» CLI Configuration File (.terraformrc or terraform.rc)

The CLI configuration file configures per-user settings for CLI behaviors, which apply across all Terraform working directories. This is separate from your infrastructure configuration.

» Location

The configuration is placed in a single file whose location depends on the host operating system:

  • On Windows, the file must be named named terraform.rc and placed in the relevant user's %APPDATA% directory. The physical location of this directory depends on your Windows version and system configuration; use $env:APPDATA in PowerShell to find its location on your system.
  • On all other systems, the file must be named .terraformrc (note the leading period) and placed directly in the home directory of the relevant user.

On Windows, beware of Windows Explorer's default behavior of hiding filename extensions. Terraform will not recognize a file named terraform.rc.txt as a CLI configuration file, even though Windows Explorer may display its name as just terraform.rc. Use dir from PowerShell or Command Prompt to confirm the filename.

The location of the Terraform CLI configuration file can also be specified using the TF_CLI_CONFIG_FILE environment variable.

» Configuration File Syntax

The configuration file uses the same HCL syntax as .tf files, but with different attributes and blocks. The following example illustrates the general syntax; see the following section for information on the meaning of each of these settings:

plugin_cache_dir   = "$HOME/.terraform.d/plugin-cache"
disable_checkpoint = true

» Available Settings

The following settings can be set in the CLI configuration file:

» Credentials

Terraform Cloud provides a number of remote network services for use with Terraform, and Terraform Enterprise allows hosting those services inside your own infrastructure. For example, these systems offer both remote operations and a private module registry.

When interacting with Terraform-specific network services, Terraform expects to find API tokens in CLI configuration files in credentials blocks:

credentials "app.terraform.io" {
  token = "xxxxxx.atlasv1.zzzzzzzzzzzzz"
}

If you are running the Terraform CLI interactively on a computer with a web browser, you can use the terraform login command to get credentials and automatically save them in the CLI configuration. If not, you can manually write credentials blocks.

You can have multiple credentials blocks if you regularly use services from multiple hosts. Many users will configure only one, for either Terraform Cloud (at app.terraform.io) or for their organization's own Terraform Enterprise host. Each credentials block contains a token argument giving the API token to use for that host.

» Credentials Helpers

If you would prefer not to store your API tokens directly in the CLI configuration as described in the previous section, you can optionally instruct Terraform to use a different credentials storage mechanism by configuring a special kind of plugin program called a credentials helper.

credentials_helper "example" {
  args = []
}

credentials_helper is a configuration block that can appear at most once in the CLI configuration. Its label ("example" above) is the name of the credentials helper to use. The args argument is optional and allows passing additional arguments to the helper program, for example if it needs to be configured with the address of a remote host to access for credentials.

A configured credentials helper will be consulted only to retrieve credentials for hosts that are not explicitly configured in a credentials block as described in the previous section. Conversely, this means you can override the credentials returned by the helper for a specific hostname by writing a credentials block alongside the credentials_helper block.

Terraform does not include any credentials helpers in the main distribution. To learn how to write and install your own credentials helpers to integrate with existing in-house credentials management systems, see the guide to Credentials Helper internals.

» Provider Installation

The default way to install provider plugins is from a provider registry. The origin registry for a provider is encoded in the provider's source address, like registry.terraform.io/hashicorp/aws. For convenience in the common case, Terraform allows omitting the hostname portion for providers on registry.terraform.io, so you can write shorter public provider addresses like hashicorp/aws.

Downloading a plugin directly from its origin registry is not always appropriate, though. For example, the system where you are running Terraform may not be able to access an origin registry due to firewall restrictions within your organization or your locality.

To allow using Terraform providers in these situations, there are some alternative options for making provider plugins available to Terraform which we'll describe in the following sections.

» Explicit Installation Method Configuration

A provider_installation block in the CLI configuration allows overriding Terraform's default installation behaviors, so you can force Terraform to use a local mirror for some or all of the providers you intend to use.

The general structure of a provider_installation block is as follows:

provider_installation {
  filesystem_mirror {
    path    = "/usr/share/terraform/providers"
    include = ["example.com/*/*"]
  }
  direct {
    exclude = ["example.com/*/*"]
  }
}

Each of the nested blocks inside the provider_installation block specifies one installation method. Each installation method can take both include and exclude patterns that specify which providers a particular installation method can be used for. In the example above, we specify that any provider whose origin registry is at example.com can be installed only from the filesystem mirror at /usr/share/terraform/providers, while all other providers can be installed only directly from their origin registries.

If you set both both include and exclude for a particular installation method, the exclusion patterns take priority. For example, including registry.terraform.io/hashicorp/* but also excluding registry.terraform.io/hashicorp/dns will make that installation method apply to everything in the hashicorp namespace with the exception of hashicorp/dns.

As with provider source addresses in the main configuration, you can omit the registry.terraform.io/ prefix for providers distributed through the public Terraform registry, even when using wildcards. For example, registry.terraform.io/hashicorp/* and hashicorp/* are equivalent. */* is a shorthand for registry.terraform.io/*/*, not for */*/*.

The following are the two supported installation method types:

  • direct: request information about the provider directly from its origin registry and download over the network from the location that registry indicates. This method expects no additional arguments.

