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    2.0.1 • Public • Published

    Middy intput-out-logger middleware

    Middy logo

    STS middleware for the middy framework, the stylish Node.js middleware engine for AWS Lambda

    Fetches STS credentials to be used when connecting to other AWS services.


    To install this middleware you can use NPM:

    npm install --save @middy/sts


    • AwsClient (object) (default AWS.STS): AWS.STS class constructor (e.g. that has been instrumented with AWS XRay). Must be from aws-sdk v2.
    • awsClientOptions (object) (optional): Options to pass to AWS.STS class constructor.
    • awsClientCapture (function) (optional): Enable XRay by passing captureAWSClient from aws-xray-sdk in.
    • fetchData (object) (required): Mapping of internal key name to API request parameters.
    • disablePrefetch (boolean) (default false): On cold start requests will trigger early if they can. Setting awsClientAssumeRole disables prefetch.
    • cacheKey (string) (default sts): Internal cache key for the fetched data responses.
    • cacheExpiry (number) (default -1): How long fetch data responses should be cached for. -1: cache forever, 0: never cache, n: cache for n ms.
    • setToContext (boolean) (default false): Store credentials to request.context.


    • Lambda is required to have IAM permission for sts:AssumeRole
    • setToContext are included for legacy support and should be avoided for performance and security reasons. See main documentation for best practices.

    Sample usage

    import middy from '@middy/core'
    import sts from '@middy/sts'
    const handler = middy((event, context) => {
      const response = {
        statusCode: 200,
        headers: {},
        body: JSON.stringify({ message: 'hello world' })
      return response
        fetchData: {
          assumeRole: {
            RoleArn: '...',
            RoleSessionName:'' // optional

    Middy documentation and examples

    For more documentation and examples, refers to the main Middy monorepo on GitHub or Middy official website.


    Everyone is very welcome to contribute to this repository. Feel free to raise issues or to submit Pull Requests.


    Licensed under MIT License. Copyright (c) 2017-2021 Luciano Mammino, will Farrell, and the Middy team.

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    npm i @middy/sts

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