@creejs/commons-retrier

Commons-retrier Library provides a Retrier to:

• Retry a task until it matches what you want

• Options:

  • Times

    The max retires, how many times can we try?

  • Intervals

    After a retrying, what delay should we wait for?

    • Minimum Interval
    • Maximum Interval
    • Change Policy
      • Fixed Interval Policy
      • Fixed Increase Policy
      • Factor Increase Policy
      • Shuttle Policy
      • Exponential Backoff with Jitter
      • Fixed Backoff with Jitter
      • Linear Backoff with Jitter

  • Timeout

    After the "timeout", whole retries will fail with last error

  • TaskTimeout

    Timeout of one Task execution

And it supports two types of usage:

1. retry(task)

   Run the task at intervals, until the task succeeds.

2. always(task)

   Always run the task again and again, despit it fails or succeeds, until reaching the maxRetries, or total timeout

Install

npm intall @creejs/commons-retrier

Usage

1. retry(task)

      const { Retrier } = require('@creejs/commons-retrier')
      
   // Chainable API to create and initialize Retrier
   const retrier = Retrier.infinite() // no retry limit
     .min(100) // min interval, 100ms
     .max(300) // max interval, 300ms
     .fixedIncrease(20) // each call, increase interval by 20ms
      
   // Task function to be retried
   const task = (retries, latency) => {
     if (retries <= 3) { // failed 3 times
       throw new Error('Task failed') // fails, if throw error, or reject promise
     }
     return 'success' // succeed at 4th try
   }
   // will end retries when first successfully call happens
   (async () => {
     try {
       const rtnVal = await retrier.task(task).start()
       console.log(rtnVal)
       // --> success
     } catch (err) {
       console.log(err)
     }
   })()

2. always(task)

         
   const { Retrier } = require('@creejs/commons-retrier')
      
   // Chainable API to create and initialize Retrier
   const retrier = Retrier.times(4) // max retry 4 times
     .min(100) // min interval, 100ms
     .max(300) // max interval, 300ms
     .fixedIncrease(20) // each call, increase interval by 20ms
     .onSuccess((taskResult, retries, latency) => {
       console.log(taskResult)
     })
     .onFailure((err, retries, latency) => {
       console.error(err.message)
     })
     .onMaxRetries((nextRetries, maxRetries) => {
       console.error(`Max retries reached, ${nextRetries} > maxRetries ${maxRetries}`)
     })
      
   // Task function to be retried
   const task = (retries, latency) => {
     // succeed at 1, 2 try
     if (retries <= 2) {
       return `Latency ${latency}ms, Task succeeded at ${retries} try`
     }
     // fails at 3, 4 try, if throw error, or reject promise
     throw new Error(`Latency ${latency}ms, Task failed at ${retries} try`)
   }
      
   // will end retries when reach max retries
   (async () => {
     try {
       await retrier.always(task).start()
      
       console.log('Finished All Retries')
       // --> Latency 0ms, Task succeeded at 1 try
       // --> 105ms, Task succeeded at 2 try
       // --> Latency 228ms, Task failed at 3 try
       // --> Latency 370ms, Task failed at 4 try
       // --> Max retries reached, 5 > maxRetries 4
       // --> Finished All Retries
     } catch (err) {
       console.log(err)
     }
   })()