From ece54bbb62ff0645b597eebdf8591ac925c0cba4 Mon Sep 17 00:00:00 2001
From: Karol Czeryna <k@e-dot.uk>
Date: Tue, 8 Jun 2021 16:32:36 +0100
Subject: [PATCH] NLB Log Delivery Support

---
 README.md    | 18 ++++++++++++++++++
 main.tf      | 54 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 variables.tf |  6 ++++++
 3 files changed, 77 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 97bae96e..a2438d32 100644
--- a/README.md
+++ b/README.md
@@ -13,6 +13,7 @@ These features of S3 bucket configurations are supported:
 - object locking
 - Cross-Region Replication (CRR)
 - ELB log delivery bucket policy
+- NLB log delivery bucket policy
 
 ## Usage
 
@@ -48,6 +49,22 @@ module "s3_bucket_for_logs" {
 }
 ```
 
+### Bucket with NLB access log delivery policy attached
+
+```hcl
+module "s3_bucket_for_logs" {
+  source = "terraform-aws-modules/s3-bucket/aws"
+
+  bucket = "my-s3-bucket-for-logs"
+  acl    = "log-delivery-write"
+
+  # Allow deletion of non-empty bucket
+  force_destroy = true
+
+  attach_nlb_log_delivery_policy = true
+}
+```
+
 ## Conditional creation
 
 Sometimes you need to have a way to create S3 resources conditionally but Terraform does not allow to use `count` inside `module` block, so the solution is to specify argument `create_bucket`.
@@ -122,6 +139,7 @@ No modules.
 | <a name="input_acl"></a> [acl](#input\_acl) | (Optional) The canned ACL to apply. Defaults to 'private'. Conflicts with `grant` | `string` | `"private"` | no |
 | <a name="input_attach_deny_insecure_transport_policy"></a> [attach\_deny\_insecure\_transport\_policy](#input\_attach\_deny\_insecure\_transport\_policy) | Controls if S3 bucket should have deny non-SSL transport policy attached | `bool` | `false` | no |
 | <a name="input_attach_elb_log_delivery_policy"></a> [attach\_elb\_log\_delivery\_policy](#input\_attach\_elb\_log\_delivery\_policy) | Controls if S3 bucket should have ELB log delivery policy attached | `bool` | `false` | no |
+| <a name="input_attach_nlb_log_delivery_policy"></a> [attach\_nlb\_log\_delivery\_policy](#input\_attach\_elb\_log\_delivery\_policy) | Controls if S3 bucket should have NLB log delivery policy attached | `bool` | `false` | no |
 | <a name="input_attach_policy"></a> [attach\_policy](#input\_attach\_policy) | Controls if S3 bucket should have bucket policy attached (set to `true` to use value of `policy` as bucket policy) | `bool` | `false` | no |
 | <a name="input_attach_public_policy"></a> [attach\_public\_policy](#input\_attach\_public\_policy) | Controls if a user defined public bucket policy will be attached (set to `false` to allow upstream to apply defaults to the bucket) | `bool` | `true` | no |
 | <a name="input_block_public_acls"></a> [block\_public\_acls](#input\_block\_public\_acls) | Whether Amazon S3 should block public ACLs for this bucket. | `bool` | `false` | no |
diff --git a/main.tf b/main.tf
index 77a4c94a..786adcc3 100644
--- a/main.tf
+++ b/main.tf
@@ -1,5 +1,5 @@
 locals {
-  attach_policy = var.attach_elb_log_delivery_policy || var.attach_deny_insecure_transport_policy || var.attach_policy
+  attach_policy = var.attach_elb_log_delivery_policy || var.attach_nlb_log_delivery_policy || var.attach_deny_insecure_transport_policy || var.attach_policy
 }
 
 resource "aws_s3_bucket" "this" {
@@ -247,6 +247,7 @@ data "aws_iam_policy_document" "combined" {
 
   source_policy_documents = compact([
     var.attach_elb_log_delivery_policy ? data.aws_iam_policy_document.elb_log_delivery[0].json : "",
+    var.attach_nlb_log_delivery_policy ? data.aws_iam_policy_document.nlb_log_delivery[0].json : "",
     var.attach_deny_insecure_transport_policy ? data.aws_iam_policy_document.deny_insecure_transport[0].json : "",
     var.attach_policy ? var.policy : ""
   ])
@@ -280,6 +281,57 @@ data "aws_iam_policy_document" "elb_log_delivery" {
   }
 }
 
+# NLB 
+
+data "aws_iam_policy_document" "nlb_log_delivery" {
+  count = var.create_bucket && var.attach_nlb_log_delivery_policy ? 1 : 0
+
+  statement {
+    sid = "AWSLogDeliveryWrite"
+
+    principals {
+      type        = "Service"
+      identifiers = ["delivery.logs.amazonaws.com"]
+    }
+
+    effect = "Allow"
+
+    actions = [
+      "s3:PutObject",
+    ]
+
+    resources = [
+      "${aws_s3_bucket.this[0].arn}/*",
+    ]
+
+    condition {
+      test  = "StringEquals"
+      variable = "s3:x-amz-acl"
+      values = ["bucket-owner-full-control"]
+    }
+  }
+
+  statement {
+    sid = "AWSLogDeliveryAclCheck"
+
+    effect = "Allow"
+
+    principals {
+      type        = "Service"
+      identifiers = ["delivery.logs.amazonaws.com"]
+    }
+
+    actions = [
+      "s3:GetBucketAcl",
+    ]
+
+    resources = [
+      "${aws_s3_bucket.this[0].arn}",
+    ]
+
+  }
+}
+
 data "aws_iam_policy_document" "deny_insecure_transport" {
   count = var.create_bucket && var.attach_deny_insecure_transport_policy ? 1 : 0
 
diff --git a/variables.tf b/variables.tf
index f07d4169..ba1f8bbf 100644
--- a/variables.tf
+++ b/variables.tf
@@ -10,6 +10,12 @@ variable "attach_elb_log_delivery_policy" {
   default     = false
 }
 
+variable "attach_nlb_log_delivery_policy" {
+  description = "Controls if S3 bucket should have NLB log delivery policy attached"
+  type        = bool
+  default     = false
+}
+
 variable "attach_deny_insecure_transport_policy" {
   description = "Controls if S3 bucket should have deny non-SSL transport policy attached"
   type        = bool