# Configuring a Resource After Creation

> Markdown source of <https://docs.calebsargeant.com/computing/terraform/getting-started/configuring-a-resource-after-creation/>.

## Terraform Syntax

- HashiCorp configuration language
- Why not JSON?
- Human readable and editable
- Configuration syntax and expressions
- Conditionals, functions, templates

### Blocks

``` text
#Basic block
block_type label_one label_two {
key = value
embedded_block {
key = value
}
}
#Example block
resource "aws_route_table" "route-table" {
  vpc_id = "id928310928"
  route {
    cidr_block = "0.0.0.0/0"
    gateway_id = "id128073987"
  }
}
```

### Object Types

``` text
#Different value types
string = "taco"
number = 5
bool = true
list = ["bean-taco", "beef-taco"]
map = {name = "Caleb", age = 27, loves_tacos = true}
```

### References

``` text
#Keyword reference
var.taco_day
aws_instance_taco_truck.name
local.taco_toppings.cheeses
module.taco_hut.locations
#Interpolation
taco_name = "calebs-${var.taco_type}"

#Strings, numbers, and bools
local.taco_count # returns the number

#Lists and maps
local.taco_toppings[2] #returns element 3

#Resource values
var.region #returns us-east-1
data.aws_availability_zones.azs.names[1] #returns 2nd AZ
```

## Provisioners

- Last resport
- Local or remote
- Creation or destruction
- Multiple provisioners
- What if it all goes wrong?

### Provisioner Example

``` text
provisioner "file" {
connection {
type = "ssh"
user = "root"
private_key = var.private_key
host = var.hostname
}
source = "/local/path/to/file.txt"
destination = "path/to/file.txt"
}
provisioner "local-exec" {
  command = "local command here"
}

provisioner "remote-exec" {
  scripts = ["lists", "of", "local", "scripts"]
}
```

## Variables and Tags & S3 Configuration

[modulefive.tf](https://github.com/CalebSargeant/Getting-Started-Terraform/blob/master/m5/modulefive.tf)