In today’s world, where data is generated rapidly and from various sources, it is crucial to have an efficient and seamless way to synchronize data between different systems. In this blog post, we will explore how to implement data synchronization between IndexedDB and Apache Livy using JavaScript.

What is IndexedDB?

IndexedDB is a web standard database API that allows for storing and retrieving large amounts of structured data on the client-side. It is supported by most modern web browsers and provides a way to create offline applications or cache data for faster retrieval.

What is Apache Livy?

Apache Livy is an open-source REST interface for interacting with Apache Spark from anywhere. It enables remote Spark job submission, query execution, and data retrieval. With Livy, you can run Spark jobs using a wide range of programming languages such as Java, Scala, and Python.

Implementing Data Synchronization

To synchronize data between IndexedDB and Apache Livy, we can follow these steps:

1. Store Data Locally: In IndexedDB, store the data that needs to be synchronized. You can use the IndexedDB API to create a database, define an object store, and add or retrieve data from it.

// Connect to IndexedDB
const dbPromise = indexedDB.open('myDatabase', 1);

dbPromise.onupgradeneeded = function(event) {
  const db = event.target.result;
  const store = db.createObjectStore('myStore', { keyPath: 'id' });
};

dbPromise.onsuccess = function(event) {
  const db = event.target.result;

  // Store data in IndexedDB
  const transaction = db.transaction('myStore', 'readwrite');
  const store = transaction.objectStore('myStore');
  
  store.add({ id: 1, name: 'John Doe' });
};

dbPromise.onerror = function(event) {
  console.error('Error connecting to IndexedDB', event.target.error);
};

1. Send Data to Apache Livy: Use the Livy REST API to send the data from IndexedDB to Apache Livy. You can make a POST request to the /batches endpoint with the data payload.

// Send data to Apache Livy
fetch('http://localhost:8998/batches', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({ id: 1, name: 'John Doe' }),
})
  .then(response => response.json())
  .then(data => console.log('Data sent to Livy', data))
  .catch(error => console.error('Error sending data to Livy', error));

1. Retrieve Data from Apache Livy: Use the Livy REST API to retrieve the synchronized data from Apache Livy. You can make a GET request to the /batches/{batchId}/log endpoint to get the log output of the Spark job execution.

// Retrieve data from Apache Livy
fetch('http://localhost:8998/batches/{batchId}/log')
  .then(response => response.json())
  .then(data => console.log('Data retrieved from Livy', data))
  .catch(error => console.error('Error retrieving data from Livy', error));

1. Update IndexedDB: Once the synchronized data is retrieved from Apache Livy, update the IndexedDB with the new or modified data.

// Update data in IndexedDB
dbPromise.onsuccess = function(event) {
  const db = event.target.result;

  // Update data in IndexedDB
  const transaction = db.transaction('myStore', 'readwrite');
  const store = transaction.objectStore('myStore');

  store.put({ id: 1, name: 'Jane Doe' });
};

By following these steps, you can achieve data synchronization between IndexedDB and Apache Livy seamlessly. This can be useful in scenarios where data needs to be stored locally and synchronized with a server-side Spark processing system.

#dataSynchronization #IndexedDB #ApacheLivy