terraform-null-label

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 perfer 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.

Usage

Simple Example

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       = "${map("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"]
  }
}

Advanced Example

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       = "${map("BusinessUnit", "ABC")}"
}

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       = "${map("BusinessUnit", "XYZ")}"
}

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}"]
}

Advanced Example 2

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}"]
}

Advanced Example 3

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"]

  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"

  tags = {
    "City"        = "London"
    "Environment" = "Public"
  }
}

module "label3" {
  source = "git::https://github.com/cloudposse/terraform-null-label.git?ref=master"
  name   = "Starfish"
  stage  = "release"

  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 =
  id = release-starfish
  name = starfish
  namespace =
  stage = release
}
label3_context = {
  attributes = []
  delimiter = [-]
  environment = []
  label_order = [namespace environment stage name attributes]
  name = [starfish]
  namespace = []
  stage = [release]
  tags_keys = [Animal Eat Environment Name Namespace Stage]
  tags_values = [Rabbit Carrot  release-starfish  release]
}
label3_tags = {
  Animal = Rabbit
  Eat = Carrot
  Environment =
  Name = release-starfish
  Namespace =
  Stage = release
}

Makefile Targets

Available targets:

  help                                Help screen
  help/all                            Display help for all targets
  help/short                          This help short screen
  lint                                Lint terraform code

Inputs

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 `name`, `namespace`, `stage`, etc.	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, e.g. 'eg' or 'cp'	string	``	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

Outputs

Name	Description
attributes	Normalized attributes
context	Context of this module to pass between other modules
delimiter	Delimiter used in label ID
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

Related Projects

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

License

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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README.md

README.md

terraform-null-label

Usage

Simple Example

Advanced Example

Advanced Example 2

Advanced Example 3

Makefile Targets

Inputs

Outputs

Related Projects

Help

Commercial Support

Community Forum

Contributing

Bug Reports & Feature Requests

Developing

Copyright

License

Trademarks

About

Contributors

Files

README.md

Latest commit

History

README.md

File metadata and controls

terraform-null-label

Usage

Simple Example

Advanced Example

Advanced Example 2

Advanced Example 3

Makefile Targets

Inputs

Outputs

Related Projects

Help

Commercial Support

Community Forum

Contributing

Bug Reports & Feature Requests

Developing

Copyright

License

Trademarks

About

Contributors