data_source_yaml_to_json.md

data "yaml_to_json"

Overview

A data source to convert yaml to json that is meant to be used with jsondecode in Terraform 0.12.

Terraform v0.12 comes with a support for complex types but there doesn't seem to be a way to leverage dynamic types on the level of providers as they have to define static schemas for all resources and data sources. This restriction doesn't apply to built-in functions though and therefore one can generate a "dynamic type" with jsondecode. The yaml_to_json resources bridges the gap all the way to YAML by providing means of converting YAML to JSON so that it can be parsed with jsondecode.

The yaml_to_json data source works even with earlier versions of Terraform but one can leverage jsondecode only starting from v0.12.

Arguments

The following arguments are supported:

• input - (Required, String) YAML document to process

Attributes

The following attribute is exported:

• output - (String) JSON representation of the YAML input

Limitations

Boolean Conversion

The underlying parser converts y into a boolean that can be serialized as a true. For instance {foo: y} will be parsed as {foo: true}. In order to avoid such behavior prefer using explicit string declaration with quotes: {foo: "y"}.

Usage Example

Configure

data "yaml_to_json" "doc" {
  input = <<EOF
foo: 123
456: bar
columns:
  - name: column0
    type: boolean
  - name: column1
    type: integer
EOF

}

output "json" {
  value = data.yaml_to_json.doc.output
}

output "result" {
  value = jsondecode(data.yaml_to_json.doc.output)
}

Apply

$ terraform apply
  data.yaml_to_json.doc: Refreshing state...
  
  Apply complete! Resources: 0 added, 0 changed, 0 destroyed.
  
  Outputs:
  
  json = {"456":"bar","columns":[{"name":"column0","type":"boolean"},{"name":"column1","type":"integer"}],"foo":123}
  result = {
    "456" = "bar"
    "columns" = [
      {
        "name" = "column0"
        "type" = "boolean"
      },
      {
        "name" = "column1"
        "type" = "integer"
      },
    ]
    "foo" = 123
  }