Ruby Server SDK
Installation
If you are using Bundler, add the gem to your Gemfile from command line:
bundle add statsig
or directly include it in your Gemfile and run bundle install
:
gem "statsig", ">= X.Y.Z"
Check out the latest versions on https://rubygems.org/gems/statsig
Initialize the SDK
After installation, you will need to initialize the SDK using a Server Secret Key from the statsig console.
Do NOT embed your Server Secret Key in client-side applications, or expose it in any external-facing documents. However, if you accidentally expose it, you can create a new one in the Statsig console.
options
that allows you to pass in a StatsigOptions to customize the SDK.require 'statsig'Statsig.initialize('server-secret-key')
# Or, if you want to initialize with certain optionsoptions = StatsigOptions.new({'tier' => 'staging'}, network_timeout: 5)# And a callback when the initialization network request fails def error_callback(e) puts e end...Statsig.initialize('server-secret-key', options, method(:error_callback))
Initializing Statsig in a Rails Application
If your application is using Rails, you should initialize Statsig in config/initializers/statsig.rb
:
Statsig.initialize('server-secret-key', options)
Initializing Statsig when using Unicorn, Puma, Passenger, or Sidekiq
For Unicorn, you should initialize Statsig within an after_fork
hook in your unicorn.rb
config file:
after_fork do |server,worker| Statsig.initialize('server-secret-key', options)end
For Puma, you should initialize Statsig within an on_worker_boot
hook in your puma.rb
config file:
on_worker_boot do Statsig.initialize('server-secret-key', options)end
For Passenger, you should initialize Statsig in your config.ru
config file:
if defined?(PhusionPassenger) PhusionPassenger.on_event(:starting_worker_process) do |forked| Statsig.initialize('server-secret-key', options) endend
For Sidekiq, you should initialize Statsig in your sidekiq.rb
/server configuration file:
Sidekiq.configure_server do |config| config.on(:startup) do Statsig.initialize end config.on(:shutdown) do Statsig.shutdown endend
If you are using Rails in combination with any of the above, you should be sure to initialize using the specific process lifecycle hooks exposed by the respective tool. You can initialize in multiple places, which should ensure the SDK is fully usable including all background processing.
initialize
will perform a network request. After initialize
completes, virtually all SDK operations will be synchronous (See Evaluating Feature Gates in the Statsig SDK). The SDK will fetch updates from Statsig in the background, independently of your API calls.Working with the SDK
Checking a Feature Flag/Gate
Now that your SDK is initialized, let's fetch a Feature Gate. Feature Gates can be used to create logic branches in code that can be rolled out to different users from the Statsig Console. Gates are always CLOSED or OFF (think return false;
) by default.
From this point on, all APIs will require you to specify the user (see Statsig user) associated with the request. For example, check a gate for a certain user like this:
user = StatsigUser.new({'userID' => 'some_user_id'})if Statsig.check_gate(user, 'use_new_feature') # Gate is on, enable new featureelse # Gate is offend
Reading a Dynamic Config
Feature Gates can be very useful for simple on/off switches, with optional but advanced user targeting. However, if you want to be able send a different set of values (strings, numbers, and etc.) to your clients based on specific user attributes, e.g. country, Dynamic Configs can help you with that. The API is very similar to Feature Gates, but you get an entire json object you can configure on the server and you can fetch typed parameters from it. For example:
config = Statsig.get_config(user, 'awesome_product_details')# The 2nd parameter is the default value to be used in case the given parameter name does not exist on# the Dynamic Config object. This can happen when there is a typo, or when the user is offline and the# value has not been cached on the client.item_name = config.get('product_name', 'Awesome Product v1');price = config.get('price', 10.0);shouldDiscount = config.get('discount', false);# Or just get the whole json object backing this config if you preferjson = config.value
Getting an Layer/Experiment
Then we have Layers/Experiments, which you can use to run A/B/n experiments. We offer two APIs, but we recommend the use of layers to enable quicker iterations with parameter reuse.
