Terraform module designed to generate consistent label names and tags for resources. Use terraform-null-label
to implement a strict naming convention.
A label follows the following convention: {namespace}-{environment}-{stage}-{name}-{attributes}
. The delimiter (e.g. -
) is interchangeable.
The label items are all optional. So if you prefer the term stage
to environment
you can exclude environment and the label id
will look like {namespace}-{stage}-{name}-{attributes}
.
If attributes are excluded but stage
and environment
are included, id
will look like {namespace}-{environment}-{stage}-{name}
It's recommended to use one terraform-null-label
module for every unique resource of a given resource type.
For example, if you have 10 instances, there should be 10 different labels.
However, if you have multiple different kinds of resources (e.g. instances, security groups, file systems, and elastic ips), then they can all share the same label assuming they are logically related.
All Cloud Posse modules use this module to ensure resources can be instantiated multiple times within an account and without conflict.
NOTE: The null
refers to the primary Terraform provider used in this module.
This project is part of our comprehensive "SweetOps" approach towards DevOps.
It's 100% Open Source and licensed under the APACHE2.
We literally have hundreds of terraform modules that are Open Source and well-maintained. Check them out!
IMPORTANT: The master
branch is used in source
just as an example. In your code, do not pin to master
because there may be breaking changes between releases.
Instead pin to the release tag (e.g. ?ref=tags/x.y.z
) of one of our latest releases.
module "eg_prod_bastion_label" {
source = "git::https://github.com/cloudposse/terraform-null-label.git?ref=master"
namespace = "eg"
stage = "prod"
name = "bastion"
attributes = ["public"]
delimiter = "-"
tags = {
"BusinessUnit" = "XYZ",
"Snapshot" = "true"
}
}
This will create an id
with the value of eg-prod-bastion-public
because when generating id
, the default order is namespace
, environment
, stage
, name
, attributes
(you can override it by using the label_order
variable, see Advanced Example 3).
Now reference the label when creating an instance:
resource "aws_instance" "eg_prod_bastion_public" {
instance_type = "t1.micro"
tags = "${module.eg_prod_bastion_label.tags}"
}
Or define a security group:
resource "aws_security_group" "eg_prod_bastion_public" {
vpc_id = "${var.vpc_id}"
name = "${module.eg_prod_bastion_label.id}"
tags = "${module.eg_prod_bastion_label.tags}"
egress {
from_port = 0
to_port = 0
protocol = "-1"
cidr_blocks = ["0.0.0.0/0"]
}
}
Here is a more complex example with two instances using two different labels. Note how efficiently the tags are defined for both the instance and the security group.
module "eg_prod_bastion_abc_label" {
source = "git::https://github.com/cloudposse/terraform-null-label.git?ref=master"
namespace = "eg"
stage = "prod"
name = "bastion"
attributes = ["abc"]
delimiter = "-"
tags = {
"BusinessUnit" = "XYZ",
"Snapshot" = "true"
}
}
resource "aws_security_group" "eg_prod_bastion_abc" {
name = "${module.eg_prod_bastion_abc_label.id}"
tags = "${module.eg_prod_bastion_abc_label.tags}"
ingress {
from_port = 22
to_port = 22
protocol = "tcp"
cidr_blocks = ["0.0.0.0/0"]
}
}
resource "aws_instance" "eg_prod_bastion_abc" {
instance_type = "t1.micro"
tags = "${module.eg_prod_bastion_abc_label.tags}"
vpc_security_group_ids = ["${aws_security_group.eg_prod_bastion_abc.id}"]
}
module "eg_prod_bastion_xyz_label" {
