How to do automatic retries with `supabase-js`

You should only enable retries if your requests fail with network errors (e.g. 520 status from Cloudflare). A high number of retries have the potential to exhaust the Data API connection pool, which could result in lower throughput and failed requests.

The fetch-retry package allows you to add retry logic to fetch requests, making it a useful tool for enhancing the resilience of API calls in your Supabase applications. Here's a step-by-step guide on how to integrate fetch-retry with the supabase-js library.

1. Install dependencies

To get started, ensure you have both supabase-js and fetch-retry installed in your project:

npm install @supabase/supabase-js fetch-retry

2. Wrap the fetch function

The fetch-retry package works by wrapping the native fetch function. You can create a custom fetch instance with retry logic and pass it to the supabase-js client.

import { createClient } from '@supabase/supabase-js'
import fetchRetry from 'fetch-retry'

// Wrap the global fetch with fetch-retry
const fetchWithRetry = fetchRetry(fetch)

// Create a Supabase client instance with the custom fetch
const supabase = createClient(
  'https://your-supabase-url.supabase.co',
  'sb_publishable_... or anon key',
  {
    global: {
      fetch: fetchWithRetry,
    },
  }
)

3. Configure retry options

You can configure fetch-retry options to control retry behavior, such as the number of retries, retry delay, and which errors should trigger a retry.

Here is an example with custom retry options:

const fetchWithRetry = fetchRetry(fetch, {
  retries: 3, // Number of retry attempts
  retryDelay: (attempt) => Math.min(1000 * 2 ** attempt, 30000), // Exponential backoff
  retryOn: [520], // Retry only on Cloudflare errors
})

In this example, the retryDelay function implements an exponential backoff strategy, and retries are triggered only for specific HTTP status codes.

4. Using the Supabase client

With fetch-retry integrated, you can use the Supabase client as usual. The retry logic will automatically apply to all network requests made by supabase-js.

async function fetchData() {
  const { data, error } = await supabase.from('your_table').select('*')

  if (error) {
    console.error('Error fetching data:', error)
  } else {
    console.log('Fetched data:', data)
  }
}

fetchData()

5. Fine-Tuning retries for specific requests

If you need different retry logic for certain requests, you can use the retryOn with a custom function to inspect the URL or response and decide whether to retry the request.

const fetchWithRetry = fetchRetry(fetch, {
  retryDelay: (attempt) => Math.min(1000 * 2 ** attempt, 30000),
  retryOn: (attempt, error, response) => {
    const shouldRetry
      = (attempt: number, error: Error | null, response: Response | null) =>
        attempt < 3
          && response
          && response.status == 520 // Cloudflare errors
          && response.url.includes('rpc/your_stored_procedure')

    if (shouldRetry(attempt, error, response)) {
      console.log(`Retrying request... Attempt #${attempt}`, response)
      return true
    }

    return false
  }
})

async function yourStoredProcedure() {
  const { data, error } = await supabase
    .rpc('your_stored_procedure', { param1: 'value1' });

  if (error) {
    console.log('Error executing RPC:', error);
  } else {
    console.log('Response:', data);
  }
}

yourStoredProcedure();

By using retryOn with a custom function, you can define specific conditions for retrying requests. In this example, the retry logic is applied only to requests targeting a specific stored procedure.

Conclusion

Integrating fetch-retry with supabase-js is a straightforward way to add robustness to your Supabase API requests. By handling transient errors and implementing retry strategies, you can improve the reliability of your application while maintaining a seamless user experience.