How to quickly test pure-Ruby Grok pattern strings

test_grok.rb

# Obtain pure-Ruby lib
require 'grok-pure'

# Create grok instance
grok = Grok.new

# Map some regex patterns to pattern names; this sets up %{FOO}
grok.add_pattern("FOO", "[abc]")

# And/or load from file -- highly useful is the patterns/grok-patterns file that ships with Logstash source
# grok.add_patterns_from_file('/path/to/pattern/file')

# Actually tell it what you want to search for
grok.compile("lol %{FOO:foo1} %{FOO:foo2}")

# Finally, test that compiled pattern against input strings
result = grok.match("lol wut")

# And examine the result: it'll be 'false' if no match, or a Match object otherwise.
# Match objects exhibit e.g. a 'captures' attribute which is relatively self-evident
# when printed via 'p result' or 'puts result.inspect'
p result # => false
p grok.match("lol a b").captures # => {"FOO:foo1"=>["a"], "FOO:foo2"=>["b"]}