Environment Variables
Terraform refers to a number of environment variables to customize various aspects of its behavior. None of these environment variables are required when using Terraform, but they can be used to change some of Terraform's default behaviors in unusual situations, or to increase output verbosity for debugging.
TF_LOG
Enables detailed logs to appear on stderr which is useful for debugging. For example:
To disable, either unset it, or set it to off. For example:
For more on debugging Terraform, check out the section on Debugging.
TF_LOG_PATH
This specifies where the log should persist its output to. Note that even when TF_LOG_PATH is set, TF_LOG must be set in order for any logging to be enabled. For example, to always write the log to the directory you're currently running terraform from:
For more on debugging Terraform, check out the section on Debugging.
TF_INPUT
If set to "false" or "0", causes terraform commands to behave as if the -input=false flag was specified. This is used when you want to disable prompts for variables that haven't had their values specified. For example:
TF_VAR_name
Environment variables can be used to set variables. The environment variables must be in the format TF_VAR_name and this will be checked last for a value. For example:
For more on how to use TF_VAR_name in context, check out the section on Variable Configuration.
TF_CLI_ARGS and TF_CLI_ARGS_name
The value of TF_CLI_ARGS will specify additional arguments to the
command-line. This allows easier automation in CI environments as well as
modifying default behavior of Terraform on your own system.
These arguments are inserted directly after the subcommand
(such as plan) and before any flags specified directly on the command-line.
This behavior ensures that flags on the command-line take precedence over
environment variables.
For example, the following command: TF_CLI_ARGS="-input=false" terraform apply -force
is the equivalent to manually typing: terraform apply -input=false -force.
The flag TF_CLI_ARGS affects all Terraform commands. If you specify a
named command in the form of TF_CLI_ARGS_name then it will only affect
that command. As an example, to specify that only plans never refresh,
you can set TF_CLI_ARGS_plan="-refresh=false".
The value of the flag is parsed as if you typed it directly to the shell. Double and single quotes are allowed to capture strings and arguments will be separated by spaces otherwise.
TF_DATA_DIR
TF_DATA_DIR changes the location where Terraform keeps its
per-working-directory data, such as the current backend configuration.
By default this data is written into a .terraform subdirectory of the
current directory, but the path given in TF_DATA_DIR will be used instead
if non-empty.
In most cases it should not be necessary to set this variable, but it may be useful to do so if e.g. the working directory is not writable.
The data directory is used to retain data that must persist from one command
to the next, so it's important to have this variable set consistently throughout
all of the Terraform workflow commands (starting with terraform init) or else
Terraform may be unable to find providers, modules, and other artifacts.
TF_WORKSPACE
For multi-environment deployment, in order to select a workspace, instead of doing terraform workspace select your_workspace, it is possible to use this environment variable. Using TF_WORKSPACE allow and override workspace selection.
For example:
Using this environment variable is recommended only for non-interactive usage, since in a local shell environment it can be easy to forget the variable is set and apply changes to the wrong state.
For more information regarding workspaces, check out the section on Using Workspaces.
TF_IN_AUTOMATION
If TF_IN_AUTOMATION is set to any non-empty value, Terraform adjusts its
output to avoid suggesting specific commands to run next. This can make the
output more consistent and less confusing in workflows where users don't
directly execute Terraform commands, like in CI systems or other wrapping
applications.
This is a purely cosmetic change to Terraform's human-readable output, and the exact output differences can change between minor Terraform versions.
For more details, see Running Terraform in Automation.
TF_REGISTRY_DISCOVERY_RETRY
Set TF_REGISTRY_DISCOVERY_RETRY to configure the max number of request retries
the remote registry client will attempt for client connection errors or
500-range responses that are safe to retry.
TF_REGISTRY_CLIENT_TIMEOUT
The default client timeout for requests to the remote registry is 10s. TF_REGISTRY_CLIENT_TIMEOUT can be configured and increased during exceptional circumstances.
TF_CLI_CONFIG_FILE
The location of the Terraform CLI configuration file.
Note that TERRAFORM_CONFIG is a deprecated alias for the TF_CLI_CONFIG_FILE variable. We recommend using TF_CLI_CONFIG_FILE instead of the deprecated TERRAFORM_CONFIG variable.
TF_PLUGIN_CACHE_DIR
The TF_PLUGIN_CACHE_DIR environment variable is an alternative way to set the plugin_cache_dir setting in the CLI configuration.
You can also use TF_PLUGIN_CACHE_MAY_BREAK_DEPENDENCY_LOCK_FILE to activate the transitional compatibility setting plugin_cache_may_break_dependency_lock_file.
TF_IGNORE
If TF_IGNORE is set to "trace", Terraform will output debug messages to display ignored files and folders. This is useful when debugging large repositories with .terraformignore files.
For more details on .terraformignore, please see Excluding Files from Upload with .terraformignore.
HCP Terraform CLI Integration
The CLI integration with HCP Terraform lets you use HCP Terraform and Terraform Enterprise on the command line. The integration requires including a cloud block in your Terraform configuration. You can define its arguments directly in your configuration file or supply them through environment variables, which can be useful for non-interactive workflows like Continuous Integration (CI).
Refer to HCP Terraform Settings for a full list of cloud block environment variables.