  • filesystem_mirror: consult a directory on the local disk for copies of providers. This method requires the additional argument path to indicate which directory to look in.

    Terraform expects the given directory to contain a nested directory structure where the path segments together provide metadata about the available providers. The following two directory structures are supported:

    • Packed layout: HOSTNAME/NAMESPACE/TYPE/terraform-provider-TYPE_VERSION_TARGET.zip is the distribution zip file obtained from the provider's origin registry.
    • Unpacked layout: HOSTNAME/NAMESPACE/TYPE/VERSION/TARGET is a directory containing the result of extracting the provider's distribution zip file.

    In both layouts, the VERSION is a string like 2.0.0 and the TARGET specifies a particular target platform using a format like darwin_amd64, linux_arm, windows_amd64, etc.

    If you use the unpacked layout, Terraform will attempt to create a symbolic link to the mirror directory when installing the provider, rather than creating a deep copy of the directory. The packed layout prevents this because Terraform must extract the zip file during installation.

    You can include multiple filesystem_mirror blocks in order to specify several different directories to search.

  • network_mirror: consult a particular HTTPS server for copies of providers, regardless of which registry host they belong to. This method requires the additional argument url to indicate the mirror base URL, which should use the https: scheme and end with a trailing slash.

    Terraform expects the given URL to be a base URL for an implementation of the provider network mirror protocol, which is designed to be relatively easy to implement using typical static website hosting mechanisms.

Terraform will try all of the specified methods whose include and exclude patterns match a given provider, and select the newest version available across all of those methods that matches the version constraint given in each Terraform configuration. If you have a local mirror of a particular provider and intend Terraform to use that local mirror exclusively, you must either remove the direct installation method altogether or use its exclude argument to disable its use for specific providers.

» Implied Local Mirror Directories

If your CLI configuration does not include a provider_installation block at all, Terraform produces an implied configuration. The implied configuration includes a selection of filesystem_mirror methods and then the direct method.

The set of directories Terraform can select as filesystem mirrors depends on the operating system where you are running Terraform:

  • Windows: %APPDATA%/HashiCorp/Terraform/plugins
  • Mac OS X: ~/Library/Application Support/io.terraform/plugins and /Library/Application Support/io.terraform/plugins
  • Linux and other Unix-like systems: Terraform implements the XDG Base Directory specification and appends terraform/plugins to all of the specified data directories. Without any XDG environment variables set, Terraform will use ~/.local/share/terraform/plugins, /usr/local/share/terraform/plugins, and /usr/share/terraform/plugins.

Terraform will create an implied filesystem_mirror method block for each of the directories indicated above that exists when Terraform starts up.

In addition to the zero or more implied filesystem_mirror blocks, Terraform also creates an implied direct block. Terraform will scan all of the filesystem mirror directories to see which providers are placed there and automatically exclude all of those providers from the implied direct block. (This automatic exclude behavior applies only to implicit direct blocks; if you use explicit provider_installation you will need to write the intended exclusions out yourself.)

» Provider Plugin Cache

By default, terraform init downloads plugins into a subdirectory of the working directory so that each working directory is self-contained. As a consequence, if you have multiple configurations that use the same provider then a separate copy of its plugin will be downloaded for each configuration.

Given that provider plugins can be quite large (on the order of hundreds of megabytes), this default behavior can be inconvenient for those with slow or metered Internet connections. Therefore Terraform optionally allows the use of a local directory as a shared plugin cache, which then allows each distinct plugin binary to be downloaded only once.

To enable the plugin cache, use the plugin_cache_dir setting in the CLI configuration file. For example:

plugin_cache_dir = "$HOME/.terraform.d/plugin-cache"

This directory must already exist before Terraform will cache plugins; Terraform will not create the directory itself.

Please note that on Windows it is necessary to use forward slash separators (/) rather than the conventional backslash (\) since the configuration file parser considers a backslash to begin an escape sequence.

Setting this in the configuration file is the recommended approach for a persistent setting. Alternatively, the TF_PLUGIN_CACHE_DIR environment variable can be used to enable caching or to override an existing cache directory within a particular shell session:

export TF_PLUGIN_CACHE_DIR="$HOME/.terraform.d/plugin-cache"

When a plugin cache directory is enabled, the terraform init command will still use the configured or implied installation methods to obtain metadata about which plugins are available, but once a suitable version has been selected it will first check to see if the chosen plugin is already available in the cache directory. If so, Terraform will use the previously-downloaded copy.

If the selected plugin is not already in the cache, Terraform will download it into the cache first and then copy it from there into the correct location under your current working directory. When possible Terraform will use symbolic links to avoid storing a separate copy of a cached plugin in multiple directories.

The plugin cache directory must not also be one of the configured or implied filesystem mirror directories, since the cache management logic conflicts with the filesystem mirror logic when operating on the same directory.

Terraform will never itself delete a plugin from the plugin cache once it has been placed there. Over time, as plugins are upgraded, the cache directory may grow to contain several unused versions which you must delete manually.

» Removed Settings

The following settings are supported in Terraform 0.12 and earlier but are no longer recommended for use:

  • providers - a configuration block that allows specifying the locations of specific plugins for each named provider. This mechanism is deprecated because it is unable to specify a version number and source for each provider. See Provider Installation above for the replacement of this setting in Terraform 0.13 and later.