Default Timeout and Retry Configuration

[rcoh]

Prior to the upcoming BehaviorMajorVersion, if a Rust SDK or smithy client was NOT instantiated using aws_config::load_from_env as baseline configuration, then it would NOT have a default "Connection Timeout" and would default to no retries.

This directly contrasts with the documented behavior. The new behavior version, BehaviorVersion::v2026_01_12(), will enable connection timeouts and retries automatically regardless of how the client was constructed. If you are currently using BehaviorVersionLatest, you will be opted into this automatically.

Recommendations

1. Builders should set appropriate operation_timeouts, operation_attempt_timeouts, and connect_timeouts.
2. For services deployed to production, do NOT use BehaviorVersion::latest to ensure you are aware of all changes in SDK behavior.

Code Examples

When a client is instantiated directly via from_conf and the config builder was NOT instantiated via config::Builder::from(&sdk_config), the retry and timeout settings will not be set:

// WARNING: THIS SETS NO TIMEOUTS.
let client = aws_sdk_dynamodb::Client::from_conf(Config::builder().credentials_provider(...))

If you are using Client::from_conf, to manually set timeouts, use this pattern:

 let config = Config::builder()
        .timeout_config(
            TimeoutConfig::builder()
                .connect_timeout(std::time::Duration::from_secs(4))
                // timeout for the entire operation, including retries
                .operation_timeout(std::time::Duration::from_secs(60))
                // timeout for an individual operation attempt
                .operation_attempt_timeout(std::time::Duration::from_secs(10))
                .build(),
        ).<other settings>.build();
let client = Client::from_conf(config);

// This client will use a connect timeout of 3100ms and use the default AWS retry strategy
let conf = aws_config::load_from_env().await;
let client = aws_sdk_dynamdb::Client::from_conf(config::Builder::from(&conf)).credentials_provider(...)