# Values via getLayerlayer = Statsig.get_layer(user, "user_promo_experiments")title = layer.get("title", "Welcome to Statsig!")discount = layer.get("discount", 0.1)# or, via getExperimenttitle_exp = Statsig.get_experiment(user, "new_user_promo_title")price_exp = Statsig.get_experiment(user, "new_user_promo_price")title = title_exp.get("title", "Welcome to Statsig!")discount = price_exp.get("discount", 0.1)...price = msrp * (1 - discount)
We mentioned earlier that after calling initialize
most SDK APIs would run synchronously, so why are getConfig
and checkGate
asynchronous?
The main reason is that older versions of the SDK might not know how to interpret new types of gate conditions. In such cases the SDK will make an asynchronous call to our servers to fetch the result of a check. This can be resolved by upgrading the SDK, and we will warn you if this happens.
For more details, read our blog post about SDK evaluations. If you have any questions, please ask them in our Feedback Repository.
Logging an Event
Now that you have a Feature Gate or an Experiment set up, you may want to track some custom events and see how your new features or different experiment groups affect these events. This is super easy with Statsig - simply call the Log Event API and specify the user and event name to log; you additionally provide some value and/or an object of metadata to be logged together with the event:
Statsig.log_event( user, 'add_to_cart', 'SKU_12345', { 'price' => '9.99', 'item_name' => 'diet_coke_48_pack' })
Learn more about identifying users, group analytics, and best practices for logging events in the logging events guide.
Retrieving Feature Gate Metadata
In certain scenarios, you may need more information about a gate evaluation than just a boolean value. For additional metadata about the evaluation, use the Get Feature Gate API, which returns a FeatureGate object
Statsig User
When calling APIs that require a user, you should pass as much information as possible in order to take advantage of advanced gate and config conditions (like country or OS/browser level checks), and correctly measure impact of your experiments on your metrics/events. The userID
field is required because it's needed to provide a consistent experience for a given user (click here to understand further why it's important to always provide a userID).
Besides userID
, we also have email
, ip
, userAgent
, country
, locale
and appVersion
as top-level fields on StatsigUser. In addition, you can pass any key-value pairs in an object/dictionary to the custom
field and be able to create targeting based on them.
Note that while typing is lenient on the StatsigUser
object to allow you to pass in numbers, strings, arrays, objects, and potentially even enums or classes, the evaluation operators will only be able to operate on primitive types - mostly strings and numbers. While we attempt to smartly cast custom field types to match the operator, we cannot guarantee evaluation results for other types. For example, setting an array as a custom field will only ever be compared as a string - there is no operator to match a value in that array.
Private Attributes
Have sensitive user PII data that should not be logged? No problem, we have a solution for it! On the StatsigUser object we also have a field called privateAttributes
, which is a simple object/dictionary that you can use to set private user attributes. Any attribute set in privateAttributes
will only be used for evaluation/targeting, and removed from any logs before they are sent to Statsig server.
For example, if you have feature gates that should only pass for users with emails ending in "@statsig.com", but do not want to log your users' email addresses to Statsig, you can simply add the key-value pair { email: "my_user@statsig.com" }
to privateAttributes
on the user and that's it!
Statsig Options
You can specify optional parameters with options
when initializing.
- environment: Hash, default
nil
- a Hash you can use to set environment variables that apply to all of your users in the same session and will be used for targeting purposes.
- The most common usage is to set the "tier" (string), and have feature gates pass/fail for specific environments. The accepted values are "production", "staging" and "development", e.g.
StatsigOptions.New({ 'tier' => 'staging' })
.
- api_url_base string, default
"https://statsigapi.net/v1"
- The base url to use for network requests from the SDK
- rulesets_sync_interval: Number, default
10
- The interval to poll for changes to your gate and config definition changes
- idlists_sync_interval: Number, default
60
- The interval to poll for changes to id lists
- logging_interval_seconds: Number, default
60
- The default interval to flush logs to Statsig servers
- logging_max_buffer_size: Number, default
1000
, can be set lower but anything over 1000 will be dropped on the server- The maximum number of events to batch before flushing logs to the server
- local_mode: Boolean, default
false
- An option to restrict the sdk to not issue any network requests and only respond with default values (or local overrides)
- bootstrap_values: String, default nil
- a string that represents all rules for all feature gates, dynamic configs and experiments. It can be provided to bootstrap the Statsig server SDK at initialization in case your server runs into network issue or Statsig server is down temporarily.
