https://github.com/starhoshi/mission-completed

Stop processing even if Cloud Functions fires multiple times.
https://github.com/starhoshi/mission-completed

cloudfunctions firebase firestore javascript npm typescript

Last synced: about 3 hours ago
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Stop processing even if Cloud Functions fires multiple times.

• Host: GitHub
• URL: https://github.com/starhoshi/mission-completed
• Owner: starhoshi
• License: mit
• Created: 2018-02-11T06:33:00.000Z (almost 7 years ago)
• Default Branch: master
• Last Pushed: 2018-04-04T07:37:32.000Z (over 6 years ago)
• Last Synced: 2024-11-07T10:41:21.851Z (12 days ago)
• Topics: cloudfunctions, firebase, firestore, javascript, npm, typescript
• Language: TypeScript
• Homepage:
• Size: 354 KB
• Stars: 6
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        


    



# mission-completed

[![npm version](https://badge.fury.io/js/mission-completed.svg)](https://badge.fury.io/js/mission-completed)

[![Build Status](https://travis-ci.org/starhoshi/mission-completed.svg?branch=master)](https://travis-ci.org/starhoshi/mission-completed)

[![Codacy Badge](https://api.codacy.com/project/badge/Grade/bb251ccd81c148cda6cf7322da394e3a)](https://www.codacy.com/app/kensuke1751/mission-completed?utm_source=github.com&utm_medium=referral&utm_content=starhoshi/mission-completed&utm_campaign=Badge_Grade)

[![License: MIT](https://img.shields.io/badge/License-MIT-green.svg)](https://opensource.org/licenses/MIT)

> Note: Trigger events are delivered at least once, which means that rarely, spurious duplicates may occur.

> https://cloud.google.com/functions/docs/concepts/events-triggers#triggers

Cloud Functions rarely fire multiple times.

If __multiple payment occurs__, it is a big problem!!

mission-completed uses __transactions__ to prevent multiple trigger events.

If you try to set the completed flag to true many times, CompletedError will be returned.

```ts

await Mission.markCompleted(ref, id) // first: success

await Mission.markCompleted(ref, id) // second: throw CompletedError

```

Results are saved like this.



## Install

```

yarn install mission-completed

```

## Usage

This sample is written in TypeScript.

### 1. Initialize

Initialize event-response in your index.ts.

```ts

import * as Mission from 'mission-completed'

import * as functions from 'firebase-functions'

Mission.initialize(functions.config().firebase)

```

### 2. mark completed in Cloud Functions

If mission has already been completed, throw CompletedError in `Mission.markCompleted(event.data.ref, 'updateUser')`.

```ts

exports.updateUser = functions.firestore.document('users/{userId}')

  .onCreate(async event => {

    try {

      await Mission.markCompleted(event.data.ref, 'updateUser')

    } catch (error) {

      if (error.constructor === Mission.CompletedError) {

        console.error(error, 'Mission has already been completed.')

        return Promise.reject(error)

      }

    }

    await event.data.ref.update({updated: true})

    return undefined

})

```

This will continue the initial process, but the simultaneous firing process will stop with CompletedError.

## License

MIT