A DynamoDB abstraction for Rust

Deez is a DynamoDB abstraction for implementing Single Table Design easily, inspired by ElectroDB.

Getting Started

Define a schema for your entities using the Deez procedural macro. Doing so will derive the From conversion traits for your structs and the HashMap<String, AttributeValue> type used by the aws_sdk_dynamodb library, with some additional features for facilitating Single Table Design.

use aws_sdk_dynamodb::types::AttributeValue;
use deez::*;
use std::collections::HashMap;
use uuid::Uuid;

#[derive(Debug, Clone, Deez)]
#[deez_schema(table = "TaskTable", service = "TaskService", entity = "Task")]
#[deez_schema(primary_hash = "pk", primary_range = "sk")]
#[deez_schema(gsi1_name = "gsi1", gsi1_hash = "gsi1pk", gsi1_range = "gsi1sk")]
#[deez_schema(gsi2_name = "gsi2", gsi2_hash = "gsi2pk", gsi2_range = "gsi2sk")]
pub struct Task {
    #[deez_primary(key = "hash")]
    #[deez_gsi1(key = "range", position = 1)]
    #[deez_gsi2(key = "range", position = 1)]
    pub task_id: Option<String>,
    #[deez_primary(key = "range", position = 1)]
    #[deez_gsi1(key = "hash")]
    #[deez_gsi2(key = "range")]
    pub project: Option<String>,
    #[deez_primary(key = "range")]
    #[deez_gsi1(key = "range")]
    #[deez_gsi2(key = "hash")]
    pub employee: Option<String>,
    pub description: String,
    #[deez_ignore(ignore)]
    pub some_metadata: String,
}

impl Default for Task {
    fn default() -> Self {
        Task {
            task_id: Some(Uuid::new_v4().to_string()),
            project: Some("".to_string()),
            employee: Some("".to_string()),
            description: "".to_string(),
            some_metadata: "".to_string(),
        }
    }
}

Now you can convert your struct to a HashMap that you can pass directly to the DynamoDB client.

let task = Task {
    project: Some("foo_project".to_string()),
    employee: Some("e42069".to_string()),
    description: "nothin' but chillin' 20's".to_string(),
    some_metadata: "baz".to_string(),
    ..Default::default()
};

let map: HashMap<String, AttributeValue> = task.into();
println!("{:#?}", map);

// keys are generated based on schema!
// output:
// {
//     "pk": S("$TaskService#Task#task_id_1885ea1d-e296-4c0f-9fbf-863b1318c698"), <-
//     "sk": S("$Task#employee_e42069#project_foo_project"), <-
//     "gsi1pk": S("$TaskService#Task#project_foo_project"), <-
//     "gsi1sk": S("$Task#employee_e42069#task_id_1885ea1d-e296-4c0f-9fbf-863b1318c698"), <-
//     "gsi2pk": S("$TaskService#Task#employee_e42069"), <-
//     "gsi2sk": S("$Task#project_foo_project#task_id_1885ea1d-e296-4c0f-9fbf-863b1318c698"), <-
//     "task_id": S("1885ea1d-e296-4c0f-9fbf-863b1318c698"),
//     "project": S("foo_project"),
//     "employee": S("e42069"),
//     "description": S("nothin' but chillin' 20's"),
// }

The following example shows a practical use-case interacting with DynamoDB client:

use anyhow::Result;
use aws_sdk_dynamodb::Client;

#[tokio::main]
async fn main() -> Result<()> {
    // local configuration
    let client = Client::new(
        &aws_config::from_env()
            .endpoint_url("http://localhost:8000")
            .region("us-east-1")
            .load()
            .await,
    );

    // `create` convenience macro utilizes the `attribute_not_exists()` parameter
    // to ensure records are only “created” and not overwritten when inserting
    // new records into the table.
    create!(
        client;
        Task {
            project: Some("foo_project".to_string()),
            employee: Some("e42069".to_string()),
            description: "nothin' but chillin' 20's".to_string(),
            some_metadata: "baz".to_string(),
            ..Default::default()
        }
    )?;

    let keys = Task {
        task_id: Some("1a2b3c4d".to_string()),
        project: Some("foo_project".to_string()),
        employee: Some("e42069".to_string()),
        ..Default::default()
    }
    .primary_keys();

    // `vec_from_query` macro handles the process of converting the response
    // back to `Vec<Task>`.
    let tasks = vec_from_query!(
        client
            .query()
            .table_name(Task::table_name())
            .key_condition_expression("#pk = :pk and begins_with(#sk, :sk)")
            .set_expression_attribute_names(Some(HashMap::from([
                ("#pk".to_string(), keys.hash.field()),
                ("#sk".to_string(), keys.range.field()),
            ])))
            .set_expression_attribute_values(Some(HashMap::from([
                (":pk".to_string(), keys.hash.av()),
                (":sk".to_string(), keys.range.av()),
            ])))
            .send()
            .await?

        => TaskItems
    );

    // do something with `tasks`...

    Ok(())
}