feat: Added ability to specify CloudWatch Log group name for VPC Flow logs (#847)

Co-authored-by: Anton Babenko <anton@antonbabenko.com>

README.md

@@ -435,6 +435,7 @@ No modules.
 | <a name="input_flow_log_cloudwatch_iam_role_arn"></a> [flow\_log\_cloudwatch\_iam\_role\_arn](#input\_flow\_log\_cloudwatch\_iam\_role\_arn) | The ARN for the IAM role that's used to post flow logs to a CloudWatch Logs log group. When flow\_log\_destination\_arn is set to ARN of Cloudwatch Logs, this argument needs to be provided. | `string` | `""` | no |
 | <a name="input_flow_log_cloudwatch_log_group_kms_key_id"></a> [flow\_log\_cloudwatch\_log\_group\_kms\_key\_id](#input\_flow\_log\_cloudwatch\_log\_group\_kms\_key\_id) | The ARN of the KMS Key to use when encrypting log data for VPC flow logs. | `string` | `null` | no |
 | <a name="input_flow_log_cloudwatch_log_group_name_prefix"></a> [flow\_log\_cloudwatch\_log\_group\_name\_prefix](#input\_flow\_log\_cloudwatch\_log\_group\_name\_prefix) | Specifies the name prefix of CloudWatch Log Group for VPC flow logs. | `string` | `"/aws/vpc-flow-log/"` | no |
+| <a name="input_flow_log_cloudwatch_log_group_name_suffix"></a> [flow\_log\_cloudwatch\_log\_group\_name\_suffix](#input\_flow\_log\_cloudwatch\_log\_group\_name\_suffix) | Specifies the name suffix of CloudWatch Log Group for VPC flow logs. | `string` | `""` | no |
 | <a name="input_flow_log_cloudwatch_log_group_retention_in_days"></a> [flow\_log\_cloudwatch\_log\_group\_retention\_in\_days](#input\_flow\_log\_cloudwatch\_log\_group\_retention\_in\_days) | Specifies the number of days you want to retain log events in the specified log group for VPC flow logs. | `number` | `null` | no |
 | <a name="input_flow_log_destination_arn"></a> [flow\_log\_destination\_arn](#input\_flow\_log\_destination\_arn) | The ARN of the CloudWatch log group or S3 bucket where VPC Flow Logs will be pushed. If this ARN is a S3 bucket the appropriate permissions need to be set on that bucket's policy. When create\_flow\_log\_cloudwatch\_log\_group is set to false this argument must be provided. | `string` | `""` | no |
 | <a name="input_flow_log_destination_type"></a> [flow\_log\_destination\_type](#input\_flow\_log\_destination\_type) | Type of flow log destination. Can be s3 or cloud-watch-logs. | `string` | `"cloud-watch-logs"` | no |

examples/vpc-flow-logs/main.tf

@@ -67,7 +67,10 @@ module "vpc_with_flow_logs_cloudwatch_logs_default" {
   enable_flow_log                      = true
   create_flow_log_cloudwatch_log_group = true
   create_flow_log_cloudwatch_iam_role  = true
-  flow_log_max_aggregation_interval    = 60
+
+  flow_log_max_aggregation_interval         = 60
+  flow_log_cloudwatch_log_group_name_prefix = "/aws/my-amazing-vpc-flow-logz/"
+  flow_log_cloudwatch_log_group_name_suffix = "my-test"
 
   vpc_flow_log_tags = local.tags
 }

variables.tf

@@ -1167,6 +1167,12 @@ variable "flow_log_cloudwatch_log_group_name_prefix" {
   default     = "/aws/vpc-flow-log/"
 }
 
+variable "flow_log_cloudwatch_log_group_name_suffix" {
+  description = "Specifies the name suffix of CloudWatch Log Group for VPC flow logs."
+  type        = string
+  default     = ""
+}
+
 variable "flow_log_cloudwatch_log_group_retention_in_days" {
   description = "Specifies the number of days you want to retain log events in the specified log group for VPC flow logs."
   type        = number

vpc-flow-logs.tf

@@ -5,8 +5,9 @@ locals {
   create_flow_log_cloudwatch_iam_role  = local.enable_flow_log && var.flow_log_destination_type != "s3" && var.create_flow_log_cloudwatch_iam_role
   create_flow_log_cloudwatch_log_group = local.enable_flow_log && var.flow_log_destination_type != "s3" && var.create_flow_log_cloudwatch_log_group
 
-  flow_log_destination_arn = local.create_flow_log_cloudwatch_log_group ? try(aws_cloudwatch_log_group.flow_log[0].arn, null) : var.flow_log_destination_arn
-  flow_log_iam_role_arn    = var.flow_log_destination_type != "s3" && local.create_flow_log_cloudwatch_iam_role ? try(aws_iam_role.vpc_flow_log_cloudwatch[0].arn, null) : var.flow_log_cloudwatch_iam_role_arn
+  flow_log_destination_arn                  = local.create_flow_log_cloudwatch_log_group ? try(aws_cloudwatch_log_group.flow_log[0].arn, null) : var.flow_log_destination_arn
+  flow_log_iam_role_arn                     = var.flow_log_destination_type != "s3" && local.create_flow_log_cloudwatch_iam_role ? try(aws_iam_role.vpc_flow_log_cloudwatch[0].arn, null) : var.flow_log_cloudwatch_iam_role_arn
+  flow_log_cloudwatch_log_group_name_suffix = var.flow_log_cloudwatch_log_group_name_suffix == "" ? local.vpc_id : var.flow_log_cloudwatch_log_group_name_suffix
 }
 
 ################################################################################
@@ -44,7 +45,7 @@ resource "aws_flow_log" "this" {
 resource "aws_cloudwatch_log_group" "flow_log" {
   count = local.create_flow_log_cloudwatch_log_group ? 1 : 0
 
-  name              = "${var.flow_log_cloudwatch_log_group_name_prefix}${local.vpc_id}"
+  name              = "${var.flow_log_cloudwatch_log_group_name_prefix}${local.flow_log_cloudwatch_log_group_name_suffix}"
   retention_in_days = var.flow_log_cloudwatch_log_group_retention_in_days
   kms_key_id        = var.flow_log_cloudwatch_log_group_kms_key_id