add support for bird bgp peers

scripts/bird.rb

@@ -0,0 +1,39 @@
+#!/usr/bin/env ruby
+require_relative 'utils.rb'
+
+class BgpRegistry < Registry
+  def update_configs
+    template_name = data["host"]["bird"]["template_name"] rescue nil
+    template_name or die "bird.template_name not set for this host"
+
+    peers = data["network"]
+    v4_templ, v6_templ = generate_configs(template_name, peers)
+
+    bird_path = Pathname.new(File.expand_path("../../bird/", __FILE__))
+    atomic_write(bird_path.join("peers.conf"), v4_templ)
+    atomic_write(bird_path.join("peers6.conf"), v6_templ)
+  end
+
+  def generate_configs(template_name, peers)
+    template_path = Pathname.new(File.expand_path("../../templates", __FILE__))
+    template = Template.new(template_path.join("bird.conf.erb"))
+    v4_peers = collect_bgp_peers(peers, template_name, :v4)
+    v6_peers = collect_bgp_peers(peers, template_name, :v6)
+    return template.render(peers: v4_peers), template.render(peers: v6_peers)
+  end
+
+  private
+  def collect_bgp_peers(peers, template_name, proto)
+    peers.map do |name, peer|
+      if peer["as"] && peer["#{proto}_tunnel"]
+        context = {
+          name: name,
+          template: template_name,
+          tunnel_ip: peer["#{proto}_tunnel"],
+          as: peer["as"]
+        }
+        TemplateContext.new(context)
+      end
+    end.compact!
+  end
+end

templates/bird.conf.erb

@@ -0,0 +1,5 @@
+<% peers.each do |peer| -%>
+protocol bgp <%= peer.name %> as <%= peer.template %> {
+  neighbor <%= peer.tunnel_ip %> as <%= peer.as %>;
+};
+<% end -%>