I have defined the following Terraform module:
module "lambda" {
source = "../lambda"
region = "us-west-1"
account = "${var.account}"
}
How can I take advantage from the module name to set the source parameter with an interpolation? I wish something like:
module "lambda" {
source = "../${this.name}"
region = "us-west-1"
account = "${var.account}"
}
locals {
module = basename(abspath(path.module))
}
{
...
some-id = local.module
...
}
I think is not possible. There's a self that allows you to reference attributes within your resource, but the identifier is not an attribute. Also, self is only allowed within provisioners.
I guess the only way to accomplish what you want is templating the .tf files, like:
module {{ my-module}} {
source = "../{{ my-module }}"
region = "us-west-1"
account = "${var.account}"
but you should render the templates before terraform init. It's straightforward to setup in a CI pipeline, but I find it cumbersome when working locally.
Related
I have a terraform plan that defines most of my BQ environment.
I'm working on a cross-region deployment which will replicate some of my tables to multiple regions.
Rather than copy pasting the same module in every place that I need it at, I'd like to define the module in one place and just call that on every configuration that needs it.
Example I have the following file structure
./cross_region_tables
-> tables.tf
./foo
-> tables.tf
./bar
-> tables.tf
I'd like to define some_module in ./cross_region_tables/tables.tf like so
output "some_module" {
x = something
region = var.region
}
Then I'd like just call some_module from ./foo/tables.tf
The problem is that I don't know how to call this specific module, since ./cross_region_tables/tables.tf will contain several table definitions (as output objects). I know how to import a child module, but I don't know how to call a specific output within that child module
I've solved the issue by adding a module object to the child module with a variable for the region, then calling the child from each regional configuration and passing the region as a variable.
in child folder main.tf:
variable "region" = {}
module "foo" {
x = "something"
y = "something_else"
region = var.region
}
in regional folder for regionX
variable "region" = {
default = regionX
}
module "child" {
source = "../path/to/child"
region = var.region
}
in regional folder for regionY
variable "region" = {
default = regionY
}
module "child" {
source = "../path/to/child"
region = var.region
}
repeat for as many regions as necessary.
You can pass the provider to your modules and each provider with a different
region...
That is well documented here:
https://www.terraform.io/language/modules/develop/providers#passing-providers-explicitly
# The default "aws" configuration is used for AWS resources in the root
# module where no explicit provider instance is selected.
provider "aws" {
region = "us-west-1"
}
# An alternate configuration is also defined for a different
# region, using the alias "usw2".
provider "aws" {
alias = "usw2"
region = "us-west-2"
}
# An example child module is instantiated with the alternate configuration,
# so any AWS resources it defines will use the us-west-2 region.
module "example" {
source = "./example"
providers = {
aws = aws.usw2
}
}
The other part is what you mentioned:
The problem is that I don't know how to call this specific module, since ./cross_region_tables/tables.tf will contain several table definitions
Resources within that module (cross_region_tables) can be turned off/on with variables
I have a use case where I need two AWS providers for different resources. The default aws provider is configured in the main module which uses another module that defines the additional aws provider.
By default, I'd like both providers to use the same AWS credentials unless explicitly overridden.
I figured I could do something like this. In the main module:
locals {
foo_cloud_access_key = aws.access_key
foo_cloud_secret_key = aws.secret_key
}
variable "foo_cloud_access_key" {
type = string
default = local.foo_cloud_access_key
}
variable "foo_cloud_secret_key" {
type = string
default = local.foo_cloud_secret_key
}
where variables foo_cloud_secret_key and foo_cloud_access_key would then be passed down to the child module like this:
module foobar {
...
foobar_access_key = var.foo_cloud_access_key
foobar_secret_key = var.foo_cloud_secret_key
...
}
Where module foobar would then configure its additional was provide with these variables:
provider "aws" {
alias = "foobar_aws"
access_key = var.foobar_access_key
secret_key = var.foobar_secret_key
}
When I run the init terraform spits out this error (for both variables):
Error: Variables not allowed
on variables.tf line 66, in variable "foo_cloud_access_key":
66: default = local.foo_cloud_access_key
Variables may not be used here.
Is it possible to achieve something like this in terraform or is there any other way to go about this?
Having complex, computed default values of variables is possible, but only with a workaround:
define a dummy default value for the variable, e.g. null
define a local variable, its value is either the value of the variable or the actual default value
variable "something" {
default = null
}
locals {
some_computation = ... # based on whatever data you want
something = var.something == null ? local.some_computation : var.something
}
And then only only use local.something instead of var.something in the rest of the terraform files.
