feat: add is_slave (unlike is_master)

.docker-test

@@ -21,4 +21,5 @@ gem build is_master.gemspec
 gem install "is_master-$(cat VERSION).gem"
 
 rubocop
-ruby ./test/test_cli.rb
+ruby ./test/test_cli_master.rb
+ruby ./test/test_cli_slave.rb

.travis.yml

@@ -11,4 +11,5 @@ install:
   - gem install is_master-$(cat VERSION).gem
 script:
   - rubocop
-  - ruby ./test/test_cli.rb
+  - ruby ./test/test_cli_master.rb
+  - ruby ./test/test_cli_slave.rb

bin/is_slave

@@ -0,0 +1,37 @@
+#!/usr/bin/env ruby
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+require 'socket'
+
+if ARGV.length < 2
+  puts 'is_slave execute a command when it determine that server is slave'
+  puts "Usage: #{$PROGRAM_NAME} [VIP|FILE] COMMAND"
+  puts '  VIP     - IP address expected to be master'
+  puts '  FILE    - File expected to be master'
+  puts '  COMMAND - Command to execute if host is slave'
+  exit 2
+end
+
+expected = ARGV[0]
+command  = ARGV[1..-1].join(' ')
+
+if !Socket.ip_address_list.map(&:ip_address).include?(expected) && !File.exist?(expected)
+  Kernel.exec(command)
+else
+  puts 'OK - I am master, i going to sleep'
+end

is_master.gemspec

@@ -11,7 +11,7 @@ Gem::Specification.new do |spec|
   spec.license       = 'Apache-2.0'
 
   spec.files         = %x(git ls-files -z).split("\x0")
-  spec.executables   = ['is_master']
+  spec.executables   = %w[is_master is_slave]
   spec.test_files    = spec.files.grep(%r{^(test|spec|features)/})
   spec.require_paths = ['lib']
 

test/test_cli_master.rb

@@ -1,6 +1,6 @@
 require 'test/unit'
 
-class TestCli < Test::Unit::TestCase
+class TestCliMaster < Test::Unit::TestCase
   def test_missing_arg
     output = %x(is_master 127.0.0.1)
     assert_match('Usage: ', output)

test/test_cli_slave.rb

@@ -0,0 +1,33 @@
+require 'test/unit'
+
+class TestCliSlave < Test::Unit::TestCase
+  def test_missing_arg
+    output = %x(is_slave 127.0.0.1)
+    assert_match('Usage: ', output)
+
+    output = %x(is_slave)
+    assert_match('Usage: ', output)
+  end
+
+  def test_slave_mode
+    output = %x(is_slave 10.255.255.0 echo 'GOOD!')
+    assert_match('GOOD!', output)
+  end
+
+  def test_master_mode
+    output = %x(is_slave 127.0.0.1 echo 'GOOD!')
+    assert_match('I am master', output)
+  end
+
+  def test_file_slave_mode
+    output = %x(is_slave /tmp/test.txt echo 'GOOD!')
+    assert_match('GOOD!', output)
+  end
+
+  def test_file_master_mode
+    File.write('/tmp/test.txt', '')
+    output = %x(is_slave /tmp/test.txt echo 'GOOD!')
+    assert_match('I am master', output)
+    File.unlink('/tmp/test.txt')
+  end
+end