https://github.com/antonbabenko/tfvars-annotations
[not-WIP] Update values in terraform.tfvars using annotations
https://github.com/antonbabenko/tfvars-annotations
annotations dynamic terraform terraform-scripts terraform-variables tfvars
Last synced: about 2 months ago
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[not-WIP] Update values in terraform.tfvars using annotations
- Host: GitHub
- URL: https://github.com/antonbabenko/tfvars-annotations
- Owner: antonbabenko
- License: mit
- Created: 2019-04-23T19:37:33.000Z (about 6 years ago)
- Default Branch: master
- Last Pushed: 2019-11-01T09:49:55.000Z (over 5 years ago)
- Last Synced: 2025-05-07T04:03:26.209Z (about 2 months ago)
- Topics: annotations, dynamic, terraform, terraform-scripts, terraform-variables, tfvars
- Language: Go
- Homepage:
- Size: 52.7 KB
- Stars: 24
- Watchers: 7
- Forks: 3
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Update values in terraform.tfvars using annotations
## This project has become redundant (yay!)
## The same functionality is available natively in Terragrunt since [version 0.19.20](https://github.com/gruntwork-io/terragrunt/releases/tag/v0.19.20) (released 15th of August 2019).
### See [PR #3](https://github.com/antonbabenko/tfvars-annotations/pull/3) for the explanation and some extra unreleased code if you want to continue developing this for Terraform.
---
[Terraform](https://www.terraform.io/) is awesome!
As of today, Terraform 0.11 and 0.12 support only static (known, fixed, already computed) values in `tfvars` files. There is no way to use Terraform interpolation functions, or data-sources inside `tfvars` files in Terraform to update values.
While working on [modules.tf](https://github.com/antonbabenko/modules.tf-lambda) (a tool which converts visual diagrams created with [Cloudcraft.co](https://cloudcraft.co/) into Terraform configurations), I had a need to generate code which would chain invocations of [Terraform AWS modules](https://github.com/terraform-aws-modules) and pass arguments between them without requiring any extra Terraform code as a glue. [Terragrunt](https://github.com/gruntwork-io/terragrunt) is a great fit for this, it allows to reduce amount of Terraform configurations by reusing Terraform modules and providing arguments as values in `tfvars` files.
Some languages I know have concepts like annotations and decorators, so at first I made a [shell script](https://github.com/antonbabenko/modules.tf-lambda/blob/v1.2.0/templates/terragrunt-common-layer/common/scripts/update_dynamic_values_in_tfvars.sh) which replaced values in `tfvars` based on annotations and was called by Terragrunt hooks. `tfvars-annotations` shares the same goal and it has no external dependencies (except `terraform` or `terragrunt`).
## Use cases
1. modules.tf and Terragrunt (recommended)
1. Terraform (not implemented yet)
1. General example - AMI ID, AWS region
## Features
1. Supported annotations:
- [x] terragrunt_output:
- `@tfvars:terragrunt_output.vpc.vpc_id`
- `@tfvars:terragrunt_output.security-group.this_security_group_id`
- [ ] terraform_output
- [ ] data-sources generic
1. Type wrapping:
- `to_list`: Wrap original value with `[]` to make it it as a list
## How to use
Run `tfvars-annotations` before `terraform plan, apply, refresh`.
It will process tfvars file in the current directory and set updated values.
E.g.:
$ tfvars-annotations examples/project1-terragrunt/eu-west-1/app
$ terraform plan
## How to disable processing entirely
Put `@tfvars:disable_annotations` anywhere in the `terraform.tfvars` to not process the file.
## Examples
See `examples` for some basics.
## To-do
1. Get values from other sources:
- data sources generic
- aws_account_id or aws_region data sources
2. terragrunt_outputs from stacks:
- in any folder
- in current region
3. cache values unless stack is changed/updated
4. functions (limit(2), to_list)
5. rewrite in go (invoke like this => update_dynamic_values_in_tfvars ${get_parent_tfvars_dir()}/${path_relative_to_include()})
6. make it much faster, less verbose
7. add dry-run flag
8. Proposed syntax:
- `@tfvars:terragrunt_output.security-group_5.this_security_group_id.to_list`
- `@tfvars:terragrunt_output.["eu-west-1/security-group_5"].this_security_group_id.to_list`
- `@tfvars:terragrunt_output.["global/route53-zones"].zone_id`
- `@tfvars:terragrunt_data.aws_region.zone_id`
- `@tfvars:terragrunt_data.aws_region[{current=true}].zone_id`
## Bugs
1. Add support for `maps` (and lists of maps). Strange bugs with rendering comments in wrong places.
## Installation
On OSX, install it with Homebrew (not enough github stars to get it to the official repo):
```
brew install -s HomebrewFormula/tfvars-annotations.rb
```
Alternatively, you can download a [release](https://github.com/antonbabenko/tfvars-annotations/releases) suitable for your platform and unzip it. Make sure the `tfvars-annotations` binary is executable, and you're ready to go.
You can also install it like this:
```
go get github.com/antonbabenko/tfvars-annotations
```
Or run it from source:
```
go run . -debug examples/project1-terragrunt/eu-west-1/app
go run . examples/project1-terragrunt/eu-west-1/app
```
## Release
1. Make GitHub Release: `hub release create v0.0.3`. Then Github Actions will build binaries and attach them to Github release.
2. Update Homebrew version in `HomebrewFormula/tfvars-annotations.rb`. Install locally - `brew install -s HomebrewFormula/tfvars-annotations.rb`
## Authors
This project is created and maintained by [Anton Babenko](https://github.com/antonbabenko) with the help from [different contributors](https://github.com/antonbabenko/tfvars-annotations/graphs/contributors).
[](https://twitter.com/antonbabenko)
## License
This work is licensed under MIT License. See LICENSE for full details.
Copyright (c) 2019 Anton Babenko