So i want to get the variable in the terraform remote state, however we have a number of different one per environment on the shared route53
So for a given environement, we want to pull the zone id out as such;
zone_id = data.terraform_remote_state.route_53.route53_zone_${var.environment}_id
How would I do this please.
In general, it is not possible to use arbitrary dynamic strings as variable names.
However, in this particular case the outputs from terraform_remote_state are collection values and so you can use the index syntax to access a dynamically-built key from your map value:
data.terraform_remote_state.outputs.route53["route53_zone_${var.environment}_id"]
With that said, if possible I would recommend structuring the output values better so that the Route53 zone ids are given as a map by environment, so that this can be obtained in a more intuitive way.
For example, you could make your route53 output be a map of objects whose keys are the environment names:
data.terraform_remote_state.outputs.route53[var.environment].zone_id
output "route53" {
value = tomap({
production = {
zone_id = aws_route53_zone.production.id
}
staging = {
zone_id = aws_route53_zone.staging.id
}
})
}
Or, if you have a variety of different per-environment settings you could structure it as a single output value that is a map of all of those per environment settings keyed by environment name:
data.terraform_remote_state.outputs.environments[var.environment].route53_zone_id
output "environments" {
value = tomap({
production = {
ec2_vpc_id = aws_vpc.production.id
route53_zone_id = aws_route53_zone.production.id
}
staging = {
ec2_vpc_id = aws_vpc.staging.id
route53_zone_id = aws_route53_zone.staging.id
}
})
}
This doesn't change anything about the ultimate result, but grouping things by your environment keys in your outputs is likely to make your intent clearer to future maintainers of these configurations.
(You might also consider whether it'd be better to have a separate configuration/state per environment rather than managing them altogether, but that is a big topic in itself.)
Related
I have a map with some environment ID's as the key, then keywords as the values in a list.
variable "environments" {
type = map(list(string))
default = {
"env-one" = ["dev", "test", "stage", "staging"],
"env-two" = ["prod", "production", "live"]
}
}
I'm looking to use this to set the environment name based on the value of var.context["stage"].
So, if var.context["stage"] is equal to staging the value of environment will be dev
I was initially thinking to use lookup(), something like;
environment = "${lookup(var.environments, var.context["stage"])}"
However, I realise that's looking up the wrong way (finding the value as opposed to the key), and also it won't work as part of a map. So presumably I need to look through the map and run the lookup (albeit) backwards(?) on each iteration?
You would want to restructure the type into map(string). Then it would follow that the value would be:
{
"dev" = "env-one",
"test" = "env-one",
"stage" = "env-one",
"staging" = "env-one",
"prod" = "env-two",
"production" = "env-two",
"live" = "env-two"
}
You could also modify this to be map(object) to contain more information. Based on the usage described in the question, this would actually make more sense to be a local. If you were to place this data into a locals block named environments, then the key-value pair could be accessed (according to the question) like local.environments[var.context["stage"]].
I am trying to create a map of secondary ranges for the GCP VPC module here and have the following defined in my locals:
secondary_ranges = {
for name, config in var.subnet_config : config.subnet_name => [
{
range_name = local.ip_range_pods
ip_cidr_range = "10.${index(keys(var.subnet_config), name)}.0.0/17"
},
{
range_name = local.ip_range_services
ip_cidr_range = "10.${index(keys(var.subnet_config), name)}.128.0/17"
}
]
}
subnet_config is defined as follows:
subnet_config = {
cluster1 = {
region = "us-east1"
subnet_name = "default"
},
cluster2 = {
region = "us-west1"
subnet_name = "default"
}
}
This creates the secondary subnets just fine if the subnet names are unique but fails with the error below if the subnet names (which end up being the key values) are not unique:
Two different items produced the key "default" in this 'for' expression. If duplicates are expected, use the ellipsis (...) after the value expression to enable grouping by key.
I'm trying to figure out if I can use grouping mode if the value is a list and if so, how?
Any help would be greatly appreciated.
If you use the grouping mode in this case then it would be to group the outermost for expression, which is producing a map, because that's the one whose keys you'd be grouping by.
We can start by adding the grouping mode modifier to that and see what happens:
secondary_ranges_pairs = {
for name, config in var.subnet_config : config.subnet_name => [
{
range_name = local.ip_range_pods
ip_cidr_range = "10.${index(keys(var.subnet_config), name)}.0.0/17"
},
{
range_name = local.ip_range_services
ip_cidr_range = "10.${index(keys(var.subnet_config), name)}.128.0/17"
}
]...
}
The effect of the expression above would be to create a map of lists of lists of objects, where the deepest lists are each pairs of objects because of how your inner for expression is written.
To turn that into the map of lists of objects which I think you're hoping for, you can then use flatten in a separate step:
secondary_ranges = {
for k, pairs in local.secondary_ranges_pairs : k => flatten(pairs)
}
flatten recursively walks a data structure where there are lists of lists and concatenates all of the nested lists together into a single flat list.
