attemptify

TypeScript retry library.

Objective

The aim of this module is to simplify the setup and execution of retries. When setting up a retry, there are a number of considerations, such as how long to wait, how many attempts to make, and whether to fail. This module provides a unified procedure for setting up and executing these complicated retries.

Usage

About retry policies

This module provides some retry policies - the policy is the strategy for retry.

• SimpleRetryPolicy ... simply retrying tomax attempts
• ExponentialBackOffRetryPolicy ... wait interval increases exponentialy

Getting started

Try to start from SimpleRetryPolicy to call ofDefaults and boot Attempt with that policy.

const simpleRetry = SimpleRetryPolicy.ofDefaults();

new Attempt(simpleRetry).execute(() => (new Application().run()));

This retry policy has settings that wait for 1 seconds in interval and max attempt count is 5 times. Attempt can execute synchronous or asynchronous, and when asynchronously want to attempt, it is possible to call executeAsync like below:

new Attempt(simpleRetry).executeAsync(() => (new Application().run()));

Attempt enable log for debug, using enableDebugLogging:

new Attempt(simpleRetry)
    .enableDebugLogging()
    .executeAsync(() => (new Application().run()));

Customize retry policy

SimpleRetryPolicy

RetryPolicy can customize its policy setting to set some values to constructors:

const simpleRetry = new SimpleRetryPolicy(seconds(1), 3)

The 1st argument of SimpleRetryPolicy receive Duration instance, passing easily to use msecs / seconds / minutes .

Also, if we want to set a part of settings of policy, a builder is useful. Values that is not set will be defaults.

SimpleRetryPolicy.newBuilder()
      .duration(seconds(1))
      .build();

For all builder settings, see more: Class Builder

ExponentialBackOffRetryPolicy

ExponentialBackOffRetryPolicy also can customize its retry settings by its constructor or builder.

const policy = new ExponentialBackOffRetryPolicy(seconds(1), 4, 2);

The 3rd parameter multiplier will multiply its interval exponentialy. For example, when interval duration is 1 seconds and multiplier is 2, interval is calcurated like 1(sec)^2 .

Like SimpleRetryPolicy, ExponentialBackOffRetryPolicy can be built by builder style.

const policy = ExponentialBackOffRetryPolicy.newBuilder()
      .maxAttempts(2)
      .build();

For all builder settings, see more: Class Builder

docs

All class documents can be seen here: https://simonnozaki.github.io/attemptify/