Resource refs

lib/harp-runtime/interpreter.rb

@@ -94,7 +94,9 @@ def create(resource_name)
     if ! advance() then return self end
     @@logger.debug "Launching resource: #{resource_name}."
     resource = @resourcer.get resource_name
-    created = @mutator.create(resource_name, resource)
+    deps     = @resourcer.get_dep(resource_name)
+    deps.each {|ref| create(ref)}
+    created  = @mutator.create(resource_name, resource)
     created.harp_script = @harp_script
     result = {:create => resource_name}
     args = {:action => :create}

lib/harp-runtime/resourcer.rb

@@ -5,13 +5,17 @@
 module Harp
 
   require "json"
-
+  require "rgl/adjacency"
+  require "rgl/topsort"
+
   # Resourcer keeps track of defined resources and provides lookup over them.
   class Resourcer
 
     @@logger = Logging.logger[self]
 
     def initialize(harp_id)
+      @dep_graph = RGL::DirectedAdjacencyGraph[]
+      @dependencies = Hash.new []
       @harp_id = harp_id
       @resources = nil
       @config = nil
@@ -37,14 +41,45 @@ def get_existing(resource_name)
       @resources[resource_name]
     end
 
+    # Retrieve a resource dependency list from the set
+    def get_dep(resource_name)
+      @@logger.debug "Looking for : #{resource_name}'s dependencies"
+      @dependencies[resource_name]
+    end
+
     private
 
     def digest(content)
       json = JSON.parse(content)
       @config = json.has_key?("Config") ? json["Config"] : nil
       @resources = json.has_key?("Resources") ? json["Resources"] : nil
-      # TODO: parse into graph and determine dependencies.
+      parse_into_graph
     end
-  end
 
+
+    def parse_into_graph
+      @resources.each do |name, content|
+        match_deps(name, content, "ref")
+      end
+      unless @dep_graph.acyclic?
+          raise "Found circular dependency"
+      end
+    end
+
+    #Iterate over values to check for specified item
+    def match_deps(name, content, item)
+      content.each do |key, value|
+        if value.is_a?(Hash)
+            dep = value[item]
+            unless dep.nil?
+              content[key] = @resources.has_key?(dep) ? @resources[dep]["id"] : nil
+              @dependencies[name] += [dep]
+              @dep_graph.add_edge(dep, name)
+            end
+        end
+    end
+
+    end
+
+  end
 end

spec/lang_addon_spec.rb

@@ -47,4 +47,4 @@ def copy()
     results = interpreter.play("copy", interpreter_context)
     expect(results).not_to be_empty
   end
-end
+end

spec/reference_spec.rb

@@ -0,0 +1,50 @@
+require File.dirname(__FILE__) + '/spec_helper'
+require "rubygems"
+require "harp_runtime"
+require "evalhook"
+
+ADDON_SCRIPT = <<OUTER
+template = <<END
+{
+  "Config": {
+  },
+  "Resources": {
+    "lc1": {
+      "type": "Std::LaunchConfiguration",
+      "image_id": "ami-d0f89fb9",
+      "instance_type": "t1.micro",
+      "id": "langSpecLc"
+    },
+    "asg1": {
+      "type": "Std::AutoScalingGroup",
+      "id": "langSpecASG",
+      "launch_configuration_name": {"ref": "lc1"},
+      "availability_zones": "us-east-1",
+      "max_size": "1",
+      "min_size": "1"
+    }
+
+  }
+}
+END
+
+engine.consume(template)
+
+def create()
+  engine.create("asg1")
+end
+
+OUTER
+
+describe Harp::HarpInterpreter, "#play" do
+  let(:interpreter_context) do
+    c = create_interpreter_context()
+    c[:harp_contents] = ADDON_SCRIPT
+    c
+  end
+  let(:interpreter) { Harp::HarpInterpreter.new(interpreter_context()) }
+  it "handles refs" do
+    results = interpreter.play("create", interpreter_context)
+    expect(results).not_to be_empty
+  end
+end