AWS Lambda

Invokes an AWS lambda for each message. The contents of the message is the payload of the request, and the result of the invocation will become the new contents of the message.

Common

# Common config fields, showing default values
label: ""
aws_lambda:
  parallel: false
  function: "" # No default (required)

Advanced

# All config fields, showing default values
label: ""
aws_lambda:
  parallel: false
  function: "" # No default (required)
  rate_limit: ""
  region: ""
  endpoint: ""
  credentials:
    profile: ""
    id: ""
    secret: ""
    token: ""
    from_ec2_role: false
    role: ""
    role_external_id: ""
  timeout: 5s
  retries: 3

The rate_limit field can be used to specify a rate limit resourceto cap the rate of requests across parallel components service wide.

In order to map or encode the payload to a specific request body mand map the response back into the original payload instead of replacing it entirely, you can use the branch processor.

Error Handling

When Tyk Streams is unable to connect to the AWS endpoint or is otherwise unable to invoke the target lambda function it will retry the request according to the configured number of retries. Once these attempts have been exhausted the failed message will continue through the pipeline with it’s contents unchanged, but flagged as having failed, allowing you to use standard processor error handling patterns.

However, if the invocation of the function is successful but the function itself throws an error, then the message will have it’s contents updated with a JSON payload describing the reason for the failure, and a metadata field lambda_function_error will be added to the message allowing you to detect and handle function errors with a branch:

pipeline:
  processors:
    - branch:
        processors:
          - aws_lambda:
              function: foo
        result_map: |
          root = if meta().exists("lambda_function_error") {
            throw("Invocation failed due to %v: %v".format(this.errorType, this.errorMessage))
          } else {
            this
          }          
output:
  switch:
    retry_until_success: false
    cases:
      - check: errored()
        output:
          reject: ${! error() }
      - output:
          resource: somewhere_else

Credentials

By default Tyk Streams will use a shared credentials file when connecting to AWS services. It’s also possible to set them explicitly at the component level, allowing you to transfer data across accounts.

Examples

Branched Invoke

This example uses a branch to map a new payload for triggering a lambda function with an ID and username from the original message, and the result of the lambda is discarded, meaning the original message is unchanged.

pipeline:
  processors:
    - branch:
        request_map: '{"id":this.doc.id,"username":this.user.name}'
        processors:
          - aws_lambda:
              function: trigger_user_update

Fields

parallel

Whether messages of a batch should be dispatched in parallel.

Type: bool
Default: false

function

The function to invoke.

Type: string

rate_limit

An optional rate_limit to throttle invocations by.

Type: string
Default: ""

region

The AWS region to target.

Type: string
Default: ""

endpoint

Allows you to specify a custom endpoint for the AWS API.

Type: string
Default: ""

credentials

Optional manual configuration of AWS credentials to use.

Type: object

credentials.profile

A profile from ~/.aws/credentials to use.

Type: string
Default: ""

credentials.id

The ID of credentials to use.

Type: string
Default: ""

credentials.secret

The secret for the credentials being used.

Type: string
Default: ""

credentials.token

The token for the credentials being used, required when using short term credentials.

Type: string
Default: ""

credentials.from_ec2_role

Use the credentials of a host EC2 machine configured to assume an IAM role associated with the instance.

Type: bool
Default: false

credentials.role

A role ARN to assume.

Type: string
Default: ""

credentials.role_external_id

An external ID to provide when assuming a role.

Type: string
Default: ""

timeout

The maximum period of time to wait before abandoning an invocation.

Type: string
Default: "5s"

retries

The maximum number of retry attempts for each message.

Type: int
Default: 3