SDK Patterns — Rust

CAS Optimistic Locking

Read-modify-write without pessimistic locks. Retry on CasMismatch.

use couchbase::error::ErrorKind;
use couchbase::options::kv_options::ReplaceOptions;
use std::future::Future;

async fn update_with_cas(
    collection: &couchbase::collection::Collection,
    key: &str,
) -> Result<(), couchbase::error::Error> {
    loop {
        let get_result = collection.get(key, None).await?;
        let mut doc: serde_json::Value = get_result.content_as()?;
        doc["updated_at"] = serde_json::json!(chrono::Utc::now().timestamp());