How to fix filename conflicts with image_uri in Terraform

TerraformINTERMEDIATEMEDIUMUpdated Dec 30, 2025· 104 views

The aws_lambda_function resource requires mutually exclusive code deployment options. You cannot use both filename and image_uri in the same Lambda function—choose one based on whether you're deploying from a local file, S3, or container image.

Quick fix

Fixes filename conflicts with image_uri

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
}
  1. Identify which deployment method you need
  2. Remove conflicting parameters from your resource
  3. Validate your configuration
  4. Update required fields based on deployment method
terraform — error
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
}
filename conflicts with image_uri

What this error means

Terraform's aws_lambda_function resource supports multiple ways to specify your Lambda function's deployment package, but these options are mutually exclusive. The filename parameter (for local zip files) conflicts with image_uri (for ECR container images), as well as with s3_bucket and s3_key parameters (for S3-hosted packages). Terraform validates that only one deployment method is specified per function resource. This error means you've accidentally configured more than one of these conflicting parameters, which is invalid in Terraform's provider schema.

Typical symptoms

  • Terraform plan or apply fails immediately with conflicting arguments error
  • Error message specifically mentions 'filename' conflicts with 'image_uri'
  • The error appears when you have both parameters defined in your aws_lambda_function block
  • Module or configuration that tries to conditionally set deployment methods fails validation

Common causes

  1. Both filename and image_uri are specified in the same aws_lambda_function resource block
  2. Using ternary operators or conditionals that don't properly evaluate to null for unused parameters (Terraform still sees the attribute as configured)
  3. Copy-pasting example code and forgetting to remove unused deployment parameters
  4. Reusable Terraform modules that try to support multiple deployment types within a single resource block instead of using separate resources
  5. Misconfigured variables that provide values for multiple conflicting parameters

How to fix "filename conflicts with image_uri"

1Identify which deployment method you need

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.

2Remove conflicting parameters from your resource

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):

hcl
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):

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

Good (using image_uri):

hcl
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
}
3Validate your configuration

Run Terraform validate to check for any remaining issues:

bash
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.

4Update required fields based on deployment method

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

For filename (Zip):

hcl
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):

hcl
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):

hcl
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
}
5Plan and apply your changes

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

bash
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.

Advanced notes

For reusable modules supporting multiple deployment methods:

If you're building a Terraform module that needs to support both container images and zip files, you cannot use a single aws_lambda_function resource with conditional parameters. Instead, use separate resources with count or for_each:

hcl
# Module variables
variable "deployment_type" {
  type = string
  validation {
    condition = contains(["zip", "image"], var.deployment_type)
  }
}

# Zip-based Lambda
resource "aws_lambda_function" "zip" {
  count = var.deployment_type == "zip" ? 1 : 0

  function_name = var.function_name
  filename      = var.filename
  handler       = var.handler
  runtime       = var.runtime
  role          = aws_iam_role.lambda.arn
}

# Container-based Lambda
resource "aws_lambda_function" "image" {
  count = var.deployment_type == "image" ? 1 : 0

  function_name = var.function_name
  image_uri     = var.image_uri
  package_type  = "Image"
  role          = aws_iam_role.lambda.arn
}

This pattern separates the conflicting configurations into distinct resource blocks, avoiding the validation error entirely.

Managing image updates with Terraform:

When deploying container images via Terraform, you may want Lambda to auto-update when the image is pushed to ECR. To avoid drift detection issues, consider using lifecycle rules or the ignore_source_code_hash equivalent for images, though these require careful state management.

Frequently asked questions

What does "filename conflicts with image_uri" mean?
Terraform's aws_lambda_function resource supports multiple ways to specify your Lambda function's deployment package, but these options are mutually exclusive. The filename parameter (for local zip files) conflicts with image_uri (for ECR container images), as well as with s3_bucket and s3_key parameters (for S3-hosted packages). Terraform validates that only one deployment method is specified per function resource.
How do I fix "filename conflicts with image_uri"?
The aws_lambda_function resource requires mutually exclusive code deployment options. You cannot use both filename and image_uri in the same Lambda function—choose one based on whether you're deploying from a local file, S3, or container image.
What causes "filename conflicts with image_uri"?
Both filename and image_uri are specified in the same aws_lambda_function resource block Using ternary operators or conditionals that don't properly evaluate to null for unused parameters (Terraform still sees the attribute as configured) Copy-pasting example code and forgetting to remove unused deployment parameters
Is the "filename conflicts with image_uri" error serious?
It is a medium-severity error — more of a blocker than a risk. The steps above resolve it.

Official resources & further reading