Dynarust

An opinionated DynamoDB ODM library for Rust that maps structs to native Dynamo items using serde and serde_json.

It only works with tables with a HASH key and a RANGE key, referred in the code as pk and sk. This setup can be useful for a very wide variety of use cases.

use serde::{Deserialize, Serialize};
use serde_json::json;

#[derive(Serialize, Deserialize)]
struct Car {
    brand: String,
    model: String,
    horse_power: i64
}

impl dynarust::Resource for Car {
    fn table() -> String { "Cars".into() }
    fn pk_sk(&self) -> (String, String) { (self.brand.clone(), self.model.clone()) }
}

#[tokio::main]
async fn main() -> Result<()> {
    let client = dynarust::Client::aws().await;
    
    let car = Car {
        brand: "Tesla",
        model: "Y",
        horse_power: 347
    };
    
    client.create(&car).await?;
    
    client.update(&car, json!({ "horse_power": 534 })).await?;
    
    let tesla = client.get::<Car>(("Tesla".into(), "Y".into())).await?;
    
    assert_eq!(tesla.unwrap().horse_power, 534)
}

Setup

In order to use this library, the table setup would need to look like this equivalent CFN template:

DynamoDBTable:
  Type: AWS::DynamoDB::Table
  Properties:
    TableName: my-table
    AttributeDefinitions:
      - AttributeName: PrimaryKey
        AttributeType: S
      - AttributeName: SecondaryKey
        AttributeType: S
    KeySchema:
      - AttributeName: PrimaryKey
        KeyType: HASH
      - AttributeName: SecondaryKey
        KeyType: RANGE

dynarust expects that attributes PrimaryKey and SecondaryKey are declared in the key schema as HASH and RANGE values, and that both are of type S (string).

Coming next

• Support for global secondary indexes, with the same API that exists right now for the primary ones.

Current Limitations

• Only works with the HASH and RANGE keys setup.
• It is not compatible with global or local secondary indexes.
• Missing some batch operations, right now only batch_get is implemented.