unleash-client-go

Unleash Client for Go. Read more about the Unleash project

Version 3.x of the client requires unleash-server v3.x or higher.

Go Version

The client is currently tested against Go 1.10.x and 1.13.x. These versions will be updated as new versions of Go are released.

The client may work on older versions of Go as well, but are not actively tested.

Getting started

1. Install unleash-client-go

To install the latest version of the client use:

go get github.com/Unleash/unleash-client-go/v3

If you are still using Unleash Server v2.x.x, then you should use:

go get github.com/Unleash/unleash-client-go

2. Initialize unleash

The easiest way to get started with Unleash is to initialize it early in your application code:

import (
	"github.com/Unleash/unleash-client-go/v3"
)

func init() {
	unleash.Initialize(
		unleash.WithListener(&unleash.DebugListener{}),
		unleash.WithAppName("my-application"),
		unleash.WithUrl("http://unleash.herokuapp.com/api/"),
		unleash.WithCustomHeaders(http.Header{"Authorization": {"<API token>"}}),
	)
}

3. Use unleash

After you have initialized the unleash-client you can easily check if a feature toggle is enabled or not.

unleash.IsEnabled("app.ToggleX")

4. Stop unleash

To shut down the client (turn off the polling) you can simply call the destroy-method. This is typically not required.

unleash.Close()

Built in activation strategies

The Go client comes with implementations for the built-in activation strategies provided by unleash.

• DefaultStrategy
• UserIdStrategy
• FlexibleRolloutStrategy
• GradualRolloutUserIdStrategy
• GradualRolloutSessionIdStrategy
• GradualRolloutRandomStrategy
• RemoteAddressStrategy
• ApplicationHostnameStrategy

Read more about the strategies in activation-strategy.md.

Unleash context

In order to use some of the common activation strategies you must provide a unleash-context. This client SDK allows you to send in the unleash context as part of the isEnabled call:

ctx := context.Context{
    UserId: "123",
    SessionId: "some-session-id",
    RemoteAddress: "127.0.0.1",
}

unleash.IsEnabled("someToggle", unleash.WithContext(ctx))

Caveat

This client uses go routines to report several events and doesn't drain the channel by default. So you need to either register a listener using WithListener or drain the channel "manually" (demonstrated in this example).

Development

Adding client specifications

In order to make sure the unleash clients uphold their contract, we have defined a set of client specifications that define this contract. These are used to make sure that each unleash client at any time adhere to the contract, and define a set of functionality that is core to unleash. You can view the client specifications here.

In order to make the tests run please do the following steps.

// in repository root
// testdata is gitignored
mkdir testdata
cd testdata
git clone https://github.com/Unleash/client-specification.git

Requirements:

• make
• golint (go get -u golang.org/x/lint/golint)

Run tests:

make

Run lint check:

make lint

Run code-style checks:(currently failing)

make strict-check

Run race-tests:

make test-all