@adobe/node-fetch-retry
Library for performing retries on HTTP requests
Last updated a month ago by adobe-admin .
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node-fetch-retry

Node Module for performing retries for HTTP requests.

It is a wrapper around node-fetch library. It has default retry logic built in as described below, as well as configurable parameters. It also has built-in support for Apache OpenWhisk actions, adjusting the timeout to reflect the action timeout.

Installation

npm install @adobe/node-fetch-retry

Usage

This library works the same as the normal fetch api, but with some added features.

Default Behavior

Without configuring any parameters, the retry behavior will be as follows:

  • retry for 60s
  • retry inital delay of 100ms with exponential backoff
  • retry only on 5xx response
  • socket timeout of 30s
const fetch = require('@adobe/node-fetch-retry');

async main() {
    const response = await fetch(url);
}

This example uses only custom headers and will use default retry settings:

const fetch = require('@adobe/node-fetch-retry');

async main() {
    const response = await fetch(url, {
        headers: {
            'custom-header': '<<put custom header value here>>'
        }
    });
}

Optional Custom Parameters

All the retry options are configurable and can be set in retryOptions in the options object passed to fetch.

Parameter Format Description Environment variable Default Value
retryMaxDuration Number time in milliseconds to retry until throwing an error NODE_FETCH_RETRY_MAX_RETRY 60000 ms
retryInitialDelay Number time in milliseconds to wait between retries NODE_FETCH_RETRY_INITIAL_WAIT 100 ms
retryBackoff Number backoff factor for wait time between retries NODE_FETCH_RETRY_BACKOFF 2.0
retryOnHttpResponse Function a function determining whether to retry given the HTTP response none retry on all 5xx errors
socketTimeout Number time until socket timeout in milliseconds. Note: if socketTimeout is >= retryMaxDuration, it will automatically adjust the socket timeout to be exactly half of the retryMaxDuration. To disable this feature, see forceSocketTimeout below NODE_FETCH_RETRY_SOCKET_TIMEOUT 30000 ms
forceSocketTimeout Boolean If true, socket timeout will be forced to use socketTimeout property declared regardless of the retryMaxDuration. Note: this feature was designed to help with unit testing and is not intended to be used in practice NODE_FETCH_RETRY_FORCE_TIMEOUT false

Note: the environment variables override the default values if the corresponding parameter is not set. These are designed to help with unit testing. Passed in parameters will still override the environment variables

Custom Parameter Examples

This example decreases the retryMaxDuration and makes the retry delay a static 500ms. This will do no more than 4 retries.

const fetch = require('@adobe/node-fetch-retry');

async main() {
    const response = await fetch(url, {
        retryOptions: {
            retryMaxDuration: 2000,  // 30s retry max duration
            retryInitialDelay: 500,
            retryBackoff: 1.0 // no backoff
        }
    });
}

This example shows how to configure retries on specific HTTP responses:

const fetch = require('@adobe/node-fetch-retry');

async main() {
    const response = await fetch(url, {
        retryOptions: {
            retryOnHttpResponse: function (response) {
                if ( (response.status >= 500) || response.status >= 400) { // retry on all 5xx and all 4xx errors
                    return true;
                }
            }
        }
    });
}

This example uses custom socketTimeout values:

const fetch = require('@adobe/node-fetch-retry');

async main() {
    const response = await fetch(url, {
        retryOptions: {
            retryMaxDuration: 300000, // 5min retry duration
            socketTimeout: 60000, //  60s socket timeout
        }
    });
}

This example uses custom socketTimeout values and custom headers:

const fetch = require('@adobe/node-fetch-retry');

async main() {
    const response = await fetch(url, {
        retryOptions: {
            retryMaxDuration: 300000, // 5min retry duration
            socketTimeout: 60000, //  60s socket timeout
        },
        headers: {
            'custom-header': '<<put custom header value here>>'
        }
    });
}

Disable Retry

You can disable all retry behavior by setting retryOptions to false.

const fetch = require('@adobe/node-fetch-retry');

async main() {
    const response = await fetch(url, {
        retryOptions: false
    });
}

Disabling retry behavior will not prevent the usage of other options set on the options object.

Apache OpenWhisk Action Support

If you are running this in the context of an OpenWhisk action, it will take into account the action timeout deadline when setting the retryMaxDuration. It uses the __OW_ACTION_DEADLINE environment variable to determine if there is an action running.

Behavior: If retryMaxDuration is greater than the time till the action will timeout, it will adjust the retryMaxDuration to be equal to the time till action timeout.

Contributing

Contributions are welcomed! Read the Contributing Guide for more information.

Licensing

This project is licensed under the Apache V2 License. See LICENSE for more information.

Current Tags

  • 1.1.0                                ...           latest (a month ago)

3 Versions

  • 1.1.0                                ...           a month ago
  • 1.0.1                                ...           7 months ago
  • 1.0.0                                ...           7 months ago

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