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routes

Manages AWS Transit Gateway (TGW) route tables, including static routes and route propagation from VPC attachments. Enables controlled routing between VPCs connected to a TGW by configuring TGW route table associations, propagations, and explicit routes as needed.

Usage​

Stack Level: Regional

Here's an example snippet for how to use this component.

components:
  terraform:
    tgw/routes:
      vars:
        transit_gateway_route_table_id: "tgw-rtb-0123456789abcdef0"

        # Static routes for specific CIDR blocks
        static_routes:
          - cidr_block: "10.100.0.0/16"
            attachment_id: "tgw-attach-0123456789abcdef0"

        # Route propagation from VPC attachments
        propagated_routes:
          - attachment_id: "tgw-attach-0123456789abcdef1"

The same configuration using terraform outputs:

components:
  terraform:
    tgw/routes:
      vars:
        transit_gateway_route_table_id: !terraform.output tgw/hub transit_gateway_route_table_id

        # Static routes for specific CIDR blocks
        static_routes:
          - cidr_block: !terraform.output vpc edge-vpc vpc_cidr
            attachment_id: !terraform.output tgw/attachment edge-vpc transit_gateway_attachment_id

        # Route propagation from VPC attachments
        propagated_routes:
          - attachment_id: !terraform.output tgw/attachment app-vpc transit_gateway_attachment_id

Multiple Environment Example​

For environments with multiple routing requirements, here's an example using physical IDs:

components:
  terraform:
    tgw/routes/nonprod:
      metadata:
        component: tgw/routes
      vars:
        transit_gateway_route_table_id: "tgw-rtb-0123456789abcdef1"

        # Static routes for specific destinations
        static_routes:
          - cidr_block: "10.20.0.0/16"
            attachment_id: "tgw-attach-0123456789abcdef2"
          - cidr_block: "10.30.0.0/16"
            attachment_id: "tgw-attach-0123456789abcdef3"

        # Enable route propagation from specific VPCs
        propagated_routes:
          - attachment_id: "tgw-attach-0123456789abcdef4"
          - attachment_id: "tgw-attach-0123456789abcdef5"

The same configuration using terraform outputs:

components:
  terraform:
    tgw/routes/nonprod:
      metadata:
        component: tgw/routes
      vars:
        transit_gateway_route_table_id: !terraform.output tgw/hub transit-use1-nonprod transit_gateway_route_table_id

        # Static routes for specific destinations
        static_routes:
          - cidr_block: !terraform.output vpc dev-use1-edge vpc_cidr
            attachment_id: !terraform.output tgw/attachment dev-use1-edge transit_gateway_attachment_id
          - cidr_block: !terraform.output vpc staging-use1-edge vpc_cidr
            attachment_id: !terraform.output tgw/attachment staging-use1-edge transit_gateway_attachment_id

        # Enable route propagation from specific VPCs
        propagated_routes:
          - attachment_id: !terraform.output tgw/attachment dev-use1-network transit_gateway_attachment_id
          - attachment_id: !terraform.output tgw/attachment staging-use1-network transit_gateway_attachment_id

Variables​

Required Variables​

region (string) required

AWS Region

Optional Variables​

transit_gateway_route_tables optional

List of Transit Gateway route table configurations


Type:

list(object({
transit_gateway_route_table_id = string
routes = list(object({
  attachment_id = string
  propagated    = optional(bool, true)
  associated    = optional(bool, true)
}))
static_routes = optional(list(object({
  cidr_block    = string
  attachment_id = string
  blackhole     = optional(bool, false)
})), [])
}))

Default value: [ ]

Context Variables​

The following variables are defined in the context.tf file of this module and part of the terraform-null-label pattern.

additional_tag_map (map(string)) optional

Additional key-value pairs to add to each map in tags_as_list_of_maps. Not added to tags or id.
This is for some rare cases where resources want additional configuration of tags
and therefore take a list of maps with tag key, value, and additional configuration.


Required: No

Default value: { }

attributes (list(string)) optional

ID element. Additional attributes (e.g. workers or cluster) to add to id,
in the order they appear in the list. New attributes are appended to the
end of the list. The elements of the list are joined by the delimiter
and treated as a single ID element.


Required: No

Default value: [ ]

context (any) optional

Single object for setting entire context at once.
See description of individual variables for details.
Leave string and numeric variables as null to use default value.
Individual variable settings (non-null) override settings in context object,
except for attributes, tags, and additional_tag_map, which are merged.


