JSON-e Terraform Provider

A provider with a single resource jsone_template. This works similarly to the template_file resource but allows us to use json-e constructs like $map to transforms lists and such things.

You can use the json-e documentation to find out more about how to use the templates.

Usage

First go get -u github.com/taskcluster/terraform-provider-jsone. At that point, if you have built terraform from source, simply running go install for this package will work. Otherwise, follow along with the official docs on how to use third party plugins.

Now it is as simple as:

locals {
  context = {
    foo = "bar"
    baz = ["bing", "qux"]
  }
}

data "jsone_template" "service" {
  template = "${file("${path.module}/service.yaml")}"
  yaml_context = "${jsonencode(local.context)}"
}

output "rendered" {
  value = "${data.jsone_template.service.rendered}"
}

The resource takes a string called template and either a field called context or yaml_context. These are mutually exclusive. context should be good enough for most cases and is just a terraform map, but if you run into issues with how terraform handles mixed-type maps or need to pass in typed data, opt for yaml_context which just takes a string containing yaml. Oftentimes using the terraform interpolation of jsonencode will be your best bet.

You can access the rendered template with .rendered much the same as with template_file. This will normally be in json format unless you explicitely pass in format = "yaml" to the resource.

Multiple Templates

In some cases, it is useful to have multiple templates in the input file. In this case, the rendered value is a list of JSON- (or YAML-) formatted rendered templates. Use the jsone_templates resource (note the plural) for this purpose.

# service.yaml
---
one: '{$eval: "17 - 16"}'
---
two: '{$eval: "12 / 6"}'

data "jsone_templates" "service" {
  template = "${file("${path.module}/service.yaml")}"
  yaml_context = "${jsonencode(local.context)}"
}

output "rendered" {
  value1 = "${data.jsone_template.service.rendered[0]}"
  # --> '{"one": 1}'
  value2 = "${data.jsone_template.service.rendered[1]}"
  # --> '{"two": 2}'
}

Extra Functions

This provider adds a base64encode() function to the context that can be used as follows:

foo: {$eval: "base64encode(something)"}

Development

Go requirements are the same as Terraform itself (currently 1.9).

In a clean GOPATH, go get github.com/taskcluster/terraform-provider-jsone, then switch to that directory and run go get -t ./... to get dependencies. Run go test ./.. to test.