From ae98055f3387cba23c71d13e37498ccaee1bb787 Mon Sep 17 00:00:00 2001
From: Kenji Okimoto <okimoto@clear-code.com>
Date: Mon, 12 Mar 2018 12:26:56 +0900
Subject: [PATCH 1/2] Support pattern start with character classes

In prevous version, following pattern raises syntax error:

    <filter>
      @type grep
      <regexp>
        key price
        pattern [1-9]\d*
      </regexp>
    </filter>

This example is derrived from
https://docs.fluentd.org/v1.0/articles/filter_grep#<regexp>-directive
---
 lib/fluent/plugin/filter_grep.rb | 12 ++++++++++--
 test/plugin/test_filter_grep.rb  | 14 ++++++++++++++
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/lib/fluent/plugin/filter_grep.rb b/lib/fluent/plugin/filter_grep.rb
index d289de70f2..87a5d378e6 100644
--- a/lib/fluent/plugin/filter_grep.rb
+++ b/lib/fluent/plugin/filter_grep.rb
@@ -41,7 +41,11 @@ def initialize
       config_param :key, :string
       desc "The regular expression."
       config_param :pattern do |value|
-        Regexp.compile(value)
+        if value.start_with?("/") and value.end_with?("/")
+          Regexp.compile(value[1..-2])
+        else
+          Regexp.compile(value)
+        end
       end
     end
 
@@ -50,7 +54,11 @@ def initialize
       config_param :key, :string
       desc "The regular expression."
       config_param :pattern do |value|
-        Regexp.compile(value)
+        if value.start_with?("/") and value.end_with("/")
+          Regexp.compile(value[1..-2])
+        else
+          Regexp.compile(value)
+        end
       end
     end
 
diff --git a/test/plugin/test_filter_grep.rb b/test/plugin/test_filter_grep.rb
index 2eb6dba178..5f97d38470 100644
--- a/test/plugin/test_filter_grep.rb
+++ b/test/plugin/test_filter_grep.rb
@@ -73,6 +73,20 @@ def create_driver(conf = '')
         end
       end
     end
+
+    sub_test_case "pattern with slashes" do
+      test "start with character classes" do
+        conf = %[
+          regexp1 message test
+          <regexp>
+            key message
+            pattern /[a-z]test/
+          </regexp>
+        ]
+        d = create_driver(conf)
+        assert_equal(/[a-z]test/, d.instance.regexps.first.pattern)
+      end
+    end
   end
 
   sub_test_case 'filter_stream' do

From bdf4de288e82f9e84cb88aec554d1b151005ddd3 Mon Sep 17 00:00:00 2001
From: Kenji Okimoto <okimoto@clear-code.com>
Date: Tue, 13 Mar 2018 09:28:09 +0900
Subject: [PATCH 2/2] Remove garbage line

---
 test/plugin/test_filter_grep.rb | 1 -
 1 file changed, 1 deletion(-)

diff --git a/test/plugin/test_filter_grep.rb b/test/plugin/test_filter_grep.rb
index 5f97d38470..18a40cd198 100644
--- a/test/plugin/test_filter_grep.rb
+++ b/test/plugin/test_filter_grep.rb
@@ -77,7 +77,6 @@ def create_driver(conf = '')
     sub_test_case "pattern with slashes" do
       test "start with character classes" do
         conf = %[
-          regexp1 message test
           <regexp>
             key message
             pattern /[a-z]test/