A word of caution: you seem to be using a lexical sort of the subnet_config keys in order to derive network numbering. That means that if you add new elements to your var.subnet_config whose keys sort earlier than any existing ones (for example, if you were to add in a cluster0 into what you showed in your question) then you'll implicitly renumber all of the subsequent networks, which is likely to cause a lot of churn recreating objects, and the change might not even be possible if those networks contain other objects.
I'd typically recommend instead being explicit about what number you've assigned to each network, by including then as part of the var.subnet_config objects. You can then clearly see which numbers you've assigned and make sure that any new networks will always be assigned a later number without disturbing any existing assignments.
There's also an official Terraform module hashicorp/subnets/cidr which aims to encapsulate subnet numbering calculations. The design of that module means that it wouldn't be completely straightforward to adopt it for your use-case (since you're allocating two levels of subnet at once) but it might be useful to study to see whether any of the design tradeoffs made there are relevant to your module.
I'm trying to create configurations in terraform that I can later pass to modules (I'm doing this to work around the lack of "count" in modules).
The closest thing I got was using a null_data_source but the problem with that is that it only supports a single level of properties in inputs:
data "null_data_source" "my_data" {
count = var.my_data_count
inputs = {
settings = { ... } //this doesn't work
}
}
Then I looked at the docs of how to create a custom provider but couldn't work around the types that terraform supports - TypeMap will automatically turned into map[string]string unless I pass in the Elem property but that also only accepts terraform defined types (it doesn't accept standard golang types e.g.: map[string]interface{} or interface{}).
Does anyone know a way to get unstructured data as config like this?
There is no such thing as "unstructured data" in Terraform: every value has an associated type. However, in Terraform 0.12 introduced two structural types that allow for different element/attribute types to be mixed together inside a single value, which is not possible for the collection types.
You can use Local Values if you need to factor out the expressions for these structural values for use in multiple locations:
locals {
your_data = {
settings = {
foo = "bar"
baz = []
}
}
}
Although the details of this often don't matter, Terraform will see the above as being of the following type:
object({
settings = object({
foo = string
baz = tuple([])
})
})
As the author of a module, you can associated with each variable a type constraint that can both check that the given value has the appropriate type and give Terraform some hints to interpret such a value differently. For example, if baz in the above example were a list of strings whose length isn't fixed by the module (often the case) then you can specify it as such in your type constraint:
variable "example" {
type = object({
settings = object({
foo = string
baz = list(string)
})
})
}
Then the caller can pass in the local value we constructed earlier:
module "example" {
source = "./modules/example"
example = local.your_data
}
Terraform will then take the tuple([]) value from the local value and convert it automatically to list(string), in this case creating an empty list of strings.
For Terraform 0.11 your options are more limited, because it does not have structural types. In that case, the usual approach is to flatten the structure into many separate variables and set them separately, but then it's not possible to conveniently construct them all in one place and pass them as a single value.
I am creating a series of resources in terraform (in this case, dynamo DB table). I want to apply IAM policies to subgroups of them. E.g.
resource "aws_dynamodb_table" "foo" {
count = "${length(var.tables)}"
name = "foo-${element(var.tables,count.index)}"
tags {
Name = "foo-${element(var.tables,count.index)}"
Environment = "<unsure how to get this>"
Source = "<unsure how to get this>"
}
}
All of these share some common element, e.g. var.sources is a list composed of the Cartesian product of var.environments and var.sources:
environments = ["dev","qa","prod"]
sources = ["a","b","c"]
So:
tables = ["a:dev","a:qa","a:prod","b:dev","b:qa","b:prod","c:dev","c:qa","c:prod"]
I want to get the arns of the created dynamo tables that have, e.g. c (i.e. those with the name ["c:dev","c:qa","c:prod"]) or prod(i.e. those with the name ["a:prod","b:prod","c:prod"]).
Is there any sane way to do this with terraform 0.11 (or even 0.12 for that matter)?
I am looking to:
group the dynamo db table resources by some of the inputs (environment or source) so I can apply some policy to each group
Extract the input for each created one so I can apply the correct tags
I was thinking of, potentially, instead of creating the cross-product list, to create maps for each input:
{
"a": ["dev","qa","prod"],
"b": ["dev","qa","prod"],
"c": ["dev","qa","prod"]
}
or
{
"dev": ["a","b","c"],
"qa": ["a","b","c"],
"prod": ["a","b","c"]
}
It would make it easy to find the target names for each one, since I can look up by the input, but that only gives me the names, but not make it easy to get the actual resources (and hence the arns).
Thanks!
