Rust SDK reference

Overview

This topic documents how to get started with the server-side Rust SDK, and links to reference information on all of the supported features.

Getting started

After you complete the Getting Started process, follow these instructions to start using the LaunchDarkly SDK in your Rust application.

First, install the LaunchDarkly SDK as a dependency in your application.

cargo install cargo-edit
cargo add launchdarkly-server-sdk --allow-prerelease
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Next, import the LaunchDarkly client in your application code:

use launchdarkly_server_sdk::{Client, ConfigBuilder, User};
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After you install and import the SDK, create a single, shared instance of the LaunchDarkly client. Specify your SDK key here so that your application is authorized to connect to LaunchDarkly, your application, and your environment.

Once you have created the client, start the client process and wait for the client to initialize. This SDK depends on the tokio crate to provide a default runtime and as such it is a required dependency.

Only create one instance of client.

Here's how:

#[tokio::main]
async fn main () {
    let config = ConfigBuilder::new(&sdk_key).build();
    let client = Client::build(config).unwrap();
    client.start_with_default_executor();
    if !client.initialized_async().await {
        panic!("Client failed to successfully initialize");
    }
}
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You can use client to check which variation a particular user will receive for a given feature flag.

Here's how:

let user = User::with_key("user@test.com").build();
let show_feature = client.bool_variation(&user, "your.flag.key", false);
if show_feature {
  # application code to show the feature
} else {
  # the code to run if the feature is off
}
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Supported features

This SDK supports the following features:

• Aliasing users
• Configuration
• Evaluating flags
• Flag evaluation reasons
• Flushing events
• Getting all flags
• Identifying and changing users
• Logging configuration
• Offline mode
• Secure mode
• Sending custom events
• Service endpoint configuration
• Shutting down
• User configuration