6bed3008a5
It's been a long time since we gave this page an overhaul, and with our ongoing efforts to make plan and apply incorporate all of the side-effects that might need to be done against a configuration it seems like a good time for some restructuring in that vein. The starting idea here is to formally split the many "terraform plan" options into a few different categories: - Planning modes - Planning options - Other options The planning modes and options are the subset that are also accepted by "terraform apply" when it's running in its default mode of generating a plan and then prompting for interactive approval of it. This then allows us to avoid duplicating all of that information on the "terraform apply" page, and thus allows us to spend more words discussing each of them. This set of docs is intended as a fresh start into which we'll be able to more surgically add in the information about -refresh-only and -replace=... once we have those implemented. Consequently there are some parts of this which may seem a little overwraught for what it's currently describing; that's a result of my having prepared this by just deleting the -refresh-only and -replace=... content from our initial docs draft and submitted the result, in anticipation of re-adding the parts I've deleted here in the very near future in other commits.
3.9 KiB
| layout | page_title | sidebar_current | description |
|---|---|---|---|
| docs | Internals: Resource Address | docs-internals-resource-addressing | A resource address is a string that identifies zero or more resource instances in your overall configuration. |
Resource Addressing
A resource address is a string that identifies zero or more resource instances in your overall configuration.
An address is made up of two parts:
[module path][resource spec]
In some contexts Terraform might allow for an incomplete resource address that only refers to a module as a whole, or that omits the index for a multi-instance resource. In those cases, the meaning depends on the context, so you'll need to refer to the documentation for the specific feature you are using which parses resource addresses.
Module path
A module path addresses a module within the tree of modules. It takes the form:
module.module_name[module index]
module- Module keyword indicating a child module (non-root). Multiplemodulekeywords in a path indicate nesting.module_name- User-defined name of the module.[module index]- (Optional) Index to select an instance from a module call that has multiple instances, surrounded by square bracket characters ([and]).
An address without a resource spec, i.e. module.foo applies to every resource within
the module if a single module, or all instances of a module if a module has multiple instances.
To address all resources of a particular module instance, include the module index in the address,
such as module.foo[0].
If the module path is omitted, the address applies to the root module.
An example of the module keyword delineating between two modules that have multiple instances:
module.foo[0].module.bar["a"]
-> Module index only applies to modules in Terraform v0.13 or later. In earlier versions of Terraform, a module could not have multiple instances.
Resource spec
A resource spec addresses a specific resource instance in the selected module. It has the following syntax:
resource_type.resource_name[instance index]
resource_type- Type of the resource being addressed.resource_name- User-defined name of the resource.[instance index]- (Optional) Index to select an instance from a resource that has multiple instances, surrounded by square bracket characters ([and]).
-> In Terraform v0.12 and later, a resource spec without a module path prefix matches only resources in the root module. In earlier versions, a resource spec without a module path prefix would match resources with the same type and name in any descendent module.
Index values for Modules and Resources
The following specifications apply to index values on modules and resources with multiple instances:
[N]whereNis a0-based numerical index into a resource with multiple instances specified by thecountmeta-argument. Omitting an index when addressing a resource wherecount > 1means that the address references all instances.["INDEX"]whereINDEXis a alphanumerical key index into a resource with multiple instances specified by thefor_eachmeta-argument.
Examples
count Example
Given a Terraform config that includes:
resource "aws_instance" "web" {
# ...
count = 4
}
An address like this:
aws_instance.web[3]
Refers to only the last instance in the config, and an address like this:
aws_instance.web
Refers to all four "web" instances.
for_each Example
Given a Terraform config that includes:
resource "aws_instance" "web" {
# ...
for_each = {
"terraform": "value1",
"resource": "value2",
"indexing": "value3",
"example": "value4",
}
}
An address like this:
aws_instance.web["example"]
Refers to only the "example" instance in the config.