Merge pull request #66 from ajschofield/alex/tf-improvements

pr: terraform improvements

1 files changed, 59 insertions, 32 deletions

diff --git a/terraform/lambda.tf b/terraform/lambda.tf
index 72aae04..f8e7515 100644
--- a/terraform/lambda.tf
+++ b/terraform/lambda.tf
@@ -1,4 +1,54 @@
-# Extract Lambda Function
+####################
+# Common Variables #
+####################
+
+locals {
+  layer_dir      = "../"
+  layer_zip      = "layer.zip"
+  layer_name     = "lambda_layer"
+  script_dir     = "../scripts"
+  layer_zip_path = "${local.layer_dir}/${local.layer_zip}"
+}
+
+######################
+# Lambda Layer Setup #
+######################
+
+resource "null_resource" "prepare_layer" {
+
+  # New change: only run the script if the layer zip does not exist
+
+  triggers = {
+    layer_zip_exists = fileexists(local.layer_zip_path) ? "exists" : "not_exists"
+  }
+
+  provisioner "local-exec" {
+    command = "if [ ! -f ${local.layer_zip_path} ]; then bash ${local.script_dir}/make_layer_zip.sh; fi"
+  }
+}
+
+resource "aws_s3_object" "lambda_layer_zip" {
+  bucket     = aws_s3_bucket.lambda_code_bucket.id #bucket instead of id
+  key        = "${local.layer_name}/${local.layer_zip}"
+  source     = "${local.layer_dir}/${local.layer_zip}"
+  depends_on = [null_resource.prepare_layer]
+  etag       = fileexists(local.layer_zip_path) ? filemd5(local.layer_zip_path) : null
+}
+
+resource "aws_lambda_layer_version" "lambda_layer" {
+  layer_name          = local.layer_name
+  compatible_runtimes = ["python3.11"]
+  s3_bucket           = aws_s3_bucket.lambda_code_bucket.bucket
+  s3_key              = aws_s3_object.lambda_layer_zip.key
+  source_code_hash    = fileexists(local.layer_zip_path) ? filebase64sha256(local.layer_zip_path) : null
+  skip_destroy        = true
+  depends_on          = [aws_s3_object.lambda_layer_zip]
+}
+
+###########################
+# Extract Lambda Function #
+###########################
+
 data "archive_file" "extract_lambda_zip" {
   type        = "zip"
   source_file = "${path.module}/../src/extract_lambda.py"
@@ -28,7 +78,10 @@ resource "aws_lambda_function" "extract_lambda" {
   depends_on = [aws_s3_object.extract_lambda_code]
 }
 
-# Transform Lambda Function
+#############################
+# Transform Lambda Function #
+#############################
+
 data "archive_file" "transform_lambda_zip" {
   type        = "zip"
   source_file = "${path.module}/../src/transform_lambda.py"
@@ -58,7 +111,10 @@ resource "aws_lambda_function" "transform_lambda" {
   depends_on = [aws_s3_object.transform_lambda_code]
 }
 
-# Load Lambda Function
+########################
+# Load Lambda Function #
+########################
+
 data "archive_file" "load_lambda_zip" {
   type        = "zip"
   source_file = "${path.module}/../src/load_lambda.py"
@@ -88,32 +144,3 @@ resource "aws_lambda_function" "load_lambda" {
   depends_on = [aws_s3_object.load_lambda_code]
 }
 
-# Lambda Layer Specification
-locals {
-  layer_dir  = "../"
-  layer_zip  = "layer.zip"
-  layer_name = "lambda_layer"
-  script_dir = "../scripts"
-}
-
-resource "null_resource" "prepare_layer" {
-  provisioner "local-exec" {
-    command = "bash ${local.script_dir}/make_layer_zip.sh"
-  }
-}
-
-resource "aws_s3_object" "lambda_layer_zip" {
-  bucket     = aws_s3_bucket.lambda_code_bucket.id #bucket instead of id
-  key        = "${local.layer_name}/${local.layer_zip}"
-  source     = "${local.layer_dir}/${local.layer_zip}"
-  depends_on = [null_resource.prepare_layer]
-}
-
-resource "aws_lambda_layer_version" "lambda_layer" {
-  layer_name          = local.layer_name
-  compatible_runtimes = ["python3.11"]
-  s3_bucket           = aws_s3_bucket.lambda_code_bucket.bucket
-  s3_key              = aws_s3_object.lambda_layer_zip.key
-  skip_destroy        = true
-  depends_on          = [aws_s3_object.lambda_layer_zip]
-}