add a re_contains filter for rgex string comparison

README.md

@@ -192,6 +192,7 @@ ones:
 | `typify` |  Converts string values into primitive types (int, float, bool) where applicable for a nested data structure |
 | `merge` |  Combines two hashes into one, a.l.a ruby merge |
 | `re_replace` |  Regexp search and replace, a.l.a ruby gsub, e.g. `"foo" | re_replace: "o+", "X"` |
+| `re_contains` |  Returns a boolean for the regexp compare against the string target, e.g. `"foo" | re_contains: "o+"` => `true` |
 
 The default `resource_templates` make use of the `context` attribute to allow
 simpler modification of some common fields.  These include:

lib/kubetruth/template.rb

@@ -207,6 +207,11 @@ def re_replace(string, pattern, replacement, flags="")
         string.gsub(Regexp.new(pattern, allflags), replacement)
       end
 
+      def re_contains(string, pattern, flags="")
+        allflags = flags.chars.inject(0) {|sum, n| sum | REGEXP_FLAGS[n] }
+        return (string =~ Regexp.new(pattern, allflags)) != nil
+      end
+
     end
 
     Liquid::Template.register_filter(CustomLiquidFilters)

spec/kubetruth/template_spec.rb

@@ -402,6 +402,24 @@ module Kubetruth
         end
 
       end
+
+      describe "#re_contains" do
+
+        it "performs match" do
+          expect(re_contains("foobar", "o+")).to eq(true)
+          expect(re_contains("foobar", "x+")).to eq(false)
+          expect(described_class.new('{{ "foobar" | re_contains: "o+" }}').render()).to eq("true")
+        end
+
+        it "handles flags" do
+          expect(re_contains("fOObar", "o+")).to eq(false)
+          expect(re_contains("fOObar", "o+", "i")).to eq(true)
+          expect(re_contains("FOO\nOO", "f.{5}", "i")).to eq(false)
+          expect(re_contains("FOO\nOO", "f.{5}", "mi")).to eq(true)
+        end
+
+      end
+
     end
 
     describe Kubetruth::Template::TemplateHashDrop do