Config file

An Infracost config file can be created in each of your Terraform project repos to specify how Infracost should be run. This has three main advantages over CLI flags:

Not having to remember or specify flags for each run.
Ability to run Infracost with multiple Terraform projects or workspaces, and combine them into the same breakdown or diff output.
Enable multi-project or workspace runs in CI/CD integrations.

Usage#

Create an infracost.yml file in each of your Terraform project repos. Each project can have the parameters mentioned in the table below; you might find the following examples helpful.
version: 0.1

projects:
- path: path/to/my_terraform
# other params
- path: another/project
Pass the file to the infracost breakdown or infracost diff using the --config-file option. This flag should not be confused with the --usage-file option that is used to define resource usage estimates.

Parameter	Description	Notes
`path`	Path to the Terraform directory or JSON/plan file	Required
`usage_file`	Path to Infracost usage file that specifies values for usage-based resources	Not required
`terraform_binary`	Used to change the path to the `terraform` binary	Not required, e.g. can be set to `terragrunt` or another path
`terraform_plan_flags`	Flags to pass to `terraform plan` with Terraform directory paths	Not required. Can be space delimited, e.g. `-var-file=prod.tfvars -var-file=us-east.tfvars`
`terraform_workspace`	Used to set the Terraform workspace	Not required. Only set this for multi-workspace deployments, otherwise it might result in the Terraform error "workspaces not supported"
`terraform_use_state`	Use Terraform state instead of generating a plan, useful if you want to see the breakdown of the current Terraform state.	Not required. Applicable when path is a Terraform directory. Can't be used with the `diff` command.
`terraform_cloud_host`	For Terraform Enterprise users, used to override the default `app.terraform.io` backend host	Not required
`terraform_cloud_token`	For Terraform Cloud/Enterprise users, set this to a Team API Token or User API Token so Infracost can use it to access the plan	Not required. If this environment variable is set, that'll be used for all projects instead of this parameter

Examples#

Multi-workspaces
Multi-projects
Terragrunt

version: 0.1

projects:
  - path: examples/terraform
    terraform_plan_flags: -var-file=prod.tfvars -var-file=us-east.tfvars 
    terraform_workspace: prod

  - path: examples/terraform
    terraform_plan_flags: -var-file=stage.tfvars
    terraform_workspace: stage

  - path: examples/terraform
    terraform_workspace: dev

If your requirements cannot be satisfied with a config file, please create an issue so we can understand the use-case. Also consider using these bash scripts that demonstrate how Infracost commands can be combined.

Precedence#

Infracost configuration values are chosen in this order:

CLI flags (run infracost --help to see them)
Environment variables
Config file