[GEM] Adds validation for Elasticsearch

Author: picandocodigo

elasticsearch/Rakefile

@@ -15,7 +15,9 @@
 # specific language governing permissions and limitations
 # under the License.
 
-require "bundler/gem_tasks"
+require 'bundler/gem_tasks'
+
+task(:default) { system 'rake --tasks' }
 
 desc 'Run unit tests'
 task test: 'test:spec'

elasticsearch/elasticsearch.gemspec

@@ -56,6 +56,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'rspec'
   s.add_development_dependency 'ruby-prof' unless defined?(JRUBY_VERSION) || defined?(Rubinius)
   s.add_development_dependency 'simplecov'
+  s.add_development_dependency 'webmock'
   s.add_development_dependency 'yard'
 
   s.description = <<-DESC.gsub(/^    /, '')

elasticsearch/lib/elasticsearch.rb

@@ -15,18 +15,79 @@
 # specific language governing permissions and limitations
 # under the License.
 
-require "elasticsearch/version"
-
+require 'elasticsearch/version'
 require 'elasticsearch/transport'
 require 'elasticsearch/api'
 
 module Elasticsearch
-  module Transport
-    class Client
-      include Elasticsearch::API
+  SECURITY_PRIVILEGES_VALIDATION_WARNING = 'The client is unable to verify that the server is Elasticsearch due to security privileges on the server side.'.freeze
+  NOT_ELASTICSEARCH_WARNING = 'The client noticed that the server is not Elasticsearch and we do not support this unknown product.'.freeze
+  YOU_KNOW_FOR_SEARCH = 'You know, for Search'.freeze
+
+  class Client
+    include Elasticsearch::API
+
+    def initialize(arguments = {}, &block)
+      @verified = false
+      @transport = Elasticsearch::Transport::Client.new(arguments, &block)
+    end
+
+    def method_missing(name, *args, &block)
+      if name == :perform_request
+        verify_elasticsearch unless @verified
+        @transport.perform_request(*args, &block)
+      else
+        super
+      end
+    end
+
+    private
+
+    def verify_elasticsearch
+      begin
+        response = @transport.perform_request('GET', '/')
+      rescue Elasticsearch::Transport::Transport::Errors::Unauthorized,
+             Elasticsearch::Transport::Transport::Errors::Forbidden
+        @verified = true
+        warn(SECURITY_PRIVILEGES_VALIDATION_WARNING)
+        return
+      end
+
+      verify_with_version_or_header(response)
+    end
+
+    def verify_with_version_or_header(response)
+      version = response.body.dig('version', 'number')
+      raise Elasticsearch::NotElasticsearchError if version.nil? || version < '6.0.0'
+
+      if version == '7.x-SNAPSHOT' || Gem::Version.new(version) >= Gem::Version.new('7.14-SNAPSHOT')
+        raise Elasticsearch::NotElasticsearchError unless response.headers['x-elastic-product'] == 'Elasticsearch'
+
+        @verified = true
+      elsif Gem::Version.new(version) > Gem::Version.new('6.0.0') &&
+         Gem::Version.new(version) < Gem::Version.new('7.0.0')
+        raise Elasticsearch::NotElasticsearchError unless
+          response.body.dig('version', 'tagline') == YOU_KNOW_FOR_SEARCH
+
+        @verified = true
+      elsif Gem::Version.new(version) >= Gem::Version.new('7.0.0') &&
+            Gem::Version.new(version) < Gem::Version.new('7.14-SNAPSHOT')
+        raise Elasticsearch::NotElasticsearchError unless
+          response.body.dig('version', 'tagline') == YOU_KNOW_FOR_SEARCH &&
+          response.body.dig('version', 'build_flavor') == 'default'
+
+        @verified = true
+      end
+    end
+  end
+
+  class NotElasticsearchError < StandardError
+    def initialize
+      super(NOT_ELASTICSEARCH_WARNING)
     end
   end
 end
+
 module Elastic
   # If the version is X.X.X.pre/alpha/beta, use X.X.Xp for the meta-header:
   def self.client_meta_version

elasticsearch/spec/integration/client_integration_spec.rb

@@ -14,12 +14,8 @@
 # KIND, either express or implied.  See the License for the
 # specific language governing permissions and limitations
 # under the License.
-ELASTICSEARCH_URL = ENV['TEST_ES_SERVER'] || "http://localhost:#{(ENV['PORT'] || 9200)}"
-raise URI::InvalidURIError unless ELASTICSEARCH_URL =~ /\A#{URI::DEFAULT_PARSER.make_regexp}\z/
-
-require 'elasticsearch'
+require 'spec_helper'
 require 'logger'
-require 'rspec'
 
 context 'Elasticsearch client' do
   let(:logger) { Logger.new($stderr) }
@@ -53,7 +49,7 @@
   end
 
   context 'Reports the right meta header' do
-    it 'Reports es service name and gem versio' do
+    it 'Reports es service name and gem version' do
       headers = client.transport.connections.first.connection.headers
       expect(headers['x-elastic-client-meta']).to match /^es=#{Elasticsearch::VERSION}/
     end

elasticsearch/spec/integration/validation_integration_spec.rb

@@ -0,0 +1,30 @@
+# Licensed to Elasticsearch B.V. under one or more contributor
+# license agreements. See the NOTICE file distributed with
+# this work for additional information regarding copyright
+# ownership. Elasticsearch B.V. 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 'spec_helper'
+require 'logger'
+
+describe 'Elasticsearch validation integration' do
+  it 'Validates for Elasticsearch > 7.14' do
+    client = Elasticsearch::Client.new(
+      host: ELASTICSEARCH_URL,
+      logger: Logger.new($stderr)
+    )
+    expect(client.instance_variable_get('@verified')).to be false
+    client.count
+    expect(client.instance_variable_get('@verified')).to be true
+  end
+end

elasticsearch/spec/spec_helper.rb

@@ -17,7 +17,9 @@
 
 require 'elasticsearch'
 require 'rspec'
-require 'webmock/rspec'
+
+ELASTICSEARCH_URL = ENV['TEST_ES_SERVER'] || "http://localhost:#{(ENV['PORT'] || 9200)}"
+raise URI::InvalidURIError unless ELASTICSEARCH_URL =~ /\A#{URI::DEFAULT_PARSER.make_regexp}\z/
 
 RSpec.configure do |config|
   config.formatter = :documentation