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
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.
The overarching project github.com/micro is a microservice ecosystem which consists of a number of tools and libraries. Each of which can either be used totally independently, plugged into your architecture or combined as a whole to provide a completely distributed systems platform.
It currently consists of the following.
A pluggable Go client framework for writing microservices.
| Feature | Description |
|---|---|
| Registry | Service discovery |
| Client | RPC Client |
| Codec | Request/Response Encoding |
| Selector | Load balancing |
| Server | RPC Server |
| Broker | Asynchronous Messaging |
| Transport | Synchronous Messaging |
Entry points into the runtime.
| Feature | Description |
|---|---|
| API Gateway | Lightweight gateway/proxy. Convert http requests to rpc |
| CLI | Command line interface |
| Sidecar | HTTP proxy for non Go-micro apps |
| Web UI/Proxy | A visual way to view and query services |
Libraries to integrate into distributed systems.
| Feature | Description |
|---|---|
| auth | authentication and authorisation for users and services |
| config | dynamic configuration which is namespaced and versioned |
| db | distributed database abstraction |
| discovery | extends the go-micro registry to add heartbeating, etc |
| event | platform event publication, subscription and aggregation |
| kv | simply key value layered on memcached, etcd, consul |
| log | structured logging to stdout, logstash, fluentd, pubsub |
| monitor | add custom healthchecks measured with distributed systems in mind |
| metrics | instrumentation and collation of counters |
| router | global circuit breaking, load balancing, A/B testing |
| sync | distributed locking, leadership election, etc |
| trace | distributed tracing of request/response |
A complete runtime for managing microservices at scale. Where Micro provides the core essentials, the platform goes a step further and addresses every requirement for large scale distributed system deployments.
| Feature | Description |
|---|---|
| Auth | Authentication and authorization (Oauth2) |
| Config | Dynamic configuration |
| DB Proxy | RPC based database proxy |
| Discovery | Service discovery read layer cache |
| Events | Platform event aggregation |
| Monitoring | Monitoring for Status, Stats and Healthchecks |
| Routing | Global service load balancing |
| Tracing | Distributed tracing |
Plugins for go-micro and go-platform contributed by the community. Examples could include; registries built on top of Kubernetes, Zookeeper, etc. Transport using HTTP2, Zeromq, etc. Broker using Kafka, AWS SQS, etc.
Example plugins
| Plugin | Description |
|---|---|
| NATS | Synchronous transport with the NATS message bus |
| Etcd | Service discovery using etcd |
| BSON-RPC | Request/Response encoding using bson-rpc |
| Project | Description |
|---|---|
| greeter | A greeter service (includes Go, Ruby, Python examples) |
| geo-srv | Geolocation tracking service using hailocab/go-geoindex |
| geo-api | A HTTP API handler for geo location tracking and search |
| discovery-srv | A discovery in the micro platform |
| geocode-srv | A geocoding service using the Google Geocoding API |
| hailo-srv | A service for the hailo taxi service developer api |
| monitor-srv | A monitoring service for Micro services |
| place-srv | A microservice to store and retrieve places (includes Google Place Search API) |
| slack-srv | The slack bot API as a go-micro RPC service |
| trace-srv | A distributed tracing microservice in the realm of dapper, zipkin, etc |
| twitter-srv | A microservice for the twitter API |
| user-srv | A microservice for user management and authentication |
| Project | Description |
|---|---|
| Micro Dashboard | Dashboard for microservices toolchain micro |
Learn how to write and run a microservice using go-micro
$ go get github.com/micro/microOr via Docker
$ docker pull microhq/microRun consul (default discovery mechanism)
$ go get github.com/hashicorp/consul
$ consul agent -dev -advertise=127.0.0.1
Run the greeter example app
$ go get github.com/micro/micro/examples/greeter/server
$ serverList services
$ micro list services
consul
go.micro.srv.greeterGet 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 the Micro CLI
NAME:
micro - A microservices toolkit
USAGE:
micro [global options] command [command options] [arguments...]
VERSION:
latest
COMMANDS:
api Run the micro API
registry Query registry
query Query a service method using rpc
stream Query a service method using streaming rpc
health Query the health of a service
list List items in registry
register Register an item in the registry
deregister Deregister an item in the 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 [$MICRO_SERVER_NAME]
--server_version Version of the server. 1.1.0 [$MICRO_SERVER_VERSION]
--server_id Id of the server. Auto-generated if not specified [$MICRO_SERVER_ID]
--server_address Bind address for the server. 127.0.0.1:8080 [$MICRO_SERVER_ADDRESS]
--server_advertise Used instead of the server_address when registering with discovery. 127.0.0.1:8080 [$MICRO_SERVER_ADVERTISE]
--server_metadata [--server_metadata option --server_metadata option] A list of key-value pairs defining metadata. version=1.0.0 [$MICRO_SERVER_METADATA]
--broker Broker for pub/sub. http, nats, rabbitmq [$MICRO_BROKER]
--broker_address Comma-separated list of broker addresses [$MICRO_BROKER_ADDRESS]
--registry Registry for discovery. memory, consul, etcd, kubernetes [$MICRO_REGISTRY]
--registry_address Comma-separated list of registry addresses [$MICRO_REGISTRY_ADDRESS]
--selector Selector used to pick nodes for querying. random, roundrobin, blacklist [$MICRO_SELECTOR]
--transport Transport mechanism used; http, rabbitmq, nats [$MICRO_TRANSPORT]
--transport_address Comma-separated list of transport addresses [$MICRO_TRANSPORT_ADDRESS]
--logtostderr log to standard error instead of files
--alsologtostderr log to standard error as well as files
--log_dir log files will be written to this directory instead of the default temporary directory
--stderrthreshold logs at or above this threshold go to stderr
-v log level for V logs
--vmodule comma-separated list of pattern=N settings for file-filtered logging
--log_backtrace_at when logging hits line file:N, emit a stack trace
--enable_tls Enable TLS [$MICRO_ENABLE_TLS]
--tls_cert_file TLS Certificate file [$MICRO_TLS_CERT_File]
--tls_key_file TLS Key file [$MICRO_TLS_KEY_File]
--api_address Set the api address e.g 0.0.0.0:8080 [$MICRO_API_ADDRESS]
--proxy_address Proxy requests via the HTTP address specified [$MICRO_PROXY_ADDRESS]
--sidecar_address Set the sidecar address e.g 0.0.0.0:8081 [$MICRO_SIDECAR_ADDRESS]
--web_address Set the web UI address e.g 0.0.0.0:8082 [$MICRO_WEB_ADDRESS]
--register_ttl "0" Register TTL in seconds [$MICRO_REGISTER_TTL]
--register_interval "0" Register interval in seconds [$MICRO_REGISTER_INTERVAL]
--api_namespace Set the namespace used by the API e.g. com.example.api [$MICRO_API_NAMESPACE]
--web_namespace Set the namespace used by the Web proxy e.g. com.example.web [$MICRO_WEB_NAMESPACE]
--api_cors Comma separated whitelist of allowed origins for CORS [$MICRO_API_CORS]
--web_cors Comma separated whitelist of allowed origins for CORS [$MICRO_WEB_CORS]
--sidecar_cors Comma separated whitelist of allowed origins for CORS [$MICRO_SIDECAR_CORS]
--enable_stats Enable stats [$MICRO_ENABLE_STATS]
--help, -h show help
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.
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.
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
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
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
- 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