Merge remote branch 'iconoclast/master'

doc/site/src/options.page

@@ -38,6 +38,8 @@ publisher:
     on_event:
   rss:
     file:
+    channel_link:
+    keep:
     on_event:
   campfire:
     url:

lib/cerberus/config.example.yml

@@ -23,6 +23,8 @@ publisher:
 #    url: http://someemail:password@cerberustool.campfirenow.com/room/51660
 #  rss:
 #    file: /usr/www/rss.xml
+#    channel_link: http://example.com/rss.xml
+#    keep: 1
 #  extra_subject: "#deployment #tags"
 #builder:
 #  rake:

lib/cerberus/publisher/rss.rb

@@ -1,29 +1,41 @@
 require 'cerberus/publisher/base'
 require 'time'
 require 'builder'
+require 'rss'
 
 class Cerberus::Publisher::RSS < Cerberus::Publisher::Base
   def self.publish(state, manager, options)
     config = options[:publisher, :rss]
     subject,body = Cerberus::Publisher::Base.formatted_message(state, manager, options)
 
-    pub_date = Time.now.iso8601
-    description = "<pre>#{body}</pre>".to_xs
-    result = <<-END
-<rss version="2.0">
-  <channel>
-    <title>Cerberus build feed for #{options[:application_name].to_xs}</title>
-    <pubDate>#{pub_date}</pubDate>
-    <generator>http://rubyforge.org/projects/cerberus</generator>
-    <item>
-      <title>#{subject.to_xs}</title>
-      <pubDate>#{pub_date}</pubDate>
-      <description>#{description}</description>
-    </item>
-  </channel>
-</rss>
-    END
+    pub_date = Time.now
 
-    IO.write(config[:file], result)
+    begin
+      feed = RSS::Parser.parse(File.read(config[:file]), false)
+      raise RSS::Error unless feed
+      keep = config[:keep] || 1
+      feed.items.slice!(keep -1 ..-1)  # one less than keep value, to make room for the new build
+    rescue RSS::Error, Errno::ENOENT
+      # if there's no existing file or we can't parse it, start a new one from scratch
+      feed = RSS::Maker.make("2.0") do |new_rss|
+        new_rss.channel.title = "#{options[:application_name].to_xs} build status"
+        new_rss.channel.description = "Cerberus build feed for #{options[:application_name].to_xs}"
+        new_rss.channel.generator = "http://rubyforge.org/projects/cerberus"
+        new_rss.channel.link = config[:channel_link] || "file://#{config[:file]}"
+      end
+    end
+
+    # update channel link if we have it explicitly set, otherwise retain existing value
+    feed.channel.link = config[:channel_link] unless config[:channel_link].nil?
+    feed.channel.pubDate = pub_date
+
+    new_item = RSS::Rss::Channel::Item.new()
+    new_item.title = subject
+    new_item.pubDate = pub_date
+    new_item.description = "<pre>#{body}</pre>"
+
+    feed.items.unshift new_item
+
+    IO.write(config[:file], feed)
   end
 end