How to Import an AWS Lambda Function into Terraform

Import AWS Lambda Function with Terraback (recommended)

Terraback reverse-engineers your live infrastructure: it reads the AWS Lambda resource with read-only credentials, generates the HCL, and produces the exact import block. Two commands take you from a live AWS Lambda Function to managed Terraform.

terraback scan all aws --region us-east-1

terraback aws import --method bulk

The Terraform import block

Terraback emits a Terraform 1.5+ import block like the one below. Because the block lives in your configuration, the import is reviewable in a pull request and repeatable across environments.

import {
  to = aws_lambda_function.resizer
  id = "image-resizer"
}

Example aws_lambda_function configuration

Here is a realistic AWS Lambda Function block. Terraback generates a fuller version from your actual resource attributes; this is a minimal, valid starting point.

resource "aws_lambda_function" "resizer" {
  function_name = "image-resizer"
  role          = "arn:aws:iam::123456789012:role/image-resizer-role"
  runtime       = "python3.12"
  handler       = "main.handler"
  filename      = "build/image-resizer.zip"
}

Gotchas when importing a AWS Lambda Function

• The deployment package is not downloaded on import; point filename or s3_bucket/s3_key at your own artifact and expect a source_code_hash diff on the first apply.
• Deprecated runtimes may be normalized by the provider; confirm the runtime value matches a currently supported identifier.
• Environment variables import as plain text, including anything sensitive; move secrets to references after import.
• Event source mappings, permissions, and aliases are separate resources.

Doing it manually with terraform import

The native approach is to write the aws_lambda_function block by hand, then run terraform import aws_lambda_function.example <import-id> for every resource, one at a time. That works for a handful of resources, but it does not scale: you author all the HCL yourself and repeat the command for each item. Terraback generates the HCL and the import blocks for your whole account in one pass.

Import other AWS resources