71 lines
1.6 KiB
Markdown
71 lines
1.6 KiB
Markdown
---
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layout: "docs"
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page_title: "Internals: Resource Address"
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sidebar_current: "docs-internals-resource-addressing"
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description: |-
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Resource addressing is used to target specific resources in a larger
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infrastructure.
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---
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# Resource Addressing
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A __Resource Address__ is a string that references a specific resource in a
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larger infrastructure. An address is made up of two parts:
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```
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[module path][resource spec]
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```
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__Module path__:
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A module path addresses a module within the tree of modules. It takes the form:
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```
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module.A.module.B.module.C...
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```
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Multiple modules in a path indicate nesting. If a module path is specified
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without a resource spec, the address applies to every resource within the
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module. If the module path is omitted, this addresses the root module.
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__Resource spec__:
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A resource spec addresses a specific resource in the config. It takes the form:
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```
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resource_type.resource_name[N]
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```
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* `resource_type` - Type of the resource being addressed.
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* `resource_name` - User-defined name of the resource.
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* `[N]` - where `N` is a `0`-based index into a resource with multiple
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instances specified by the `count` meta-parameter. Omitting an index when
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addressing a resource where `count > 1` means that the address references
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all instances.
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## Examples
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Given a Terraform config that includes:
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```hcl
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resource "aws_instance" "web" {
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# ...
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count = 4
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}
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```
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An address like this:
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```
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aws_instance.web[3]
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```
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Refers to only the last instance in the config, and an address like this:
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```
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aws_instance.web
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```
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Refers to all four "web" instances.
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