv.greeter
Id Address Port Metadata
go.micro.srv.greeter-154a6487-7d7e-11e5-882a-34363b77bace [::] 57067
Endpoint: Say.Hello
Metadata: stream=false
Request:
{
name string
}
Response:
{
msg string
}
Endpoint: Debug.Health
Metadata: stream=false
Request: {}
Response:
{
status string
}
Query service
$ micro query go.micro.srv.greeter Say.Hello '{"name": "John"}'
{
"msg": "go.micro.srv.greeter-154a6487-7d7e-11e5-882a-34363b77bace: Hello John"
}
Read more on how to use Micro here
Learn how to write and run a microservice using Go-Micro here
Usage
NAME:
micro - A microservices toolchain
USAGE:
micro [global options] command [command options] [arguments...]
VERSION:
0.0.0
COMMANDS:
api Run the micro API
registry Query registry
query Query a service method using rpc
health Query the health of a service
list List items in registry
get Get item from registry
sidecar Run the micro sidecar
web Run the micro web app
help, h Shows a list of commands or help for one command
GLOBAL OPTIONS:
--server_name Name of the server. go.micro.srv.example [$MICRO_SERVER_NAME]
--server_id Id of the server. Auto-generated if not specified [$MICRO_SERVER_ID]
--server_address ":0" Bind address for the server. 127.0.0.1:8080 [$MICRO_SERVER_ADDRESS]
--server_metadata [--server_metadata option --server_metadata option] A list of key-value pairs defining metadata. version=1.0.0 [$MICRO_SERVER_METADATA]
--broker "http" Broker for pub/sub. http, nats, etc [$MICRO_BROKER]
--broker_address Comma-separated list of broker addresses [$MICRO_BROKER_ADDRESS]
--registry "consul" Registry for discovery. kubernetes, consul, etc [$MICRO_REGISTRY]
--registry_address Comma-separated list of registry addresses [$MICRO_REGISTRY_ADDRESS]
--transport "http" Transport mechanism used; http, rabbitmq, etc [$MICRO_TRANSPORT]
--transport_address Comma-separated list of transport addresses [$MICRO_TRANSPORT_ADDRESS]
--logtostderr log to standard error instead of files
--alsologtostderr log to standard error as well as files
--log_dir log files will be written to this directory instead of the default temporary directory
--stderrthreshold logs at or above this threshold go to stderr
-v log level for V logs
--vmodule comma-separated list of pattern=N settings for file-filtered logging
--log_backtrace_at when logging hits line file:N, emit a stack trace
--help, -h
Built in Web UI - -
About Microservices
Microservices is an architecture pattern used to decompose a single large application in to a smaller suite of services. Generally the goal is to create light weight services of 1000 lines of code or less. Each service alone provides a particular focused solution or set of solutions. These small services can be used as the foundational building blocks in the creation of a larger system.
The concept of microservices is not new, this is the reimagination of service orientied architecture but with an approach more holistically aligned with unix processes and pipes. For those of us with extensive experience in this field we're somewhat biased and feel this is an incredibly beneficial approach to system design at large and developer productivity.
Learn more about Microservices by watching Martin Fowler's presentation here or his blog post here.
Microservice Requirements
The foundation of a library enabling microservices is based around the following requirements:
- Server - an ability to define handlers and serve requests
- Client - an ability to make requests to another service
- Discovery - a mechanism by which to discover other services
These 3 components form the minimum requirements for microservices development. An ecosystem of libraries and tools can be created around them to provide a feature rich system however at the foundation only these 3 things are required to write services and communicate between them.
Server
The server is the core component which allows you to register request handlers and serve requests. Ideally it's transport agnostic so different transports such as http, rabbitmq, etc can be chosen. On start it should register itself with discovery system so other microservices know it exists and deregister when shutting down. The server should handle encoding/decoding incoming/outgoing requests, leaving the handlers to operate on the request/response types they expect.
Example interface:
server.New(name, options) - instantiate new server
server.Register(handler) - register a handler with the server
server.Start() - start
server.Stop() - stop
Client
Where the server allows you to serve requests, the client lets you make them to other servers. The client should support request/response and pub/sub. Part of the microservices world is event driven programming, taking action based on events, which is why pub/sub is a requirement of the client. It should also make use of the discovery system so requests can be made by service name.
Example interface:
client.Request(name, request) - Make a request to another server
client.Publish(topic, message) - Publish a message on a topic
client.Subscribe(topic, channel) - Subscribe to a topic
Discovery
The discovery system is really vital to microservices development. Any sort of communication between servers will first require locating it and then making the request. Discovery should support registration and retrieval of servers. It should optionally support a keepalive mechanism to remove stale servers.
Example interface:
discovery.Register(name, hostname, ...) - Register a server
discovery.Deregister(name, hostname, ...) - Deregister a server
discovery.Get(name) - Get the details for a server
discovery.List() - List all servers
Resources
- A Journey into Microservices
- A Journey into a Microservice World by Matt Heath (Slides)
- Microservices by Martin Fowler
- Microservices: Decomposing Applications for Deployability and Scalability by Chris Richardson (Slides)
- 4 reasons why microservices resonate by Neal Ford
Roadmap
Look here