I have a terraform project I am working on. In it, I want a file to contain many variables. I want these variables to be accessible from any module of the project. I have looked in the docs and on a udemy course but still don't see how to do this. How does one do this in terraform? Thanks!
I don't think this is possible. There are several discussions about this at Github, but this is not something the Hashicorp team wants.
In general we're against the particular solution of Global Variables, since it makes the input -> resources -> output flow of Modules less explicit, and explicitness is a core design goal.
I know, we have to repeat a lot of variables between different modules
I try to do this
Define a the set of common variables e.g. common_tags at the bottom/top of the variables.tf file for all modules. Usually, your tech ops admin/cloud admin will have a template project created for this.
For each module, I add the following as the last item
global_var = var.global_var_val
An example is common tags. In any root/child module I combine them using merge() function. I hope that makes sense.
You can use -var-file to pass the overrides. Example:
terraform -chdir=staging/000base apply -var-file ../../global.tfvars
Other way can be dedicated shared module.
For example you have module with:
output "my_var" {
value = "apollo440"
}
And in other modules you can use it like:
module "gvars" {
# source = "git#github.com:user/terraform-global-vars.git?ref=v0.0.1-alpha"
source="../../../modules/global_vars"
}
provider "something" {
name="${module.gvars.my_var}"
}
Third way could be to use https://registry.terraform.io/providers/hashicorp/http/latest/docs/data-sources/http to query some http endpoint.
Ouh... and forth way could be to utilize Vault Provider https://registry.terraform.io/providers/hashicorp/vault/latest/docs
For pathing constants between lots of modules we can use the following simple way.
/modules/global_constants/outputs.tf:
Describe module with global constants as outputs:
output "parameter_1" {
value = "value_1"
sensitive = true
}
output "parameter_2" {
value = "value_2"
sensitive = true
}
/example_1.tf
After we can use in any *.tf
module "global_settings" {
source = "./modules/global_constants"
}
data "azurerm_key_vault" "keyvault" {
name = module.global_settings.parameter_1
resource_group_name = module.global_settings.parameter_2
}
/modules/module2/main.tf
Or in other any modules:
module "global_settings" {
source = "../global_constants"
}
data "azurerm_key_vault" "keyvault" {
name = module.global_settings.parameter_1
resource_group_name = module.global_settings.parameter_2
}
I am using terraform 0.12.8 and I am trying to write a resource which would iterate over the following variable structure:
variable "applications" {
type = map(string)
default = {
"app1" = "test,dev,prod"
"app2" = "dev,prod"
}
}
My resource:
resource "aws_iam_user" "custom" {
for_each = var.applications
name = "circleci-${var.tags["ServiceType"]}-user-${var.tags["Environment"]}-${each.key}"
path = "/"
}
So, I can iterate over my map. However, I can't figure out how to verify that var.tags["Environment"] is enabled for specific app e.g. app1.
Basically, I want to ensure that the resource is created for each application as long as the Environment variable is in the list referencing app name in the applications map.
Could someone help me out here?
Please note that I am happy to go with a different variable structure if you have something to propose that would accomplish my goal.
I am learning terraform modules.
I've created module for Google Provider.
provider "google" {
credentials = "${var.credentials}"
project = "${var.project_id}"
region = "${var.region}"
zone = "${var.zone}"
}
I want to pass credential file path form the module consuming above.
Here is the consumer module.
main.tf
module "google" {
source = "../modules/google-provider"
project_id = "${var.project_id}"
credentials = "${var.credentials}"
}
variables.tf
variable "credentials" {
default = "${file("cred.json")}"
}
This is the error I am getting:
Error: variable "credentials": default may not contain interpolations
I read this stackoverflow comment but did not understand how it will work.
Thank you for the help in advance.
from the docs,
When you declare variables in the root module of your configuration,
you can set their values using CLI options and environment variables.
When you declare them in child modules, the calling module should pass
values in the module block.
In your case,
#This is your calling module, hence you need to pass variables to child module from here
module "google" {
source = "../modules/google-provider"
passed_project_id_to_child = "${var.project_id}"
passed_credentials_to_child = "${var.credentials}"
}
UPDATE: for some reasons, terraform is not allowing you to read file with interpolation syntax create a data source of type local_file docs
data "local_file" "credJSON" {
filename = "./cred.json"
}
then you will need to do something like this in your module's configuration file or you can also create a seperate file for that too,
variable passed_project_id_to_child{
default = "${jsonencode(data.credJSON.content).projectId}"
}
variable passed_credentials_to_child{}
provider "google" {
credentials = "${var.passed_project_id_to_child}"
project = "${var.passed_project_id_to_child}"
region = "${var.region}"
zone = "${var.zone}"
}
Hopefully this works.
Read more here