From ca858925de7bc4e150eea3d5023d37462da5dbe9 Mon Sep 17 00:00:00 2001
From: Dmitry Tsepelev <dmitry.a.tsepelev@gmail.com>
Date: Sun, 26 Feb 2023 12:47:35 +0300
Subject: [PATCH] Handle zero payload (#22)

---
 CHANGELOG.md                                  |  1 +
 lib/io_monitor/publishers/base_publisher.rb   |  6 +++---
 spec/io_monitor/publishers/shared_examples.rb | 11 +++++++++++
 3 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 18088db..f7da057 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,6 @@
 # Change log
 
+- [PR#22](https://github.com/DmitryTsepelev/io_monitor/pull/22) Handle zero payload ([@DmitryTsepelev])
 - [PR#17](https://github.com/DmitryTsepelev/io_monitor/pull/17) Prometheus publisher ([@maxshend])
 
 ## main
diff --git a/lib/io_monitor/publishers/base_publisher.rb b/lib/io_monitor/publishers/base_publisher.rb
index 12585cb..2c85676 100644
--- a/lib/io_monitor/publishers/base_publisher.rb
+++ b/lib/io_monitor/publishers/base_publisher.rb
@@ -16,15 +16,15 @@ def process_action(payload)
       (payload.keys - [:response]).each do |source|
         ratio = ratio(payload[:response], payload[source])
 
-        if ratio < IoMonitor.config.warn_threshold
-          publish(source, ratio)
-        end
+        publish(source, ratio) if ratio < IoMonitor.config.warn_threshold
       end
     end
 
     private
 
     def ratio(response_size, io_size)
+      return 0 if io_size.to_f.zero?
+
       response_size.to_f / io_size.to_f
     end
   end
diff --git a/spec/io_monitor/publishers/shared_examples.rb b/spec/io_monitor/publishers/shared_examples.rb
index 4559910..cecceb8 100644
--- a/spec/io_monitor/publishers/shared_examples.rb
+++ b/spec/io_monitor/publishers/shared_examples.rb
@@ -52,6 +52,17 @@
 
         publisher.process_action(payload)
       end
+
+      context "when io_payload_size is zero" do
+        let(:io_payload_size) { 0 }
+        let(:ratio) { 0 }
+
+        it "calls .publish method with source and ratio" do
+          expect(publisher).to receive(:publish).with(io_kind, ratio)
+
+          publisher.process_action(payload)
+        end
+      end
     end
   end
 end