- rules_updated_callback: function, default nil
- a callback function that's called whenever we have an update for the rules; it's called with a logical timestamp and a JSON string (used as is for bootstrapValues mentioned above). Note that as of v0.6.0, this will be called from a background thread that the SDK uses to update config values.
- data_store: IDataStore, default nil
- A data store with custom storage behavior for config specs. Can be used to bootstrap Statsig server (takes priority over
bootstrap_values
). Can also be used to continuously fetch updates in place of the Statsig network. See Data Stores.
- A data store with custom storage behavior for config specs. Can be used to bootstrap Statsig server (takes priority over
- user_persistent_storage: IUserPersistentStorage default nil
- A persistent storage adapter for running sticky experiments.
- network_timeout: Number, default nil
- Maximum number of seconds to wait for a network call before timing out.
Shutting Statsig Down
Because we batch and periodically flush events, some events may not have been sent when your app/server shuts down.
To make sure all logged events are properly flushed, you should tell Statsig to shutdown when your app/server is closing:
Statsig.shutdown
Client SDK Bootstrapping | SSR v0.13.0+
The Ruby server SDK, starting in
0.13.0
supports generating the
initializeValues
needed to bootstrap a Statsig Client SDK
preventing a round trip to Statsig servers. This can also be used with web [
@statsig/js-client
, @statsig/react-bindings
] SDKs to perform server
side rendering (SSR).
values = Statsig.get_client_initialize_response(user); # Hash[String, Any] | Nil
Working with IP or UserAgent Values
This will not automatically use the ip
, or userAgent
for gate evaluation as
Statsig servers would, since there is no request from the client SDK specifying these values.
If you want to use conditions like IP, or conditions which are inferred from the IP/UA like:
Browser Name or Version, OS Name or Version, Country, you must manually set the ip
and userAgent
field on the user object when calling get_client_initialize_response
.
Working with stableID
There is no auto-generated stableID
for device based experimentation,
since the server generates the initialize response without any information from the client SDK.
If you wish to run a device based experiment while using the server to generate the initialize response,
we recommend you:
- Create a customID in the Statsig console. See experimenting on custom IDs for more information.
- Generate an ID on the server, and set it in a cookie to be used on the client side as well.
- Set that ID as the customID on the
StatsigUser
object when generating the initialize response from the SDK. - Get that ID from the cookie, and set it as the customID on the
StatsigUser
object when using the client SDK, so all event data and exposure checks tie back to the same user.
Alternatively, if you wish to use the stableID
field rather than a custom ID, you still need to do step (2) above. Then:
- Override the
stableID
in the client SDK by getting the value from the cookie and setting theoverrideStableID
parameter inStatsigOptions
- Set the
stableID
field on theStatsigUser
object in thecustomIDs
map when generating the initialize response from the SDK
Local Overrides v1.12.0+
If you want to locally override gates/configs/experiments/layers, there are a set of override APIs as follows. Coupling this with StatsigOptions.localMode can be useful when writing unit tests.
# Adding gate overridesStatsig.override_gate("a_gate_name", true)# Adding config overridesStatsig.override_config("a_config_name", {"key" => "value"})
- These only apply locally - they do not update definitions in the Statsig console or elsewhere.
- The local override API is not designed to be a full mock. They are only a convenient way to override the value of the gate/config/etc.
User Persistent Storage
A custom storage adapter that allows the SDK the persist values for users in active experiments. In other words, allowing you to run experiments with sticky bucketing. You can provide a persistent storage adapter via StatsigOptions.UserPersistentStorage.
You can read more about the concept here.
