Extend prefix guard

CHANGELOG.md

@@ -1,3 +1,6 @@
+## 3.0.10
+  - Extend `spreadsheet_safe` prefix guard to '-', '+', and '@' [#27](https://github.com/logstash-plugins/logstash-output-csv/pull/27)
+
 ## 3.0.9
  - Fix: updates syntax to JRuby 9.4 [#25](https://github.com/logstash-plugins/logstash-output-csv/pull/25)
 

lib/logstash/outputs/csv.rb

@@ -66,6 +66,6 @@ def get_value(name, event)
 
   private
   def escape_csv(val)
-    (spreadsheet_safe && val.is_a?(String) && val.start_with?("=")) ? "'#{val}" : val
+    (spreadsheet_safe && val.is_a?(String) && val.start_with?(/[=+\-@]/)) ? "'#{val}" : val
   end
 end # class LogStash::Outputs::CSV

logstash-output-csv.gemspec

@@ -1,7 +1,7 @@
 Gem::Specification.new do |s|
 
   s.name            = 'logstash-output-csv'
-  s.version         = '3.0.9'
+  s.version         = '3.0.10'
   s.licenses        = ['Apache License (2.0)']
   s.summary         = "Writes events to disk in a delimited format"
   s.description     = "This gem is a Logstash plugin required to be installed on top of the Logstash core pipeline using $LS_HOME/bin/logstash-plugin install gemname. This gem is not a stand-alone program"

spec/outputs/csv_spec.rb

@@ -139,18 +139,24 @@
     let(:event_data) do
       {
         "f1" => "1+1",
-        "f2" => "=1+1"
+        "f2" => "=1+1",
+        "f3" => "+1+1",
+        "f4" => "-1+1",
+        "f5" => "@1+1"
       }
     end
     let(:events) do
       [ LogStash::Event.new(event_data) ]
     end
 
-    let(:options) { { "path" => tmpfile, "fields" => ["f1", "f2"] } }
+    let(:options) { { "path" => tmpfile, "fields" => ["f1", "f2", "f3", "f4", "f5"] } }
     it "escapes them correctly" do
       expect(csv_output.size).to eq(1)
       expect(csv_output[0][0]).to eq("1+1")
       expect(csv_output[0][1]).to eq("'=1+1")
+      expect(csv_output[0][2]).to eq("'+1+1")
+      expect(csv_output[0][3]).to eq("'-1+1")
+      expect(csv_output[0][4]).to eq("'@1+1")
     end
 
     context "when escaping is turned off" do