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Python Server SDK for Statsig

Statsig server SDK for Python applications. This SDK is open source and hosted on github.

The Basics#

Get started in a few quick steps.

  1. Create a free account on statsig.com
  2. Install the SDK
  3. Initialize the SDK
  4. Fetch Feature Gates, Dynamic Configs, or Experiments
  5. Log a custom event

Step 1 - Create a free account on www.statsig.com#

You could skip this for now, but you will need an SDK Key and some Feature Gates or Dynamic Configs to use with the SDK in just a minute.

Step 2 - Install the SDK#

Install the sdk using pip:

pip install statsig
info

The python SDK is currently a lightweight wrapper around a shared library built from our Go sdk. If you do not have Go installed, pip will fail to install Statsig. We are working on building out a fully native python SDK, so bear with us until that is complete.

Step 3 - Initialize the SDK#

After installation, you will need to initialize the SDK using a Server Secret Key from the statsig console.

info

Do NOT embed your Server Secret Key in client side applications, or expose it in any external facing documents. However, if you accidentally exposed it, you can create a new one in Statsig console.

There is also an optional parameter options that allows you to pass in a StatsigOptions to customize the SDK.

from statsig import statsig
statsig.initialize('server-secret-key')

initialize will perform a network request. After initialize completes, virtually all SDK operations will be synchronous1--the SDK will fetch updates from Statsig in the background, independently of your API calls.

Step 4 - Fetch Feature Gates, Dynamic Configs, or Experiments#

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 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:

statsig.check_gate(StatsigUser("user-id"), "gate-name")

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(StatsigUser("user-id"), "config-name")
config_json = config.get_value()

Then we have Experiments, which you can use to run A/B/n experiments and use advanced features like layers (coming soon) to avoid collision and enable quicker iterations with parameter reuse.

experiment = statsig.get_experiment(StatsigUser("user-id"), "experiment-name")
experiment_json = experiment.get_value()

Step 5 - Log a custom 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:

from statsig.statsig_user import StatsigUser
from statsig.statsig_event import StatsigEvent
statsig.log_event(StatsigEvent(StatsigUser("user-id"), "event-name"))

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.

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#

statsig.initialize() takes an optional parameter options in addition to the secret key that you can provide to customize the Statsig client. Here are the current options and we are always adding more to the list:

  • environment: StatsigEnvironment, default None

    • An object 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 environment tier ('production', 'staging' or 'development'), e.g. { tier: 'staging' }, and have feature gates pass/fail for specific environments.

Shutting down Statsig#

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()

FAQ#

How do I run experiments for logged out users?#

(Coming soon)

Where's all the code?#

The python sdk is implemented as a lightweight wrapper around a shared library (statsig/shared/statsig.so). This library is compiled from the statsig go sdk. We will evaluate building a pure python SDK based on how this performs along with usage of the SDK itself. Happy coding!