terraform to conditionally create ECR repository if not exists - amazon-web-services

Question

I am using terraform to deploy my resources. I have a terraform code to create a ECR repository here:
resource "aws_ecr_repository" "main" {
name = var.repo_name
image_tag_mutability = var.image_tag_mutability
image_scanning_configuration {
scan_on_push = true
}
}
The above code works fine. However, if the ECR repository already exists in AWS, it throws the error.
For the solution, I wanted to use the terraform data statement to query if the repository exists:
data "aws_ecr_repository" "repository" {
name = var.repo_name
}
resource "aws_ecr_repository" "main" {
name = data.aws_ecr_repository.repository.name
image_tag_mutability = var.image_tag_mutability
image_scanning_configuration {
scan_on_push = true
}
}
It's throwing error like this:
Error: ECR Repository (digital-service) not found
Any suggestions are appreciated.

Answer 1

For future references, you can check and create resources conditionally using the external resource data, in my case i need to createone repo for development images in one repository and i was using docker provider to build and push the image to that ecr
main.tf
terraform {
required_version = ">= 1.3.0"
# Set the required provider
required_providers {
docker = {
source = "kreuzwerker/docker"
version = "2.15.0"
}
}
}
# Creating a repository in ECR
resource "aws_ecr_repository" "repository" {
count = data.external.check_repo.result.success == "true" ? 0 : 1
name = var.repository_name
force_delete = var.force_delete_repo
}
# Build and Push an image to ECR
resource "docker_registry_image" "image" {
name = length(aws_ecr_repository.repository) > 0 ? "${aws_ecr_repository.repository[0].repository_url}:v${var.image_tag}" : "${data.external.check_repo.result.repository_url}:v${var.image_tag}"
insecure_skip_verify = true
build {
context = var.docker_context_url
dockerfile = var.dockerfile_name
build_args = var.docker_build_args
auth_config {
host_name = var.registry_host_name
user_name = var.registry_user
password = var.registry_token
}
}
}
data.tf
data "external" "check_repo" {
program = ["/usr/bin/bash", "${path.module}/script.sh", var.repository_name, var.region]
}
script.sh
#!/bin/bash
result=$(aws ecr describe-repositories --repository-names $1 --region $2 2>&1)
if [ $? -eq 0 ]; then
repository_url=$(echo $result | jq -r '.repositories[0].repositoryUri')
echo -n "{\"success\":\"true\", \"repository_url\":\"$repository_url\", \"name\":\"$1\"}"
else
error_message=$(echo $result | jq -R -s -c '.')
echo -n "{\"success\":\"false\", \"error_message\": $error_message , \"name\":\"$1\"}"
fi
so what we are doing here is checking if the aws_ecr_repository resource have count of 1 which means that the repository does not exist and we are creating it here so we use that resource output, if the repo does exist so the count will be 0 and the we will use the url from the reponse that we got in data.tf external datasource