source = "git::https://github.com/cloudposse/terraform-null-label.git?ref=master"
namespace = "eg"
stage = "prod"
name = "bastion"
attributes = ["xyz"]
delimiter = "-"
tags = {
"BusinessUnit" = "XYZ",
"Snapshot" = "true"
}
}
resource "aws_security_group" "eg_prod_bastion_xyz" {
name = "${module.eg_prod_bastion_xyz_label.id}"
tags = "${module.eg_prod_bastion_xyz_label.tags}"
ingress {
from_port = 22
to_port = 22
protocol = "tcp"
cidr_blocks = ["0.0.0.0/0"]
}
}
resource "aws_instance" "eg_prod_bastion_xyz" {
instance_type = "t1.micro"
tags = "${module.eg_prod_bastion_xyz_label.tags}"
vpc_security_group_ids = ["${aws_security_group.eg_prod_bastion_xyz.id}"]
}
Here is a more complex example with an autoscaling group that has a different tagging schema than other resources and requires its tags to be in this format, which this module can generate:
tags = [
{
key = Name,
propagate_at_launch = 1,
value = namespace-stage-name
},
{
key = Namespace,
propagate_at_launch = 1,
value = namespace
},
{
key = Stage,
propagate_at_launch = 1,
value = stage
}
]
Autoscaling group using propagating tagging below (full example: autoscalinggroup)
################################
# terraform-null-label example #
################################
module "label" {
source = "../../"
namespace = "cp"
stage = "prod"
name = "app"
tags = {
BusinessUnit = "Finance"
ManagedBy = "Terraform"
}
additional_tag_map = {
propagate_at_launch = "true"
}
}
#######################
# Launch template #
#######################
resource "aws_launch_template" "default" {
# terraform-null-label example used here: Set template name prefix
name_prefix = "${module.label.id}-"
image_id = "${data.aws_ami.amazon_linux.id}"
instance_type = "t2.micro"
instance_initiated_shutdown_behavior = "terminate"
vpc_security_group_ids = ["${data.aws_security_group.default.id}"]
monitoring {
enabled = false
}
# terraform-null-label example used here: Set tags on volumes
tag_specifications {
resource_type = "volume"
tags = "${module.label.tags}"
}
}
######################
# Autoscaling group #
######################
resource "aws_autoscaling_group" "default" {
# terraform-null-label example used here: Set ASG name prefix
name_prefix = "${module.label.id}-"
vpc_zone_identifier = ["${data.aws_subnet_ids.all.ids}"]
max_size = "1"
min_size = "1"
desired_capacity = "1"
launch_template = {
id = "${aws_launch_template.default.id}"
version = "$$Latest"
}
# terraform-null-label example used here: Set tags on ASG and EC2 Servers
tags = ["${module.label.tags_as_list_of_maps}"]
}
See complete example
This example shows how you can pass the context
output of one label module to the next label_module,
allowing you to create one label that has the base set of values, and then creating every extra label
as a derivative of that.
module "label1" {
source = "git::https://github.com/cloudposse/terraform-null-label.git?ref=master"
namespace = "CloudPosse"
environment = "UAT"
stage = "build"
name = "Winston Churchroom"
attributes = ["fire", "water", "earth", "air"]
delimiter = "-"
label_order = ["name", "environment", "stage", "attributes"]
tags = {
"City" = "Dublin"
"Environment" = "Private"
}
}
module "label2" {
source = "git::https://github.com/cloudposse/terraform-null-label.git?ref=master"
context = "${module.label1.context}"
name = "Charlie"
stage = "test"
delimiter = "+"
tags = {
"City" = "London"
"Environment" = "Public"
}
}
module "label3" {
source = "git::https://github.com/cloudposse/terraform-null-label.git?ref=master"
name = "Starfish"
stage = "release"
context = "${module.label1.context}"
delimiter = "."
