terraform block types

terraform

• backend used to store state -> default is local mutually exclusive with cloud examples: remote, s3, azurerm, consul config is specific to the type
• cloud config: organization hostname workspaces
• required_providers name source aliases
• provider-meta seen as experiemental -> example is to use it to gather statistics on the provider usage

provider

- config is based on the provider schema
- expressions: use variables but no resources/data can be used
- meta-arguments
    alias
    version -> depreciated
    source/count/for_each/depends_on -> not expected

variable

- like function arguments
- meta-arguments
    default
    type (string, number, bool, list<TYPE>, set<TYPE>, map<TYPE>, object)
    description
    validation
    sensitive -> 
    nullable
- variables can be assigned using -var or .tfvars files
- idea is to use KRM here
- cannot have expressions

locals

- like local variables -> can use expressions
- can have expressions

output

- like function outputs -> expose variables to the other module
- meta-arguments
    - value -> expression
    - description
    - sensitive
    - depends_on
    - precondition
    - postcondition

module

- meta-arguments:
   - version
   - source = "./aws_vpc" (mandatory)
        -> europe-docker.pkg.dev/srlinux/eu.gcr.io/<TYPE>:<VERSION>
        -> [<HOSTNAME>/]<NAMESPACE>/<TYPE>
            HOSTNAME: registry.terraform.io
            NAMESPACE: An organizational namespace within the specified registry
            TYPE: typically the provider 
        -> ./,,, -> local path
        -> hashicorp/conusl/aws -> registry (app.terraform.io/example-corp/k8s-cluster/azurerm)
        supported:
            - local
            - registry
            - github/bitbucket/git
            - s3
            - gcs
   - providers = { aws = aws.west }
   - for_each
   - count
   - depends_on
   - <dynamic input variables>

resource

- meta-arguments:
    provider
    count
    for_each mutually exclusive with count
    depends_on
    lifecycle
        create_before_destroy
        prevent_destroy
        replace_triggered_by
        ignore_changes
    precondition
    postcondition
    connection
    provisioner

data

- meta-arguments:
    -> see resource

moved

- to deal with module resource changes
- meta-arguments:
    from
    to

import

- Use the import block to import existing infrastructure resources into Terraform, bringing them under Terraform's management
- Not sure if we need this as a resource will do this for us

check