How to fix filename conflicts with image_uri in Terraform

Choose one of the three valid deployment methods for your Lambda function:

1. Zip file from local path: Use filename parameter
- Best for: Simple functions, quick local testing
- Example: filename = "lambda.zip"

2. Container image from ECR: Use image_uri parameter
- Best for: Complex dependencies, Docker-based deployments
- Example: image_uri = "123456789.dkr.ecr.us-east-1.amazonaws.com/my-function:latest"
- Requires: package_type = "Image"

3. Zip file from S3: Use s3_bucket, s3_key, and optionally s3_object_version
- Best for: CI/CD pipelines, shared artifact storage
- Example: s3_bucket = "my-bucket" s3_key = "lambda.zip"

Decide which one matches your deployment workflow.

Delete all parameters except the one you chose. Search your aws_lambda_function resource for:
- filename
- image_uri
- s3_bucket
- s3_key
- s3_object_version

Keep only the deployment method you selected in step 1, and delete the others:

Bad (conflicting):

resource "aws_lambda_function" "example" {
  function_name = "my-function"
  filename      = "lambda.zip"      # DELETE THIS
  image_uri     = "123456...latest" # or DELETE THIS
  role          = aws_iam_role.lambda.arn
}

Good (using filename):

resource "aws_lambda_function" "example" {
  function_name = "my-function"
  filename      = "lambda.zip"
  role          = aws_iam_role.lambda.arn
}

Good (using image_uri):

resource "aws_lambda_function" "example" {
  function_name = "my-function"
  image_uri     = "123456789.dkr.ecr.us-east-1.amazonaws.com/my-function:latest"
  package_type  = "Image"
  role          = aws_iam_role.lambda.arn
}

Run Terraform validate to check for any remaining issues:

terraform validate

If there are no errors, move to the next step. If you still see conflicting arguments errors, ensure you removed all instances of the conflicting parameters.

Depending on your chosen method, add the required companion parameters:

For filename (Zip):

resource "aws_lambda_function" "example" {
  function_name = "my-function"
  filename      = "lambda.zip"
  handler       = "index.handler"  # Required for Zip
  runtime       = "nodejs18.x"     # Required for Zip
  role          = aws_iam_role.lambda.arn
}

For image_uri (Container):

resource "aws_lambda_function" "example" {
  function_name = "my-function"
  image_uri     = "123456789.dkr.ecr.us-east-1.amazonaws.com/my-function:latest"
  package_type  = "Image"  # REQUIRED for image_uri
  role          = aws_iam_role.lambda.arn
}

For S3 (Zip):

resource "aws_lambda_function" "example" {
  function_name = "my-function"
  s3_bucket     = "my-artifact-bucket"
  s3_key        = "lambda.zip"
  handler       = "index.handler"  # Required for Zip
  runtime       = "nodejs18.x"     # Required for Zip
  role          = aws_iam_role.lambda.arn
}

Now that you've selected a single deployment method, test and apply your changes:

terraform plan
terraform apply

The error should no longer appear. If you still see it, double-check that you removed all conflicting parameters from your resource.