From 28af2b61481c2bc7af1e80d4a436ffc08ed6fd8f Mon Sep 17 00:00:00 2001
From: Saku Ytti <saku@ytti.fi>
Date: Sat, 12 Sep 2015 12:07:10 +0300
Subject: Fix FloatDomainError when 0 nodes are found

Oxidized would throw:
----
/var/lib/gems/2.1.0/gems/oxidized-0.7.2/lib/oxidized/jobs.rb:36:in `to_i': NaN (FloatDomainError)
        from /var/lib/gems/2.1.0/gems/oxidized-0.7.2/lib/oxidized/jobs.rb:36:in `new_count'
        from /var/lib/gems/2.1.0/gems/oxidized-0.7.2/lib/oxidized/jobs.rb:28:in `duration'
        from /var/lib/gems/2.1.0/gems/oxidized-0.7.2/lib/oxidized/jobs.rb:16:in `initialize'
        from /var/lib/gems/2.1.0/gems/oxidized-0.7.2/lib/oxidized/worker.rb:7:in `new'
        from /var/lib/gems/2.1.0/gems/oxidized-0.7.2/lib/oxidized/worker.rb:7:in `initialize'
        from /var/lib/gems/2.1.0/gems/oxidized-0.7.2/lib/oxidized/core.rb:21:in `new'
        from /var/lib/gems/2.1.0/gems/oxidized-0.7.2/lib/oxidized/core.rb:21:in `initialize'
        from /var/lib/gems/2.1.0/gems/oxidized-0.7.2/lib/oxidized/core.rb:12:in `new'
        from /var/lib/gems/2.1.0/gems/oxidized-0.7.2/lib/oxidized/core.rb:12:in `new'
        from /var/lib/gems/2.1.0/gems/oxidized-0.7.2/lib/oxidized/cli.rb:9:in `run'
        from /var/lib/gems/2.1.0/gems/oxidized-0.7.2/bin/oxidized:9:in `<top (required)>'
        from /usr/local/bin/oxidized:23:in `load'
        from /usr/local/bin/oxidized:23:in `<main>'
---

When nodes.size == 0, this may happen when you have say one node in router.db which has non-existing model. Actual problem happens in jobs.rb:

@duration = @durations.inject(:+).to_f / @nodes.size
...
@want = ((@nodes.size * @duration) / @interval).to_i

Simplified:

a = 0.0 / 0
b = a.to_i
---
 lib/oxidized/core.rb | 3 +++
 1 file changed, 3 insertions(+)

(limited to 'lib/oxidized')

diff --git a/lib/oxidized/core.rb b/lib/oxidized/core.rb
index b70443c..6e7a352 100644
--- a/lib/oxidized/core.rb
+++ b/lib/oxidized/core.rb
@@ -14,10 +14,13 @@ module Oxidized
   end
 
   class Core
+    class NoNodesFound < OxidizedError; end
+
     def initialize args
       Oxidized.mgr = Manager.new
       Oxidized.Hooks = HookManager.from_config CFG
       nodes        = Nodes.new
+      raise NoNodesFound, 'source returns no usable nodes' if nodes.size == 0
       @worker      = Worker.new nodes
       trap('HUP') { nodes.load }
       if CFG.rest?
-- 
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