Add variable support to Terraform examples (#196)

app/_includes/components/entity_example/format/snippets/terraform.md

@@ -28,3 +28,16 @@ resource "{{ include.presenter.resource_name }}" "my_{{ include.presenter.entity
 }
 ```
 {% endif %}
+
+{% if include.presenter.variable_names.size > 0 %}
+
+This example requires the following variables to be added to your manifest. You can specify values at runtime by setting `TF_VAR_name=value`.
+
+```
+{% for variable in include.presenter.variable_names -%}
+variable "{{ variable }}" {
+  type = string
+}
+{% endfor -%}
+```
+{% endif %}

app/_plugins/drops/entity_example/presenters/terraform.rb

@@ -9,7 +9,10 @@ module Presenters
         module Terraform
           class Base < Presenters::Base
             def data
-              @data ||= @example_drop.data
+              @data ||= Utils::VariableReplacer::TerraformData.run(
+                data: @example_drop.data,
+                variables: variables
+              )
             end
 
             def target
@@ -92,6 +95,8 @@ def line(input, depth, eol = "\n")
             def quote(input)
               return '' if input.nil?
 
+              return input if input.is_a?(String) && input.start_with?("var.")
+
               return input if ['true', 'false', true, false].include?(input)
 
               return input if input.is_a?(Numeric)
@@ -114,7 +119,18 @@ def template_file
 
           class Plugin < Base
             def data
-              @data ||= @example_drop.data.except(*targets.keys)
+              @data ||= Utils::VariableReplacer::TerraformData.run(
+                data: @example_drop.data.except(*targets.keys),
+                variables: variables
+              )
+            end
+
+            def variable_names
+              keys = []
+              variables.each do |k, v|
+                keys = v['value'].gsub("$","").downcase
+              end
+              keys
             end
           end
         end

app/_plugins/drops/entity_example/utils/variable_replacer.rb

@@ -61,6 +61,18 @@ def replace_variable(variable)
               "${{ env \"#{env_variable}\" }}"
             end
           end
+
+          class TerraformData < Data
+            def replace_variable(variable)
+              value = super
+
+              return nil unless value
+
+              env_variable = value.gsub('$', '').downcase
+              "var.#{env_variable}"
+            end
+          end
+
         end
       end
     end