Required: No

Default value:

{
  "additional_tag_map": {},
  "attributes": [],
  "delimiter": null,
  "descriptor_formats": {},
  "enabled": true,
  "environment": null,
  "id_length_limit": null,
  "label_key_case": null,
  "label_order": [],
  "label_value_case": null,
  "labels_as_tags": [
    "unset"
  ],
  "name": null,
  "namespace": null,
  "regex_replace_chars": null,
  "stage": null,
  "tags": {},
  "tenant": null
}
delimiter (string) optional

Delimiter to be used between ID elements.
Defaults to - (hyphen). Set to "" to use no delimiter at all.


Required: No

Default value: null

descriptor_formats (any) optional

Describe additional descriptors to be output in the descriptors output map.
Map of maps. Keys are names of descriptors. Values are maps of the form
\{<br/> format = string<br/> labels = list(string)<br/> \}
(Type is any so the map values can later be enhanced to provide additional options.)
format is a Terraform format string to be passed to the format() function.
labels is a list of labels, in order, to pass to format() function.
Label values will be normalized before being passed to format() so they will be
identical to how they appear in id.
Default is {} (descriptors output will be empty).


Required: No

Default value: { }

enabled (bool) optional

Set to false to prevent the module from creating any resources
Required: No

Default value: null

environment (string) optional

ID element. Usually used for region e.g. 'uw2', 'us-west-2', OR role 'prod', 'staging', 'dev', 'UAT'
Required: No

Default value: null

id_length_limit (number) optional

Limit id to this many characters (minimum 6).
Set to 0 for unlimited length.
Set to null for keep the existing setting, which defaults to 0.
Does not affect id_full.


Required: No

Default value: null

label_key_case (string) optional

Controls the letter case of the tags keys (label names) for tags generated by this module.
Does not affect keys of tags passed in via the tags input.
Possible values: lower, title, upper.
Default value: title.


Required: No

Default value: null

label_order (list(string)) optional

The order in which the labels (ID elements) appear in the id.
Defaults to ["namespace", "environment", "stage", "name", "attributes"].
You can omit any of the 6 labels ("tenant" is the 6th), but at least one must be present.


Required: No

Default value: null

label_value_case (string) optional

Controls the letter case of ID elements (labels) as included in id,
set as tag values, and output by this module individually.
Does not affect values of tags passed in via the tags input.
Possible values: lower, title, upper and none (no transformation).
Set this to title and set delimiter to "" to yield Pascal Case IDs.
Default value: lower.


Required: No

Default value: null

labels_as_tags (set(string)) optional

Set of labels (ID elements) to include as tags in the tags output.
Default is to include all labels.
Tags with empty values will not be included in the tags output.
Set to [] to suppress all generated tags.
Notes:
The value of the name tag, if included, will be the id, not the name.
Unlike other null-label inputs, the initial setting of labels_as_tags cannot be
changed in later chained modules. Attempts to change it will be silently ignored.


Required: No

Default value:

[
  "default"
]
name (string) optional

ID element. Usually the component or solution name, e.g. 'app' or 'jenkins'.
This is the only ID element not also included as a tag.
The "name" tag is set to the full id string. There is no tag with the value of the name input.


Required: No

Default value: null

namespace (string) optional

ID element. Usually an abbreviation of your organization name, e.g. 'eg' or 'cp', to help ensure generated IDs are globally unique
Required: No

Default value: null

regex_replace_chars (string) optional

Terraform regular expression (regex) string.
Characters matching the regex will be removed from the ID elements.
If not set, "/[^a-zA-Z0-9-]/" is used to remove all characters other than hyphens, letters and digits.


Required: No

Default value: null

stage (string) optional

ID element. Usually used to indicate role, e.g. 'prod', 'staging', 'source', 'build', 'test', 'deploy', 'release'
Required: No

Default value: null

tags (map(string)) optional

Additional tags (e.g. {'BusinessUnit': 'XYZ'}).
Neither the tag keys nor the tag values will be modified by this module.


Required: No

Default value: { }

tenant (string) optional

ID element (Rarely used, not included by default). A customer identifier, indicating who this instance of a resource is for
Required: No

Default value: null

Outputs​

mock

Mock output example for the Cloud Posse Terraform component template

Dependencies​

Requirements​

  • terraform, version: >= 1.0.0
  • aws, version: >= 4.1, < 6.0.0

Providers​

  • aws, version: >= 4.1, < 6.0.0

Modules​

NameVersionSourceDescription
iam_roleslatest../../account-map/modules/iam-rolesn/a
this0.25.0cloudposse/label/nulln/a

Resources​

The following resources are used by this module:

Data Sources​

The following data sources are used by this module: