Add preflight check on Elasticsearch before connecting

CHANGELOG.md

@@ -1,3 +1,6 @@
+## 11.2.0
+ - Added preflight checks on Elasticsearch [#1026](https://github.com/logstash-plugins/logstash-output-elasticsearch/pull/1026)
+
 ## 11.1.0
  - Feat: add `user-agent` header passed to the Elasticsearch HTTP connection [#1038](https://github.com/logstash-plugins/logstash-output-elasticsearch/pull/1038)
 

lib/logstash/outputs/elasticsearch/http_client/pool.rb

@@ -37,6 +37,9 @@ def message
     ROOT_URI_PATH = '/'.freeze
     LICENSE_PATH = '/_license'.freeze
 
+    VERSION_6_TO_7 = Gem::Requirement.new([">= 6.0.0", "< 7.0.0"])
+    VERSION_7_TO_7_14 = Gem::Requirement.new([">= 7.0.0", "< 7.14.0"])
+
     DEFAULT_OPTIONS = {
       :healthcheck_path => ROOT_URI_PATH,
       :sniffing_path => "/_nodes/http",
@@ -211,7 +214,7 @@ def sniffer_alive?
     def start_resurrectionist
       @resurrectionist = Thread.new do
         until_stopped("resurrection", @resurrect_delay) do
-          healthcheck!
+          healthcheck!(false)
         end
       end
     end
@@ -232,11 +235,18 @@ def health_check_request(url)
       perform_request_to_url(url, :head, @healthcheck_path)
     end
 
-    def healthcheck!
+    def healthcheck!(register_phase = true)
       # Try to keep locking granularity low such that we don't affect IO...
       @state_mutex.synchronize { @url_info.select {|url,meta| meta[:state] != :alive } }.each do |url,meta|
         begin
           health_check_request(url)
+
+          # when called from resurrectionist skip the product check done during register phase
+          if register_phase
+            if !elasticsearch?(url)
+              raise LogStash::ConfigurationError, "Could not connect to a compatible version of Elasticsearch"
+            end
+          end
           # If no exception was raised it must have succeeded!
           logger.warn("Restored connection to ES instance", url: url.sanitized.to_s)
           # We reconnected to this node, check its ES version
@@ -254,6 +264,42 @@ def healthcheck!
       end
     end
 
+    def elasticsearch?(url)
+      begin
+        response = perform_request_to_url(url, :get, ROOT_URI_PATH)
+      rescue ::LogStash::Outputs::ElasticSearch::HttpClient::Pool::BadResponseCodeError => e
+        return false if response.code == 401 || response.code == 403
+        raise e
+      end
+
+      version_info = LogStash::Json.load(response.body)
+      return false if version_info['version'].nil?
+
+      version = Gem::Version.new(version_info["version"]['number'])
+      return false if version < Gem::Version.new('6.0.0')
+
+      if VERSION_6_TO_7.satisfied_by?(version)
+        return valid_tagline?(version_info)
+      elsif VERSION_7_TO_7_14.satisfied_by?(version)
+        build_flavor = version_info["version"]['build_flavor']
+        return false if build_flavor.nil? || build_flavor != 'default' || !valid_tagline?(version_info)
+      else
+        # case >= 7.14
+        lower_headers = response.headers.transform_keys {|key| key.to_s.downcase }
+        product_header = lower_headers['x-elastic-product']
+        return false if product_header != 'Elasticsearch'
+      end
+      return true
+    rescue => e
+      logger.error("Unable to retrieve Elasticsearch version", url: url.sanitized.to_s, exception: e.class, message: e.message)
+      false
+    end
+
+    def valid_tagline?(version_info)
+      tagline = version_info['tagline']
+      tagline == "You Know, for Search"
+    end
+
     def stop_resurrectionist
       @resurrectionist.join if @resurrectionist
     end

logstash-output-elasticsearch.gemspec

@@ -1,6 +1,6 @@
 Gem::Specification.new do |s|
   s.name            = 'logstash-output-elasticsearch'
-  s.version         = '11.1.0'
+  s.version         = '11.2.0'
 
   s.licenses        = ['apache-2.0']
   s.summary         = "Stores logs in Elasticsearch"
@@ -31,6 +31,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'flores'
   s.add_development_dependency 'cabin', ['~> 0.6']
   s.add_development_dependency 'webrick'
+  s.add_development_dependency 'webmock'
   # Still used in some specs, we should remove this ASAP
   s.add_development_dependency 'elasticsearch'
 end

spec/unit/outputs/elasticsearch/http_client/pool_spec.rb

@@ -50,28 +50,29 @@
 
     describe "healthcheck url handling" do
       let(:initial_urls) { [::LogStash::Util::SafeURI.new("http://localhost:9200")] }
+      before(:example) do
+        expect(adapter).to receive(:perform_request).with(anything, :get, "/", anything, anything) do |url, _, _, _, _|
+          expect(url.path).to be_empty
+        end
+      end
 
       context "and not setting healthcheck_path" do
         it "performs the healthcheck to the root" do
-          expect(adapter).to receive(:perform_request) do |url, method, req_path, _, _|
-            expect(method).to eq(:head)
+          expect(adapter).to receive(:perform_request).with(anything, :head, "/", anything, anything) do |url, _, _, _, _|
             expect(url.path).to be_empty
-            expect(req_path).to eq("/")
           end
-          subject.healthcheck!
+          expect { subject.healthcheck! }.to raise_error(LogStash::ConfigurationError, "Could not connect to a compatible version of Elasticsearch")
         end
       end
 
       context "and setting healthcheck_path" do
         let(:healthcheck_path) { "/my/health" }
         let(:options) { super().merge(:healthcheck_path => healthcheck_path) }
         it "performs the healthcheck to the healthcheck_path" do
-          expect(adapter).to receive(:perform_request) do |url, method, req_path, _, _|
-            expect(method).to eq(:head)
+          expect(adapter).to receive(:perform_request).with(anything, :head, eq(healthcheck_path), anything, anything) do |url, _, _, _, _|
             expect(url.path).to be_empty
-            expect(req_path).to eq(healthcheck_path)
           end
-          subject.healthcheck!
+          expect { subject.healthcheck! }.to raise_error(LogStash::ConfigurationError, "Could not connect to a compatible version of Elasticsearch")
         end
       end
     end
@@ -164,6 +165,20 @@
     end
   end
 
+  class MockResponse
+    attr_reader :code, :headers
+
+    def initialize(code = 200, body = nil, headers = {})
+        @code = code
+        @body = body
+        @headers = headers
+    end
+
+    def body
+      @body.to_json
+    end
+  end
+
   describe "connection management" do
     before(:each) { subject.start }
     context "with only one URL in the list" do
@@ -175,8 +190,17 @@
     end
 
     context "with multiple URLs in the list" do
+      let(:version_ok) do
+        MockResponse.new(200, {"tagline" => "You Know, for Search",
+                               "version" => {
+                                 "number" => '7.13.0',
+                                 "build_flavor" => 'default'}
+                               })
+      end
+
       before :each do
         allow(adapter).to receive(:perform_request).with(anything, :head, subject.healthcheck_path, {}, nil)
+        allow(adapter).to receive(:perform_request).with(anything, :get, subject.healthcheck_path, {}, nil).and_return(version_ok)
       end
       let(:initial_urls) { [ ::LogStash::Util::SafeURI.new("http://localhost:9200"), ::LogStash::Util::SafeURI.new("http://localhost:9201"), ::LogStash::Util::SafeURI.new("http://localhost:9202") ] }
 
@@ -220,8 +244,14 @@
       ::LogStash::Util::SafeURI.new("http://otherhost:9201")
     ] }
 
+    let(:valid_response) { MockResponse.new(200, {"tagline" => "You Know, for Search",
+                                                          "version" => {
+                                                            "number" => '7.13.0',
+                                                            "build_flavor" => 'default'}
+                                                          }) }
+
     before(:each) do
-      allow(subject).to receive(:perform_request_to_url).and_return(nil)
+      allow(subject).to receive(:perform_request_to_url).and_return(valid_response)
       subject.start
     end
 
@@ -240,6 +270,7 @@
   describe "license checking" do
     before(:each) do
       allow(subject).to receive(:health_check_request)
+      allow(subject).to receive(:elasticsearch?).and_return(true)
     end
 
     let(:options) do
@@ -273,6 +304,7 @@
 
     before(:each) do
       allow(subject).to receive(:health_check_request)
+      allow(subject).to receive(:elasticsearch?).and_return(true)
     end
 
     context "if ES doesn't return a valid license" do
@@ -319,3 +351,120 @@
     end
   end
 end
+
+describe "#elasticsearch?" do
+  let(:logger) { Cabin::Channel.get }
+  let(:adapter) { double("Manticore Adapter") }
+  let(:initial_urls) { [::LogStash::Util::SafeURI.new("http://localhost:9200")] }
+  let(:options) { {:resurrect_delay => 2, :url_normalizer => proc {|u| u}} } # Shorten the delay a bit to speed up tests
+  let(:es_node_versions) { [ "0.0.0" ] }
+  let(:license_status) { 'active' }
+
+  subject { LogStash::Outputs::ElasticSearch::HttpClient::Pool.new(logger, adapter, initial_urls, options) }
+
+  let(:url) { ::LogStash::Util::SafeURI.new("http://localhost:9200") }
+
+  context "in case HTTP error code" do
+    it "should fail for 401" do
+      allow(adapter).to receive(:perform_request)
+        .with(anything, :get, "/", anything, anything)
+        .and_return(MockResponse.new(401))
+
+      expect(subject.elasticsearch?(url)).to be false
+    end
+
+    it "should fail for 403" do
+      allow(adapter).to receive(:perform_request)
+              .with(anything, :get, "/", anything, anything)
+              .and_return(status: 403)
+      expect(subject.elasticsearch?(url)).to be false
+    end
+  end
+
+  context "when connecting to a cluster which reply without 'version' field" do
+    it "should fail" do
+      allow(adapter).to receive(:perform_request)
+                    .with(anything, :get, "/", anything, anything)
+                    .and_return(body: {"field" => "funky.com"}.to_json)
+      expect(subject.elasticsearch?(url)).to be false
+    end
+  end
+
+  context "when connecting to a cluster with version < 6.0.0" do
+    it "should fail" do
+      allow(adapter).to receive(:perform_request)
+                          .with(anything, :get, "/", anything, anything)
+                          .and_return(200, {"version" => { "number" => "5.0.0"}}.to_json)
+      expect(subject.elasticsearch?(url)).to be false
+    end
+  end
+
+  context "when connecting to a cluster with version in [6.0.0..7.0.0)" do
+    it "must be successful with valid 'tagline'" do
+      allow(adapter).to receive(:perform_request)
+                                .with(anything, :get, "/", anything, anything)
+                                .and_return(MockResponse.new(200, {"version" => {"number" => "6.5.0"}, "tagline" => "You Know, for Search"}))
+      expect(subject.elasticsearch?(url)).to be true
+    end
+
+    it "should fail if invalid 'tagline'" do
+      allow(adapter).to receive(:perform_request)
+                                .with(anything, :get, "/", anything, anything)
+                                .and_return(MockResponse.new(200, {"version" => {"number" => "6.5.0"}, "tagline" => "You don't know"}))
+      expect(subject.elasticsearch?(url)).to be false
+    end
+
+    it "should fail if 'tagline' is not present" do
+      allow(adapter).to receive(:perform_request)
+                                .with(anything, :get, "/", anything, anything)
+                                .and_return(MockResponse.new(200, {"version" => {"number" => "6.5.0"}}))
+      expect(subject.elasticsearch?(url)).to be false
+    end
+  end
+
+  context "when connecting to a cluster with version in [7.0.0..7.14.0)" do
+    it "must be successful is 'build_flavor' is 'default' and tagline is correct" do
+      allow(adapter).to receive(:perform_request)
+                                .with(anything, :get, "/", anything, anything)
+                                .and_return(MockResponse.new(200, {"version": {"number": "7.5.0", "build_flavor": "default"}, "tagline": "You Know, for Search"}))
+      expect(subject.elasticsearch?(url)).to be true
+    end
+
+    it "should fail if 'build_flavor' is not 'default' and tagline is correct" do
+      allow(adapter).to receive(:perform_request)
+                                .with(anything, :get, "/", anything, anything)
+                                .and_return(MockResponse.new(200, {"version": {"number": "7.5.0", "build_flavor": "oss"}, "tagline": "You Know, for Search"}))
+      expect(subject.elasticsearch?(url)).to be false
+    end
+
+    it "should fail if 'build_flavor' is not present and tagline is correct" do
+      allow(adapter).to receive(:perform_request)
+                                .with(anything, :get, "/", anything, anything)
+                                .and_return(MockResponse.new(200, {"version": {"number": "7.5.0"}, "tagline": "You Know, for Search"}))
+      expect(subject.elasticsearch?(url)).to be false
+    end
+  end
+
+  context "when connecting to a cluster with version >= 7.14.0" do
+    it "should fail if 'X-elastic-product' header is not present" do
+      allow(adapter).to receive(:perform_request)
+                    .with(anything, :get, "/", anything, anything)
+                    .and_return(MockResponse.new(200, {"version": {"number": "7.14.0"}}))
+      expect(subject.elasticsearch?(url)).to be false
+    end
+
+    it "should fail if 'X-elastic-product' header is present but with bad value" do
+      allow(adapter).to receive(:perform_request)
+                    .with(anything, :get, "/", anything, anything)
+                    .and_return(MockResponse.new(200, {"version": {"number": "7.14.0"}}, {'X-elastic-product' => 'not good'}))
+      expect(subject.elasticsearch?(url)).to be false
+    end
+
+    it "must be successful when 'X-elastic-product' header is present with 'Elasticsearch' value" do
+      allow(adapter).to receive(:perform_request)
+                    .with(anything, :get, "/", anything, anything)
+                    .and_return(MockResponse.new(200, {"version": {"number": "7.14.0"}}, {'X-elastic-product' => 'Elasticsearch'}))
+      expect(subject.elasticsearch?(url)).to be true
+    end
+  end
+end

spec/unit/outputs/elasticsearch_spec.rb

@@ -156,7 +156,7 @@
         include_examples("an authenticated config")
       end
 
-      context 'claud_auth also set' do
+      context 'cloud_auth also set' do
         let(:do_register) { false } # this is what we want to test, so we disable the before(:each) call
         let(:options) { { "user" => user, "password" => password, "cloud_auth" => "elastic:my-passwd-00" } }