Connect SlateDB to S3

This tutorial shows you how to connect SlateDB to S3. We'll use LocalStack to simulate S3 and DynamoDB.

Create a project

Let's start by creating a new Rust project:

cargo init slatedb-playground
cd slatedb-playground

Add dependencies

Now add SlateDB and the object_store crate to your Cargo.toml:

cargo add slatedb object-store --features object-store/aws

note

If you see "object_store::path::Path and object_store::path::Path have similar names, but are actually distinct types", you might need to pin the object_store version to match slatedb's object_store version.

Setup

You will need to have LocalStack running. You can install it using Homebrew:

brew install localstack/tap/localstack-cli

localstack start -d

For a more detailed setup, see the LocalStack documentation.

You'll also need the AWS CLI:

brew install awscli

Initialize AWS

SlateDB requires a bucket and a DynamoDB table to work with S3.

Create your S3 bucket:

# Create S3 bucket
aws --endpoint-url=http://localhost:4566 s3api create-bucket --bucket slatedb --region us-east-1

Create your DynamoDB table:

SlateDB has not yet implemented CAS for S3 (#164). Instead, SlateDB uses DynamoDB to manage CAS (via the object_store crate).

# Create DynamoDB table
aws --endpoint-url=http://localhost:4566 dynamodb create-table --table-name slatedb --key-schema AttributeName=path,KeyType=HASH AttributeName=etag,KeyType=RANGE --attribute-definitions AttributeName=path,AttributeType=S AttributeName=etag,AttributeType=S --billing-mode PAY_PER_REQUEST
aws --endpoint-url=http://localhost:4566 dynamodb update-time-to-live --table-name slatedb --time-to-live-specification Enabled=true,AttributeName=ttl

Write some code

Stick this into your src/main.rs file:

use object_store::aws::{DynamoCommit, S3ConditionalPut};
use object_store::path::Path;
use object_store::ObjectStore;
use slatedb::config::DbOptions;
use slatedb::db::Db;
use std::sync::Arc;

#[tokio::main]
async fn main() {
    let db_options = DbOptions::default();
    let path = Path::from("test");
    let os: Arc<dyn ObjectStore> = Arc::new(
        object_store::aws::AmazonS3Builder::new()
            // These will be different if you are using real AWS
            .with_allow_http(true)
            .with_endpoint("http://localhost:4566")
            .with_access_key_id("test")
            .with_secret_access_key("test")
            .with_bucket_name("slatedb")
            .with_region("us-east-1")
            .with_conditional_put(S3ConditionalPut::Dynamo(DynamoCommit::new("slatedb".to_string())))
            .build()
            .expect("failed to create object store")
    );
    let db = Db::open_with_opts(path.clone(), db_options, os.clone())
        .await
        .expect("failed to open db")

    // Call db.put with a key and a 64 meg value to trigger L0 SST flush
    let value: Vec<u8> = vec![0; 64 * 1024 * 1024];
    db.put(b"k1", value.as_slice()).await;
    db.close().await.expect("failed to close db");
}

note

Our code example writes a 64 MiB value to object storage to trigger an L0 SST flush. This is just to show the compacted directory in your bucket.

Run the code

Now you can run the code:

cargo run

This will write a 64 MiB value to SlateDB.

Check the results

Now' let's check the root of the bucket:

aws --endpoint-url=http://localhost:4566 s3 ls s3://slatedb/test/    
                           PRE compacted/
                           PRE manifest/
                           PRE wal/

There are three folders:

• compacted: Contains the compacted SST files.
• manifest: Contains the manifest files.
• wal: Contains the write-ahead log files.

Let's check the wal folder:

aws --endpoint-url=http://localhost:4566 s3 ls s3://slatedb/test/wal/
2024-09-04 18:05:57         64 00000000000000000001.sst
2024-09-04 18:05:58   67108996 00000000000000000002.sst

Each of these SST files is a write-ahead log entry. They get flushed based on the flush_interval config. The last entry is 64 MiB, which is the value we wrote.

Finally, let's check the compacted folder:

% aws --endpoint-url=http://localhost:4566 s3 ls s3://slatedb/test/compacted/ 
2024-09-04 18:05:59   67108996 01J6ZVEZ394GCJT1PHZYY1NZGP.sst

Again, we see the 64 MiB SST file. This is the L0 SST file that was flushed with our value. Over time, the WAL entries will be removed, and the L0 SSTs will be compacted into higher levels.