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https://github.com/vizir/idempotent-aws-lambda
A fast way to turn your aws lambda idempotent
https://github.com/vizir/idempotent-aws-lambda
Last synced: 16 days ago
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A fast way to turn your aws lambda idempotent
- Host: GitHub
- URL: https://github.com/vizir/idempotent-aws-lambda
- Owner: Vizir
- License: mit
- Created: 2020-05-23T19:49:00.000Z (over 4 years ago)
- Default Branch: master
- Last Pushed: 2023-01-06T06:47:38.000Z (about 2 years ago)
- Last Synced: 2024-04-26T18:46:09.456Z (9 months ago)
- Language: TypeScript
- Size: 1.74 MB
- Stars: 2
- Watchers: 9
- Forks: 1
- Open Issues: 17
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# @vizir/idempotent-aws-lambda
A fast way to turn your aws lambda function idempotent.
[](https://badge.fury.io/js/%40vizir%2Fidempotent-aws-lambda)
## Motivation
This library is design to resolve the idempotent problem of the AWS Lambda.
Some kind of request into AWS lambda should run most than one time, generating inconsistency problems when your
function isn't idempotent. You can check more details into [aws knowledge center](https://aws.amazon.com/premiumsupport/knowledge-center/lambda-function-idempotent)
## Installation
```sh
$ npm install @vizir/idempotent-aws-lambda
```
## Usage
### HTTP
Use the default aws request id to avoid duplicate requests:
```javascript
module.exports.handler = idempotencyHttpWrapper({
handler: async (event, context) => {
// Your lambda functions goes here
console.log("Processing message", event, context);
// The return will be cached into provider
return "OK";
},
provider: {
endpoint: "http://localhost:8000", // used for local development only
name: "dynamoDB",
region: "us-east-1",
tableName: "my-idempotent-table",
},
ttl: 5, // ttl in seconds
id: {
from: "requestId",
},
});
```
Use the request header to extract the idempotency id.
```javascript
module.exports.handler = idempotencyHttpWrapper({
handler: async (event, context) => {
// Your lambda functions goes here
console.log("Processing message", event, context);
// The return will be cached into provider
return "OK";
},
provider: {
endpoint: "http://localhost:8000", // used for local development only
name: "dynamoDB",
region: "us-east-1",
tableName: "my-idempotent-table",
},
ttl: 5, // ttl in seconds
id: {
from: "header",
name: "myIdempotencyHeader",
},
});
```
Use the request header to extract the idempotency id (with aws request id when header is empty):
```javascript
module.exports.handler = idempotencyHttpWrapper({
handler: async (event, context) => {
// Your lambda functions goes here
console.log("Processing message", event, context);
// The return will be cached into provider
return "OK";
},
provider: {
endpoint: "http://localhost:8000", // used for local development only
name: "dynamoDB",
region: "us-east-1",
tableName: "my-idempotent-table",
},
ttl: 5, // ttl in seconds
id: {
from: "header",
name: "myIdempotencyHeader",
fallback: true,
},
});
```
### SQS
Prevent duplicate calls into sqs trigger. The ttl cannot be high to avoid retry problems.
The own aws can call your lambda twice, in this case we will ignore and remove from SQS.
There are two ways to handle the idempotency SQS.
One is as follow the example bellow, which means the idempotency key will be the messageId from SQS.
```javascript
module.exports.sqsHandler = idempotencySQSWrapper({
handler: async (event, context) => {
console.log("Processing message", event, context);
return "OK";
},
provider: {
endpoint: process.env.ENDPOINT,
name: "dynamoDB",
region: process.env.REGION,
tableName: process.env.TABLE_NAME,
},
queue: {
region: process.env.REGION,
url: process.env.QUEUE_URL,
},
ttl: 5,
});
```
Another way is customizing the idempotency's key, from the payload of the received message.
Let's suppose the message's body is
```
stream: { eventType: 'SENT', id: '1234567890' }
```
The idempotency's configuration will be:
```javascript
module.exports.sqsHandler = idempotencySQSWrapper({
handler: async (event, context) => {
console.log("Processing message", event, context);
return "OK";
},
provider: {
endpoint: process.env.ENDPOINT,
name: "dynamoDB",
region: process.env.REGION,
tableName: process.env.TABLE_NAME,
},
queue: {
region: process.env.REGION,
url: process.env.QUEUE_URL,
},
ttl: 5,
id: {
from: "event",
name: ["stream.id", "stream.eventType"],
},
});
```
The result in the table will be a recod, which the key will be: `1234567890SENT`.
## Support
Tested in Node.js 10-12.
## License
[The MIT License (MIT)](./LICENSE)