Module: Lambda@Edge

Submodule which creates Lambda@Edge functions to associate with the CloudFront distribution in the parent module.

Usage

The lambda_function_association output feeds in directly to the variable of the same name in the parent module.

Important: An AWS Provider configured for us-east-1 must be passed to the module, as Lambda@Edge functions must exist in us-east-1. This is the primary reason why these resources exist in a submodule and not in the parent module.

module "lambda_at_edge" {
  source = "cloudposse/cloudfront-s3-cdn/aws//modules/lambda@edge"
  # Cloud Posse recommends pinning every module to a specific version
  # version = "x.x.x"

  functions = {
    ...
  }

  providers = {
    aws = aws.us-east-1
  }

  context = module.this.context
}

Variables

Required Variables

functions required

Lambda@Edge functions to create.

The key of this map is the name label of the Lambda@Edge function.

One of source, source_dir or source_zip should be specified. These variables are mutually exclusive.

source.filename and source.content dictate the name and content of the files that will make up the Lambda function
source, respectively.

source_dir contains path to whole directory that has to be archived.

source_zip contains path to zip file with lambda source.

runtime, handler, memory_size and timeout correspond to the attributes of the same name in the lambda_function
resource. See here for Lambda@Edge function restrictions.

additional_policy contains additional IAM policies for Lambda@Edge function. It's possible to override default policy statement by providing your own statement with LambdaWriteCloudWatchLogs sid.

event_type and include_body correspond to the attributes of the same name in the Lambda Function association block
of the cloudfront_distribution
resource.

Type:

map(object({
source = optional(list(object({
  filename = string
  content  = string
})))
source_dir        = optional(string)
source_zip        = optional(string)
runtime           = string
handler           = string
memory_size       = optional(number, 128)
timeout           = optional(number, 3)
additional_policy = optional(string, "{}")
event_type        = string
include_body      = bool
}))

Optional Variables

destruction_delay (string) optional

The delay, in Golang ParseDuration format, to wait before destroying the Lambda@Edge
functions.

This delay is meant to circumvent Lambda@Edge functions not being immediately deletable following their dissociation from
a CloudFront distribution, since they are replicated to CloudFront Edge servers around the world.

If set to null, no delay will be introduced.

By default, the delay is 20 minutes. This is because it takes about 3 minutes to destroy a CloudFront distribution, and
around 15 minutes until the Lambda@Edge function is available for deletion, in most cases.

For more information, see: https://github.com/hashicorp/terraform-provider-aws/issues/1721.

Default value: "20m"

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

lambda_function_association

The Lambda@Edge function association configuration to pass to var.lambda_function_association in the parent module.

lambda_functions

The Lambda@Edge functions

Dependencies

Requirements

• terraform, version: >= 1.3
• archive, version: >= 2.2.0
• aws, version: >= 5.0
• local, version: >= 1.2
• time, version: >= 0.7.0

Providers

• archive, version: >= 2.2.0
• aws, version: >= 5.0
• local, version: >= 1.2
• time, version: >= 0.7.0

Modules

Name	Version	Source	Description
function_label	0.25.0	cloudposse/label/null	n/a
role	0.19.0	cloudposse/iam-role/aws	n/a
this	0.25.0	cloudposse/label/null	n/a

Resources

The following resources are used by this module:

• aws_lambda_function.default (resource)
• aws_lambda_permission.allow_cloudfront (resource)
• time_sleep.lambda_at_edge_destruction_delay (resource)

Data Sources

The following data sources are used by this module:

• archive_file.lambda_zip (data source)
• aws_iam_policy_document.lambda_write_logs (data source)
• local_file.lambda_zip (data source)