feat(vpc): add enable_s3_gateway_endpoint variable (#168)

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### Motivation

Add new variable enable_s3_gateway_endpoint

### Modifications

- New variable `enable_s3_gateway_endpoint`

### Verifying this change

- [x] Make sure that the change passes the CI checks.

*(Please pick either of the following options)*

This change is a trivial rework / code cleanup without any test
coverage.

*(or)*

This change is already covered by existing tests, such as *(please
describe tests)*.

*(or)*

This change added tests and can be verified as follows:

*(example:)*
- *Added integration tests for end-to-end deployment with large payloads
(10MB)*
  - *Extended integration test for recovery after broker failure*

### Documentation


- [x] `doc` 
  
  (If this PR contains doc changes)

Signed-off-by: Max Xu <[email protected]>

Author: maxsxu

modules/vpc/README.md

@@ -72,6 +72,7 @@ No modules.
 |------|-------------|------|---------|:--------:|
 | <a name="input_availability_zones"></a> [availability\_zones](#input\_availability\_zones) | The availability zones to provision. If specified will ignore num\_azs | `list(string)` | `[]` | no |
 | <a name="input_disable_nat_gateway"></a> [disable\_nat\_gateway](#input\_disable\_nat\_gateway) | If set to true, will not create NAT Gateway and EC2 Nodes should put in public subnets. This could be useful when wanna save costs from nat gateway. | `bool` | `false` | no |
+| <a name="input_enable_s3_gateway_endpoint"></a> [enable\_s3\_gateway\_endpoint](#input\_enable\_s3\_gateway\_endpoint) | If set to true, will create S3 VPC Endpoint. This could be useful when wanna save costs from NAT Gateway. | `bool` | `false` | no |
 | <a name="input_num_azs"></a> [num\_azs](#input\_num\_azs) | The number of availability zones to provision | `number` | `2` | no |
 | <a name="input_private_subnet_newbits"></a> [private\_subnet\_newbits](#input\_private\_subnet\_newbits) | The number of bits to added to the VPC CIDR prefix. For instance, if your VPC CIDR is a /16 and you set this number to 4, the subnets will be /20s. | `number` | `4` | no |
 | <a name="input_private_subnet_start"></a> [private\_subnet\_start](#input\_private\_subnet\_start) | The starting octet for the private subnet CIDR blocks generated by this module. | `number` | `0` | no |

modules/vpc/main.tf

@@ -145,7 +145,7 @@ resource "aws_route_table_association" "private_assoc" {
 }
 
 resource "aws_vpc_endpoint" "s3_gateway_endpoint" {
-  count = var.disable_nat_gateway ? 0 : 1
+  count = var.disable_nat_gateway || !var.enable_s3_gateway_endpoint ? 0 : 1
 
   vpc_id            = aws_vpc.vpc.id
   service_name      = format("com.amazonaws.%s.s3", var.region)

modules/vpc/variables.tf

@@ -82,3 +82,9 @@ variable "disable_nat_gateway" {
   default     = false
   description = "If set to true, will not create NAT Gateway and EC2 Nodes should put in public subnets. This could be useful when wanna save costs from nat gateway."
 }
+
+variable "enable_s3_gateway_endpoint" {
+  type        = bool
+  default     = false
+  description = "If set to true, will create S3 VPC Endpoint. This could be useful when wanna save costs from NAT Gateway."
+}