# Connect SlateDB to S3

> Learn how to connect SlateDB to Amazon S3 using LocalStack

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

## Create a project

Let's start by creating a new Rust project:

```bash
cargo init slatedb-playground
cd slatedb-playground
```

## Add dependencies

Now add SlateDB and the required dependencies to your `Cargo.toml`:

```bash
cargo add slatedb tokio --features tokio/macros,tokio/rt-multi-thread
cargo add object-store --features object-store/aws
cargo add anyhow
```

:::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. SlateDB also exports `slatedb::object_store` for convenience, if you'd rather use that.

:::

## Setup

You will need to have [LocalStack](https://localstack.cloud/) running. You can install it using [Homebrew](https://brew.sh/):

```bash
brew install localstack/tap/localstack-cli
```

```bash
localstack start -d
```

For a more detailed setup, see the [LocalStack documentation](https://docs.localstack.cloud/).

You'll also need the AWS CLI:

```bash
brew install awscli
```

## Initialize AWS

SlateDB requires a bucket to work with S3.

### Create your S3 bucket:

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

## Write some code

Stick this into your `src/main.rs` file:
<!-- could not inline /home/runner/work/slatedb/examples/src/s3_compatible.rs -->

:::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:

```bash
cargo run
```

This will write a 64 MiB value to SlateDB.

## Check the results

Now' let's check the database path in the bucket:

```bash
% aws --endpoint-url=http://localhost:4566 s3 ls s3://slatedb/tmp/slatedb_s3_compatible/
                           PRE compacted/
                           PRE compactions/
                           PRE manifest/
                           PRE wal/
```

There are four folders:

- `manifest`: Contains the manifest files. Manifest files define the state of the DB, including the set of SSTs that are part of the DB.
- `wal`: Contains the write-ahead log files.
- `compacted`: Contains the compacted SST files (may not appear in short examples).
- `compactions`: Contains the compaction-state snapshots.

Let's check the `wal` folder:

```bash
% aws --endpoint-url=http://localhost:4566 s3 ls s3://slatedb/tmp/slatedb_s3_compatible/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 (WAL) file, and each WAL file can contain many `RowEntry` values. They get flushed based on the `flush_interval` config. The last WAL file is 64 MiB because it contains the value we wrote.

Finally, let's check the `compacted` folder:

```bash
% aws --endpoint-url=http://localhost:4566 s3 ls s3://slatedb/tmp/slatedb_s3_compatible/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.