A Terraform 0.12 solution would be to derive the cartesian product automatically (using setproduct) and use a for expression to shape it into a form that's convenient for what you need. For example:
locals {
environments = ["dev", "qa", "prod"]
sources = ["a", "b", "c"]
tables = [for pair in setproduct(local.environments, local.sources) : {
environment = pair[0]
source = pair[1]
name = "${pair[1]}:${pair[0]}"
})
}
resource "aws_dynamodb_table" "foo" {
count = length(local.tables)
name = "foo-${local.tables[count.index].name}"
tags {
Name = "foo-${local.tables[count.index].name}"
Environment = local.tables[count.index].environment
Source = local.tables[count.index].source
}
}
At the time I write this the resource for_each feature is still in development, but in a near-future Terraform v0.12 minor release it should be possible to improve this further by making these table instances each be identified by their names, rather than by their positions in the local.tables list:
# (with the same "locals" block as in the above example)
resource "aws_dynamodb_table" "foo" {
for_each = { for t in local.tables : t.name => t }
name = "foo-${each.key}"
tags {
Name = "foo-${each.key}"
Environment = each.value.environment
Source = each.value.source
}
}
As well as cleaning up some redundancy in the syntax, this new for_each form will cause Terraform to identify this instances with addresses like aws_dynamodb_table.foo["a:dev"] instead of aws_dynamodb_table.foo[0], which means that you'll be able to freely add and remove members of the two initial lists without causing churn and replacement of other instances because the list indices changed.
This sort of thing would be much harder to achieve in Terraform 0.11. There are some general patterns that can help translate certain 0.12-only constructs to 0.11-compatible features, which might work here:
A for expression returning a sequence (one with square brackets around it, rather than braces) can be simulated with a data "null_data_source" block with count set, if the result would've been a map of string values only.
A Terraform 0.12 object in a named local value can in principle be replaced with a separate simple map of local value for each object attribute, using a common set of keys in each map.
Terraform 0.11 does not have the setproduct function, but for sequences this small it's not a huge problem to just write out the cartesian product yourself as you did in the question here.
The result will certainly be very inelegant, but I expect it's possible to get something working on Terraform 0.11 if you apply the above ideas and make some compromises.
I need to create 6 subnets with below cidr value but it's order has been changed while creating it with terraform.
private_subnets = {
"10.1.80.0/27" = "x"
"10.1.80.32/27" = "x"
"10.1.80.64/28" = "y"
"10.1.80.80/28" = "y"
"10.1.80.96/27" = "z"
"10.1.80.128/27" = "z"
}
Terraform is creating with 10.1.80.0/27 , 10.1.80.128/27,10.1.80.32/27,10.1.80.64/28,10.1.80.80/28,10.1.80.96/27 order
Module of terraform:
resource "aws_subnet" "private" {
vpc_id = "${var.vpc_id}"
cidr_block = "${element(keys(var.private_subnets), count.index)}"
availability_zone = "${element(var.availability_zones, count.index)}"
count = "${length(var.private_subnets)}"
tags {
Name = "${lookup(var.private_subnets, element(keys(var.private_subnets), count.index))}
}
}
Updated Answer:
Thanks to the discussion in the comments, I revise my answer:
You are assuming an order within a dictionary. This is not intended behaviour. As from your example, one can see that terraform orders the keys alphabetically internally, i.e., you can "think" of your variable as
private_subnets = {
"10.1.80.0/27" = "x"
"10.1.80.128/27" = "z"
"10.1.80.32/27" = "x"
"10.1.80.64/28" = "y"
"10.1.80.80/28" = "y"
"10.1.80.96/27" = "z"
}
You are running into problems, because you are having mismatches with your other variable var.availability_zones where you assume the index to be sorted the same as for var.private_subnets.
Relying on the above ordering (alphabetically), is not a good solution, since it may change with any version of terraform (order of keys is not guaranteed).
Hence, I propose to use a list of maps:
private_subnets = [
{
"cidr" = "10.1.80.0/27"
"name" = "x"
"availability_zone" = 1
},
{
"cidr" = "10.1.80.32/27"
"name" = "x"
"availability_zone" = 2
},
…
]
I encoded the availability zone as index of your var.availability_zones list. However, you could also consider using the availability zone directly.
The adaption of your code is straightforward: Get (element(…)) the list element to get the map and then lookup(…) the desired key.
Old Answer (not applicable here):
Before Terraform creates any resources, it creates a graphstructure to represent all the objects it wants to track (create, update, delete) and the dependencies upon one another.
In your example, 6 different aws_subnet objects are created in the graph which do not depend on each other (there is no variable in one subnet dependent on another subnet).
When Terraform now tries to create the attributes, it does so concurrently in (potentially) multiple threads and creates resources potentially simultaniously, if they do not depend on each other.
This is why you might see very different orders of execution within multiple runs of terraform.
Note that this is a feature, since if you have many resources to be created that have no dependency on each other, they all are created simultaneously saving a lot of time with long-running creation operations.
A solution to your problem is to explicitly model the dependencies you are thinking of. Why should one subnet be created before the other? And if so, how can you make them dependent (e.g. via depends_on parameter)?
Answering this questions should bring you into the right direction to model your code according to your required layout.