SDK for Tailslide

---

Installation

---

Install the Tailslide npm package with

• Node.js: npm install tailslide
• Go: go get github.com/tailslide-io/tailslide.go
• Python: pip install tailslide-sdk
• Node.js: gem install tailslide

Basic Usage

---

Instantiating and Initializing FlagManager

The FlagManagerclass is the entry point of this SDK. It is responsible for retrieving all the flag rulesets for a given app with its appId and creating new Toggler instances to handle toggling of feature flags within that app. To instantiate a FlagManager object, a user must provide a configuration object:

JavaScript

const FlagManager = require('tailslide');

const config = {
  natsServer: 'nats://localhost:4222',
  natsStream: 'flags_ruleset',
  appId: 1,
  userContext: '375d39e6-9c3f-4f58-80bd-e5960b710295',
  sdkKey: 'myToken',
  redisHost: 'http://localhost',
  redisPort: 6379,
};

const manager = new FlagManager(config);
await manager.initialize();

Python

import asyncio
from tailslide import FlagManager

config = {
    "nats_server": "nats://localhost:4222",
    "nats_stream": "flags_ruleset",
    "app_id": 1,
    "user_context": "375d39e6-9c3f-4f58-80bd-e5960b710295",
    "sdk_key": "myToken",
    "redis_host": "http://localhost",
    "redis_port": 6379,
}

async def main():
    manager = FlagManager(**config)
    await manager.initialize()

asyncio.run(main())

Ruby

require "async"
require('tailslide')

config = {
    nats_server: "nats://localhost:4222",
    nats_stream: "flags_ruleset",
    app_id: 1,
    user_context: "375d39e6-9c3f-4f58-80bd-e5960b710295",
    sdk_key: "myToken",
    redis_host: "http://localhost",
    redis_port: 6379,
}

Async do |task|
    manager = FlagManager.new(**config)
    manager.initialize_flags

end

Golang

import (
    tailslide "github.com/tailslide-io/tailslide.go"
)

func main(){
  config := tailslide.FlagManagerConfig{
    NatsServer:  "nats://localhost:4222",
    NatsStream:  "flags_ruleset",
    AppId:       "1",
    UserContext: "375d39e6-9c3f-4f58-80bd-e5960b710295",
    SdkKey:      "myToken",
    RedisHost:   "http://localhost",
    RedisPort:   "6379",
  }

  manager := tailslide.NewFlagManager(config)
  manager.InitializeFlags()
}

• natsServer is the NATS JetStream server address:port
• natsStream is the NATS JetStream’s stream name that stores all the apps and their flag rulesets
• appId is the ID number of the app the user wants to retrieve its flag ruleset from
• userContext is the UUID string that identifies the current user
• sdkKey is the SDK key for the Tailslide, it is used as a password for NATS JetStream token authentication
• redisHost is the address to the Redis database
• redisPort is the port number that the Redis database runs on

After instantiating a FlagManager, invoke the initialize method. This method connects the FlagManager instance to both NATS JetStream and Redis Timeseries, and asynchronously retrieves the latest and any new flag ruleset data.

---

Using Feature Flag with Toggler

Once the FlagManager is initialized, it can create a Toggler, with the newToggler method, for each feature flag that the developer wants to wrap the new and old features in. A Toggler’s isFlagActive method checks whether the flag with its flagName is active or not based on the flag ruleset. A Toggler’s isFlagActive method returns a boolean value, which can be used to evaluate whether a new feature should be used or not.

JavaScript

const flagConfig = {
  flagName: 'App 1 Flag 1',
};

const flagToggler = manager.newToggler(flagConfig);

if (flagToggler.isFlagActive()) {
  // call new feature here
} else {
  // call old feature here
}

Python

flag_config = {
    "flag_name": 'App 1 Flag 1',
}

flag_toggler = manager.new_toggler(flag_config)

if flag_toggler.is_flag_active():
    # call new feature here
else:
    # call old feature here

Ruby

flag_config = {
    flag_name: 'App 1 Flag 1',
}

flag_toggler = manager.new_toggler(flag_config)

if flag_toggler.is_flag_active
    # call new feature here
else
    # call old feature here
end

Golang

flagConfig := tailslide.TogglerConfig{
  FlagName: "App 1 Flag 1",
}

flagToggler, err := manager.NewToggler(flagConfig)
if flagToggler.IsFlagActive() {
  // call new feature here
} else {
  // call old feature here
}

---

Emitting Success or Failture

To use a Toggler instance to record successful or failed operations, call its emitSuccess or emitFailure methods:

JavaScript

if (successCondition) {
  await flagToggler.emitSuccess();
} else {
  await flagToggler.emitFailure();
}

Python

if successCondition:
    flag_toggler.emit_success()
else:
    flag_toggler.emit_failure()

Ruby

if successCondition
    flag_toggler.emit_success
else
    flag_toggler.emit_failure
end

Golang

if successCondition {
  flagToggler.EmitSuccess()
} else {
  flagToggler.EmitFailure()
}

Documentation

---

For language specific documentation, please see README files at the following links:

JavaScript: https://github.com/tailslide-io/tailslide.js

Ruby: https://github.com/tailslide-io/tailslide.rb

Python: https://github.com/tailslide-io/tailslide.py

Golang: https://github.com/tailslide-io/tailslide.go