TALK.md

Plan for Terragrunt talk

0. Infrastructure as code == Terraform
1. Intro and use cases - https://github.com/gruntwork-io/terragrunt
2. Demo:

• sample repos:

  • https://github.com/terraform-aws-modules/meta
  • https://github.com/antonbabenko/terragrunt-reference-architecture
  • https://github.com/antonbabenko/modules.tf-demo

• code structure

  • group by logical provider's mental model (AWS = account/region/env/proj)
  • group by working area (eg, all AWS Lambda functions inside "lambdas" folder)
  • service-provider oriented VS application-oriented approach

• IAM roles (direnv)

• Terragrunt hooks ( https://github.com/terraform-aws-modules/meta/blob/master/github/terragrunt.hcl#L6 )

• dependencies

• dependency

• apply-all, plan-all, validate-all

• atlantis / makefile

• pre-commit, terraform-docs

• patterns:

  • include files (hierarchy, internal (specific) + high-level (general))
  • modules (local => PR to origin => external repo)
  • extend Terragrunt with Terraform (workaround for passing providers or other limits, terraform does not support CLI for providers, for eg)
  • use module placeholder to get remote_state benefits
  • tfvars = static, but inputs in terragrunt.hcl has full support for expressions and functions
  • depends_on with modules = native dependency output with TG

• complains & limitations:

  • verbosity in outputs
  • multiple providers (possible, but hard)
  • for_each with modules
  • circular dependencies between modules (eg, AWS Lambda + API Gateway + Permissions)
  • lots of various issues and bugs when doing complex things
  • terragrunt state

3. modules.tf