Lib improvements; simplified kite errors (#11)

* Lib improvements

- Added error module
- Added file checks

* Simplified Kite errors

lib/kite.rb

@@ -4,6 +4,7 @@
 
 require 'kite/version'
 require 'kite/helpers'
+require 'kite/error'
 
 require 'kite/base'
 require 'kite/core'

lib/kite/core.rb

@@ -17,7 +17,7 @@ def new(cloud_name)
     desc "generate", "Generate Cloud IaC from configuration"
     def generate()
       say "Generating Cloud #{ options[:cloud] } IaC", :green
-      @values = YAML.load(File.read('config/cloud.yml'))
+      @values = parse_cloud_config
 
       case options[:cloud]
       when 'aws'
@@ -54,7 +54,7 @@ def generate()
     desc 'render MANIFEST', 'Render manifest file from configuration and Terraform output'
     def render(manifest)
       say "Rendering #{ manifest } manifest", :green
-      @values = YAML.load(File.read('config/cloud.yml'))
+      @values = parse_cloud_config
       @tf_output = parse_tf_state('terraform/terraform.tfstate')
 
       case manifest

lib/kite/error.rb

@@ -0,0 +1,2 @@
+class Kite::Error < Thor::Error
+end

lib/kite/helpers.rb

@@ -1,9 +1,31 @@
 module Kite::Helpers
+  # Check config/cloud.yml file to be complete
+  def check_cloud_config(config)
+    raise Kite::Error, 'The config/cloud.yml is not filled out!' unless config.find { |key, hash| hash.find { |k, v| v.nil? } }.nil?
+  end
+
+  # Check if Terraform IaC was applied
+  def check_terraform_applied
+    raise Kite::Error, 'Did you terraform apply? terraform.tfstate is missing!' unless File.file? "terraform/terraform.tfstate"
+  end
+
   # Parse Terraform .tfstate file, returning the output hash
   def parse_tf_state(path)
-    tf_state = YAML.load(File.open(path))
+    check_terraform_applied
+
+    tf_state = YAML.load(File.read(path))
     tf_output = tf_state["modules"].first["outputs"]
     tf_output.map { |k, v| tf_output[k] = v["value"] }
+
     tf_output
   end
+
+  # Parse config/cloud.yml, returning the output hash
+  def parse_cloud_config
+    cloud_config = YAML.load(File.read('config/cloud.yml'))
+    check_cloud_config(cloud_config)
+
+    cloud_config
+  end
+
 end