Support for renamed redis commands

fixes #29

Author: houtmanj

CHANGELOG.md

@@ -1,3 +1,6 @@
+## Unreleased 
+  - Add support for renamed redis commands #29
+
 ## 3.3.0
   - Add channel to the event #46
 

docs/index.asciidoc

@@ -53,6 +53,7 @@ This plugin supports the following configuration options plus the <<plugins-{typ
 | <<plugins-{type}s-{plugin}-ssl>> |<<boolean,boolean>>|No
 | <<plugins-{type}s-{plugin}-threads>> |<<number,number>>|No
 | <<plugins-{type}s-{plugin}-timeout>> |<<number,number>>|No
+| <<plugins-{type}s-{plugin}-command_map>> |<<hash,hash>>|No
 |=======================================================================
 
 Also see <<plugins-{type}s-{plugin}-common-options>> for a list of options supported by all
@@ -154,7 +155,15 @@ Enable SSL support.
 
 Initial connection timeout in seconds.
 
+[id="plugins-{type}s-{plugin}-command_map"]
+===== `command_map`
 
+  * Value type is <<hash,hash>>
+  * There is no default value for this setting.
+  * key is the default command name, value is the renamed command.
+
+Configure renamed redis commands in the form of "oldname" => "newname".
+Redis allows for the renaming or disabling of commands in its protocol, see:  https://redis.io/topics/security
 
 [id="plugins-{type}s-{plugin}-common-options"]
 include::{include_path}/{type}.asciidoc[]

lib/logstash/inputs/redis.rb

@@ -56,9 +56,12 @@ module LogStash module Inputs class Redis < LogStash::Inputs::Threadable
   # The number of events to return from Redis using EVAL.
   config :batch_count, :validate => :number, :default => 125
 
+  # Redefined Redis commands to be passed to the Redis client.
+  config :command_map, :validate => :hash, :default => {}
+
   public
   # public API
-  # use to store a proc that can provide a redis instance or mock
+  # use to store a proc that can provide a Redis instance or mock
   def add_external_redis_builder(builder) #callable
     @redis_builder = builder
     self
@@ -151,18 +154,27 @@ def internal_redis_builder
   # private
   def connect
     redis = new_redis_instance
+
+    # register any renamed Redis commands
+    if @command_map and not @command_map.empty?
+      client_command_map = redis.client.command_map
+      @command_map.each do |name, renamed|
+        client_command_map[name.to_sym] = renamed.to_sym
+      end
+    end
+
     load_batch_script(redis) if batched? && is_list_type?
     redis
   end # def connect
 
   # private
   def load_batch_script(redis)
     #A Redis Lua EVAL script to fetch a count of keys
-      redis_script = <<EOF
-        local batchsize = tonumber(ARGV[1])
-        local result = redis.call('lrange', KEYS[1], 0, batchsize)
-        redis.call('ltrim', KEYS[1], batchsize + 1, -1)
-        return result
+    redis_script = <<EOF
+      local batchsize = tonumber(ARGV[1])
+      local result = redis.call(\'#{@command_map.fetch('lrange', 'lrange')}\', KEYS[1], 0, batchsize)
+      redis.call(\'#{@command_map.fetch('ltrim', 'ltrim')}\', KEYS[1], batchsize + 1, -1)
+      return result
 EOF
     @redis_script_sha = redis.script(:load, redis_script)
   end

logstash-input-redis.gemspec

@@ -76,6 +76,7 @@ def process(conf, event_count)
   let(:cfg) { {'key' => 'foo', 'data_type' => data_type, 'batch_count' => batch_count} }
   let(:quit_calls) { [:quit] }
   let(:accumulator) { [] }
+  let(:command_map) { {} }
 
   subject do
     LogStash::Plugin.lookup("input", "redis")
@@ -88,6 +89,71 @@ def process(conf, event_count)
     end
   end
 
+  context 'renamed redis commands' do
+    let(:cfg) {
+      {'key' => 'foo',
+      'data_type' => data_type,
+      'command_map' =>
+        {
+        'blpop' => 'testblpop',
+        'evalsha' => 'testevalsha',
+        'lrange' => 'testlrange',
+        'ltrim' => 'testltrim',
+        'script' => 'testscript',
+        'subscribe' => 'testsubscribe',
+        'psubscribe' => 'testpsubscribe',
+        },
+        'batch_count' => 2
+      }
+    }
+
+    before do
+      subject.register
+      allow(redis).to receive(:connected?)
+      allow(redis).to receive(:client).and_return(connection)
+      allow(connection).to receive(:command_map).and_return(command_map)
+    end
+
+    it 'sets the renamed commands in the command map' do
+      allow(redis).to receive(:script)
+      allow(redis).to receive(:evalsha).and_return([])
+
+      tt = Thread.new do
+        sleep 0.01
+        subject.do_stop
+      end
+
+      subject.run(accumulator)
+      tt.join
+
+      expect(command_map[:blpop]).to eq cfg['command_map']['blpop'].to_sym
+      expect(command_map[:evalsha]).to eq cfg['command_map']['evalsha'].to_sym
+      expect(command_map[:lrange]).to eq cfg['command_map']['lrange'].to_sym
+      expect(command_map[:ltrim]).to eq cfg['command_map']['ltrim'].to_sym
+      expect(command_map[:script]).to eq cfg['command_map']['script'].to_sym
+      expect(command_map[:subscribe]).to eq cfg['command_map']['subscribe'].to_sym
+      expect(command_map[:psubscribe]).to eq cfg['command_map']['psubscribe'].to_sym
+    end
+
+    it 'loads the batch script with the renamed command' do
+      capture = nil
+      allow(redis).to receive(:script) { |load, lua_script| capture = lua_script }
+      allow(redis).to receive(:evalsha).and_return([])
+
+      tt = Thread.new do
+        sleep 0.01
+        subject.do_stop
+      end
+
+      subject.run(accumulator)
+      tt.join
+
+      expect(capture).to include "redis.call('#{cfg['command_map']['lrange']}', KEYS[1], 0, batchsize)"
+      expect(capture).to include "redis.call('#{cfg['command_map']['ltrim']}', KEYS[1], batchsize + 1, -1)"
+    end
+  end
+
+
   context 'runtime for list data_type' do
     before do
       subject.register