tags = {
"Eat" = "Carrot"
"Animal" = "Rabbit"
}
}
This creates label outputs like this:
label1 = {
attributes = [fire water earth air]
id = winstonchurchroom-uat-build-fire-water-earth-air
name = winstonchurchroom
namespace = cloudposse
stage = build
}
label1_context = {
attributes = [fire water earth air]
delimiter = [-]
environment = [uat]
label_order = [name environment stage attributes]
name = [winstonchurchroom]
namespace = [cloudposse]
stage = [build]
tags_keys = [City Environment Name Namespace Stage]
tags_values = [Dublin Private winstonchurchroom-uat-build-fire-water-earth-air cloudposse build]
}
label1_tags = {
City = Dublin
Environment = Private
Name = winstonchurchroom-uat-build-fire-water-earth-air
Namespace = cloudposse
Stage = build
}
label2 = {
attributes = [fire water earth air]
id = charlie+uat+test+fire+water+earth+air
name = charlie
namespace = cloudposse
stage = test
}
label2_context = {
attributes = [fire water earth air]
delimiter = [+]
environment = [uat]
label_order = [name environment stage attributes]
name = [charlie]
namespace = [cloudposse]
stage = [test]
tags_keys = [City Environment Name Namespace Stage]
tags_values = [London Public charlie+uat+test+fire+water+earth+air cloudposse test]
}
label2_tags = {
City = London
Environment = Public
Name = charlie+uat+test+fire+water+earth+air
Namespace = cloudposse
Stage = test
}
label3 = {
attributes = [fire water earth air]
id = starfish.uat.release.fire.water.earth.air
name = starfish
namespace = cloudposse
stage = release
}
label3_context = {
attributes = [fire water earth air]
delimiter = [.]
environment = [uat]
label_order = [name environment stage attributes]
name = [starfish]
namespace = [cloudposse]
stage = [release]
tags_keys = [Animal City Eat Environment Name Namespace Stage]
tags_values = [Rabbit Dublin Carrot uat starfish.uat.release.fire.water.earth.air cloudposse release]
}
label3_tags = {
Animal = Rabbit
City = Dublin
Eat = Carrot
Environment = uat
Name = starfish.uat.release.fire.water.earth.air
Namespace = cloudposse
Stage = release
}
Available targets:
help Help screen
help/all Display help for all targets
help/short This help short screen
lint Lint terraform code
Name | Description | Type | Default | Required |
---|---|---|---|---|
additional_tag_map | Additional tags for appending to each tag map | map | <map> |
no |
attributes | Additional attributes (e.g. 1 ) |
list | <list> |
no |
context | Default context to use for passing state between label invocations | map | <map> |
no |
delimiter | Delimiter to be used between namespace , environment , stage , name and attributes |
string | - |
no |
enabled | Set to false to prevent the module from creating any resources | string | true |
no |
environment | Environment, e.g. 'prod', 'staging', 'dev', 'pre-prod', 'UAT' | string | `` | no |
label_order | The naming order of the id output and Name tag | list | <list> |
no |
name | Solution name, e.g. 'app' or 'jenkins' | string | `` | no |
namespace | Namespace, which could be your organization name or abbreviation, e.g. 'eg' or 'cp' | string | `` | no |
regex_replace_chars | Regex to replace chars with empty string in namespace , environment , stage and name . By default only hyphens, letters and digits are allowed, all other chars are removed |
string | /[^a-zA-Z0-9-]/ |
no |
stage | Stage, e.g. 'prod', 'staging', 'dev', OR 'source', 'build', 'test', 'deploy', 'release' | string | `` | no |
tags | Additional tags (e.g. map('BusinessUnit','XYZ') |
map | <map> |
no |
Name | Description |
---|---|
attributes | List of attributes |
context | Context of this module to pass to other label modules |
delimiter | Delimiter between namespace , environment , stage , name and attributes |
environment | Normalized environment |
id | Disambiguated ID |
label_order | The naming order of the id output and Name tag |
name | Normalized name |
namespace | Normalized namespace |
stage | Normalized stage |
tags | Normalized Tag map |
tags_as_list_of_maps | Additional tags as a list of maps, which can be used in several AWS resources |
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Check out these related projects.
- terraform-terraform-label - Terraform Module to define a consistent naming convention by (namespace, environment, stage, name, [attributes])
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Copyright © 2017-2019 Cloud Posse, LLC
See LICENSE for full details.
Licensed to the Apache Software Foundation (ASF) under one
or more contributor license agreements. See the NOTICE file
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regarding copyright ownership. The ASF licenses this file
to you under the Apache License, Version 2.0 (the
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