Use Erubis to remove/convert Erb before parsing JSON

Gemfile.lock

@@ -1,12 +1,14 @@
 PATH
   remote: .
   specs:
-    ecology (0.0.11)
+    ecology (0.0.12)
+      erubis
       multi_json
 
 GEM
   remote: http://rubygems.org/
   specs:
+    erubis (2.7.0)
     minitest (2.3.0)
     mocha (0.9.12)
     multi_json (1.0.3)

TODO

@@ -1,5 +1,3 @@
-* Use Erubis before evaluating
-
 * On Ecology.read calls, make sure ecology filename hasn't changed (and warn if it has)
 
 * Have Ecology.read try to do a read relative to the executable's directory first rather than relative to cwd.

ecology.gemspec

@@ -28,6 +28,7 @@ EOS
   s.require_paths = ["lib"]
 
   s.add_dependency "multi_json"
+  s.add_dependency "erubis"
 
   s.add_development_dependency "bundler", "~> 1.0.10"
   s.add_development_dependency "scope", "~> 0.2.1"

lib/ecology.rb

@@ -39,10 +39,15 @@ def read(ecology_pathname = nil)
       mutex.synchronize do
         return if @ecology_initialized
 
-        file_path = ENV['ECOLOGY_SPEC'] || ecology_pathname || default_ecology_name
-        if File.exist?(file_path)
-          @data = {}
-          contents = merge_with_overrides(file_path)
+        filelist = [ENV["ECOLOGY_SPEC"], ecology_pathname, default_ecology_name]
+        filelist.detect do |file_path|
+          if file_path && (File.exist?(file_path) || File.exist?(file_path + ".erb"))
+            @data = {}
+            contents = merge_with_overrides(file_path)
+            true
+          else
+            false
+          end
         end
 
         @application ||= File.basename($0)
@@ -103,7 +108,18 @@ def publish_event(event)
     end
 
     def merge_with_overrides(file_path)
-      contents = File.read(file_path)
+      if File.exist?(file_path + ".erb")
+        contents = File.read(file_path + ".erb")
+
+        require "erubis"
+        var_hash = {
+          :ecology_version => Ecology::VERSION,
+          :filename => "#{file_path}.erb",
+        }
+        contents = Erubis::Eruby.new(contents).result(var_hash)
+      else
+        contents = File.read(file_path)
+      end
       file_data = MultiJson.decode(contents);
 
       return unless file_data

test/ecology_test.rb

@@ -16,6 +16,7 @@ class EcologyTest < Scope::TestCase
 
     should "respect the ECOLOGY_SPEC environment variable" do
       ENV['ECOLOGY_SPEC'] = '/tmp/bobo.txt'
+      File.expects(:exist?).with('/tmp/bobo.txt.erb').returns(false).at_least_once
       File.expects(:exist?).with('/tmp/bobo.txt').returns(true)
       File.expects(:read).with('/tmp/bobo.txt').returns('{ "application": "foo_app" }')
       Ecology.read
@@ -31,6 +32,7 @@ class EcologyTest < Scope::TestCase
       $0 = "whatever_app.rb"
 
       ENV['ECOLOGY_SPEC'] = nil
+      File.expects(:exist?).with("whatever_app.ecology.erb").returns(false).at_least_once
       File.expects(:exist?).with("whatever_app.ecology").returns(false)
 
       Ecology.read

test/erubis_test.rb

@@ -0,0 +1,46 @@
+require File.join(File.dirname(__FILE__), "test_helper.rb")
+require "multi_json"
+
+class ErubisTest < Scope::TestCase
+  setup do
+    Ecology.reset
+  end
+
+  context "with a .erb ecology" do
+    setup do
+      set_up_ecology(<<ECOLOGY_CONTENTS, "some_app.ecology.erb")
+{
+  "application": "SomeApp",
+  "domain": {
+    "property1" :
+      <% if ENV["BOBO"] %>
+        37
+      <% else %>
+        42
+      <% end %>
+  },
+  "bobo": <%= MultiJson.encode(ENV["BOBO"]) %>
+}
+ECOLOGY_CONTENTS
+
+      ENV["BOBO"] = nil
+    end
+
+    should "Parse conditionally with Erubis" do
+      ENV["BOBO"] = "true"
+      Ecology.read
+      assert_equal 37, Ecology.property("domain::property1")
+    end
+
+    should "Parse conditionally with Erubis when a variable is unset" do
+      Ecology.read
+      assert_equal 42, Ecology.property("domain::property1")
+    end
+
+#    should "Return values from Erubis" do
+#      ENV["BOBO"] = { "a" => "b", "c" => "d" }
+#      Ecology.read
+#      assert_equal { "a" => "b", "c" => "d" }, Ecology.property("bobo")
+#    end
+  end
+end

test/test_helper.rb

@@ -10,7 +10,15 @@
 
 class Scope::TestCase
   def set_up_ecology(file_contents, filename = "some.ecology")
-    ENV["ECOLOGY_SPEC"] = filename
+    match = filename.match(/^(.*)\.erb$/)
+    if match
+      ENV["ECOLOGY_SPEC"] = match[1]
+      File.stubs(:exist?).with(match[1]).returns(false)
+    else
+      ENV["ECOLOGY_SPEC"] = filename
+    end
+
+    File.stubs(:exist?).with(filename + ".erb").returns(false)
     File.stubs(:exist?).with(filename).returns(true)
     File.expects(:read).with(filename).returns(file_contents).at_least_once
   end

test/trigger_test.rb

@@ -1,6 +1,6 @@
 require File.join(File.dirname(__FILE__), "test_helper.rb")
 
-class EnvironmentTest < Scope::TestCase
+class TriggerTest < Scope::TestCase
   setup do
     Ecology.reset
   end