remote-sync

Remote Sync Example with Turso

This repository contains source code to a example application using libSQL remote sync.

Overview

The scenario in this example is the following:

• A libSQL server runs in a cloud on Turso.
• An application embeds libSQL database, which periodically syncs with the server.

Getting Started

First, create a database on Turso:

turso db create sync-example

Then create the schema and insert some data for this example application:

turso db shell sync-example

CREATE TABLE users (
    user_id INT PRIMARY KEY,
    name TEXT
);

CREATE TABLE keycards (
    keycard_id INT PRIMARY KEY,
    user_id INT,
    expired BOOL,
    FOREIGN KEY (user_iD) REFERENCES users(user_id)
);

INSERT INTO users VALUES (1, 'Glauber');
INSERT INTO keycards VALUES (1, 1, false);

First step: Running remotely

To run remotely, configure the DB_URL and AUTH_TOKEN environment variables, while making sure that SYNC_URL is not set:

unset SYNC_URL
export DB_URL=$(turso db show --url sync-example)
export AUTH_TOKEN=$(turso db tokens create sync-example)

and run the example application:

bun query.ts

and you should see the following output, repeated 10 times:

The keycard for user Glauber is valid.

Second step: Running an embedded replica

Configure the SYNC_URL and AUTH_TOKEN environment variables, and set DB_URL to a local file:

export DB_URL="file:local.db"
export SYNC_URL=$(turso db show --url sync-example)
export AUTH_TOKEN=$(turso db tokens create sync-example)

and then run the example application:

bun query.ts

and you should see the following output, repeated 10 times:

The keycard for user Glauber is valid.

Updates

You can now update data on the remote database. Two scripts are provided for that:

To set the card as valid:

bun validate.ts

To set the card as expired:

bun expire.ts

run bun query.ts to inspect for changes, and adjust your environment variables to switch between remote execution and embedded replicas, and notice the difference between them!