Storage Interface
You can write you own custom storage that implements the following interface:
class IUserPersistentStorage def load(key) nil end def save(key, data) endend
Example Implementation
class DummyPersistentStorageAdapter < Statsig::Interfaces::IUserPersistentStorage attr_accessor :store def initialize @store = {} end def load(key) return nil unless @store&.key?(key) @store[key] end def save(key, data) @store[key] = data endend
Multiple Statsig SDK Instances
Our documentation up to this point guides you through setting up your Statsig integration via the singleton Statsig.
There are cases where you may need to create multiple instances of the Statsig SDK. Each SDK supports this as well - the Statsig singleton wraps a single instance of the SDK that you can instantiate. NOTE: currently all sdk instances will use the same keys when interacting with a Data Store/Data Adapter. You will not be able to isolate multiple instances of the sdk in your data store.
All top level static methods from the singleton carry over as instance methods. To create an instance of the Statsig sdk:
sdk_instance = StatsigDriver.new(secret_key, options, error_callback)
FAQ
How do I run experiments for logged out users?
See the guide on device level experiments
How can I mock or override the SDK for testing?
Starting in v1.12.0+
, the Ruby SDK supports localMode
and overrides
, see Local Overrides
localMode
is a boolean parameter inStatsigOptions
when initializing the SDK. It restricts all network traffic, so the SDK operates offline and only returns default or override values.
Can I generate the initialize response for a client SDK using the Ruby server SDK?
Yes. See Client Initialize Response.
Reference
Type StatsigUser
export type StatsigUser = {class StatsigUser attr_accessor :user_id attr_accessor :email attr_accessor :ip attr_accessor :user_agent attr_accessor :country attr_accessor :locale attr_accessor :app_version attr_accessor :statsig_environment attr_accessor :custom_ids # Hash of key:string value:string attr_accessor :private_attributes # Hash of key:string value:string @custom # Hash of key:string value:string def initialize(user_hash) @statsig_environment = Hash.new if user_hash.is_a?(Hash) @user_id = user_hash['userID'] || user_hash['user_id'] @user_id = @user_id.to_s unless @user_id.nil? @email = user_hash['email'] @ip = user_hash['ip'] @user_agent = user_hash['userAgent'] || user_hash['user_agent'] @country = user_hash['country'] @locale = user_hash['locale'] @app_version = user_hash['appVersion'] || user_hash['app_version'] @custom = user_hash['custom'] if user_hash['custom'].is_a? Hash @statsig_environment = user_hash['statsigEnvironment'] @private_attributes = user_hash['privateAttributes'] if user_hash['privateAttributes'].is_a? Hash custom_ids = user_hash['customIDs'] || user_hash['custom_ids'] @custom_ids = custom_ids if custom_ids.is_a? Hash end endend
Type StatsigOptions
class StatsigOptions attr_accessor :environment attr_accessor :api_url_base attr_accessor :rulesets_sync_interval attr_accessor :idlists_sync_interval attr_accessor :logging_interval_seconds attr_accessor :logging_max_buffer_size attr_accessor :local_mode attr_accessor :bootstrap_values attr_accessor :rules_updated_callback attr_accessor :data_store attr_accessor :idlist_threadpool_size attr_accessor :disable_diagnostics_logging attr_accessor :disable_sorbet_logging_handlers def initialize( environment: T.any(T::Hash[String, String], NilClass), api_url_base: String, rulesets_sync_interval: T.any(Float, Integer), idlists_sync_interval: T.any(Float, Integer), logging_interval_seconds: T.any(Float, Integer), logging_max_buffer_size: Integer, local_mode: T::Boolean, bootstrap_values: T.any(String, NilClass), rules_updated_callback: T.any(Method, Proc, NilClass), data_store: T.any(Statsig::Interfaces::IDataStore, NilClass), idlist_threadpool_size: Integer, disable_diagnostics_logging: T::Boolean, disable_sorbet_logging_handlers: T::Boolean) endend
DataStore
module Statsig module Interfaces class IDataStore def init end def get(key) nil end def set(key, value) end def shutdown end end endend