72 lines
2.9 KiB
Markdown
72 lines
2.9 KiB
Markdown
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---
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layout: "docs"
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page_title: "Provider Metadata"
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sidebar_current: "docs-internals-provider-meta"
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description: |-
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For advanced use cases, modules can provide some pre-defined metadata for providers.
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---
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# Provider Metadata
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In some situations it's beneficial for a provider to offer an interface
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through which modules can pass it information unrelated to the resources
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in the module, but scoped on a per-module basis. The provider metadata
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functionality allows a provider to do this in a straightforward way.
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~> **Advanced Topic!** This page covers technical details
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of Terraform. You don't need to understand these details to
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effectively use Terraform. The details are documented here for
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module authors and provider developers working on advanced
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functionality.
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~> **Experimental Feature!** This functionality is still considered
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experimental, and anyone taking advantage of it should [coordinate
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with the Terraform team](https://github.com/hashicorp/terraform/issues/new)
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to help the team understand how the feature is being used and to make
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sure their use case is taken into account as the feature develops.
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## Defining the Schema
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Before a provider can receive information from a module, the provider
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must strictly define the data it can accept. You can do this by setting
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the `ProviderMeta` property on your `schema.Provider` struct. Its value
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functions similarly to the provider config: a map of strings to the
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`schema.Schema` describing the values those strings accept.
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## Using the Data
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When Terraform calls your provider, you can use the `schema.ResourceData`
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that your `Create`, `Read`, and `Update` functions already use to get
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access to the provider metadata being passed. First define a struct
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that matches your schema, then call the `GetProviderSchema` method on
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your `schema.ResourceData`, passing a pointer to a variable of that type.
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The variable will be populated with the provider metadata, and will return
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an error if there was an issue with parsing the data into the struct.
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## Specifying Data in Modules
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To include data in your modules, create a `provider_meta` nested block under
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your module's `terraform` block, with the name of the provider it's trying
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to pass information to:
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```hcl
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terraform {
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provider_meta "my-provider" {
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hello = "world"
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}
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}
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```
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The `provider_meta` block must match the schema the provider has defined.
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## Versioning Your Modules
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Any module taking advantage of this functionality must make sure that the
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provider metadata supplied matches the schema defined in the provider, and
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that the version of Terraform that is being run has support for the provider
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metadata functionality. It's therefore recommended that any module taking
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advantage of this functionality should specify a minimum Terraform version of
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0.13.0 or higher, and a minimum version of each of the providers it specifies
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metadata as the first version the schema being used was supported by the
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provider.
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