contributing.md

Developer Documentation

Outputs Methodology

This module organizes outputs by creating output collections of grouped entire resources. The benefit of this is that, most likely, attributes users want access to are already present without having to create new output {} for each possible attribute. The [potential] downside is that you will have to extract it yourself using HCL logic. See the outputs.tf for examples.

Our naming convetion attempts to make the output content clear. route_table_attributes_by_type_by_az is a nested map of route table resource attributes grouped by their subnet type then by the az. Example:

route_table_attributes_by_type_by_az = {
  "private" = {
    "us-east-1a" = {
      "id" = "rtb-0e77040c0598df003"
      "route_table_id" = "rtb-0e77040c0598df003"
      "tags" = tolist([
        {
          "key" = "Name"
          "value" = "private-us-east-1a"
        },
      ])
      "vpc_id" = "vpc-033e054f49409592a"
    }
    "us-east-1b" = {
      ...
    }
  "public" = { ... }

Adding new subnet types

Note: All subnet types MUST accept both cidrs and netmask arguments.

1. Updates to variables.tf

   1. Add new to subnets key variable validation:

      validation {
        error_message = "Only valid key values \"public\", \"private\", or \"transit_gateway\"."
        condition = length(setsubtract(keys(var.subnets), [
          "public",
          "private",
          "transit_gateway",
          "<new type here>"
        ])) == 0
      }

   2. Specify keys allowed in new variable type map. Copy an existing one and edit the keys to match what you expect users to input:

      # All var.subnets.public valid keys
      validation {
        error_message = "Invalid key in public subnets. Valid options include: \"cidrs\", \"netmask\", \"name_prefix\", \"nat_gateway_configuration\", \"tags\"."
        condition = length(setsubtract(keys(try(var.subnets.public, {})), [
            "cidrs",
            "netmask",
            "name_prefix",
            "nat_gateway_configuration",
            "tags"
        ])) == 0
      }

   3. Include in description:

        **private subnet type options:**
          - All shared keys above
          - `connect_to_public_natgw`  = (Optional|bool) <>

2. Write configuration code

Note: each for_each loop must account for if a user does not want to create the particular subnet type. Follow examples from other subnet types in main.tf

* Create new `aws_subnet`
* Create new `aws_route_table`
* Create new `aws_route_table_association`
* Consider and create appropriate `aws_route`

3. Create appropriate outputs

   1. output "<new subnet type>_subnet_attributes_by_az"
   2. add new type to route_table_attributes_by_type_by_az