Inform the user if target option is not defined in local_lookups definitions when ECS is enabled (#71)

Configuration of `logstash-filter-jdbc_static` filter definition requires also the definition of `local_lookups` sections. 
Those sections has an optional `target` field to specify the Event's field name where to put the loaded columns, if
the plugin is used in with ECS enabled and any blocks doesn't define explicitly a target, then a informative line is printed out to the user.

Co-authored-by: Karol Bucek <[email protected]>

Author: andsel

CHANGELOG.md

@@ -2,6 +2,9 @@
   - Added `target` option to JDBC input, allowing the row columns to target a specific field instead of being expanded 
     at the root of the event. This allows the input to play nicer with the Elastic Common Schema when 
     the input does not follow the schema. [#69](https://github.com/logstash-plugins/logstash-integration-jdbc/issues/69)
+    
+  - Added `target` to JDBC filter static `local_lookups` to verify it's properly valued when ECS is enabled. 
+    [#71](https://github.com/logstash-plugins/logstash-integration-jdbc/issues/71)
 
 ## 5.0.7
   - Feat: try hard to log Java cause (chain) [#62](https://github.com/logstash-plugins/logstash-integration-jdbc/pull/62)

lib/logstash/filters/jdbc/lookup.rb

@@ -56,6 +56,12 @@ def initialize(options, globals, default_id)
       @target = options["target"]
       @id_used_as_target = @target.nil?
       if @id_used_as_target
+        # target shouldn't be nil if ecs_compatibility is not :disabled
+        if globals[:ecs_compatibility] != :disabled
+          logger.info('ECS compatibility is enabled but no ``target`` option was specified, it is recommended'\
+                            ' to set the option to avoid potential schema conflicts (if your data is ECS compliant or'\
+                            ' non-conflicting feel free to ignore this message)')
+        end
         @target = @id
       end
       @options = options

lib/logstash/filters/jdbc_static.rb

@@ -2,6 +2,7 @@
 require "logstash-integration-jdbc_jars"
 require "logstash/filters/base"
 require "logstash/namespace"
+require "logstash/plugin_mixins/ecs_compatibility_support"
 require_relative "jdbc/loader"
 require_relative "jdbc/loader_schedule"
 require_relative "jdbc/repeating_load_runner"
@@ -14,6 +15,9 @@
 
 #
 module LogStash module Filters class JdbcStatic < LogStash::Filters::Base
+  # adds ecs_compatibility config which could be :disabled or :v1
+  include LogStash::PluginMixins::ECSCompatibilitySupport(:disabled, :v1, :v8 => :v1)
+
   config_name "jdbc_static"
 
   # Define the loaders, an Array of Hashes, to fetch remote data and create local tables.
@@ -214,6 +218,7 @@ def global_lookup_options(options = Hash.new)
     options["lookup_jdbc_driver_class"] = @lookup_jdbc_driver_class
     options["lookup_jdbc_driver_library"] = @lookup_jdbc_driver_library
     options["lookup_jdbc_connection_string"] = @lookup_jdbc_connection_string
+    options["ecs_compatibility"] = ecs_compatibility
     options
   end
 

spec/filters/jdbc/lookup_spec.rb

@@ -248,6 +248,37 @@ module LogStash module Filters module Jdbc
         expect(subject.valid?).to be_falsey
       end
     end
+
+    describe "validation of target option" do
+      let(:lookup_hash) do
+        {
+          "query" => "select * from servers WHERE ip LIKE ? AND os LIKE ?",
+          "prepared_parameters" => ["%%{[ip]}"],
+        }
+      end
+
+      it "should log a warn when ECS is enabled and target not defined" do
+
+        class LoggableLookup < Lookup
+
+          @@TEST_LOGGER = nil
+
+          def self.logger=(log)
+            @@TEST_LOGGER = log
+          end
+
+          def self.logger
+            @@TEST_LOGGER
+          end
+        end
+
+        spy_logger = double("logger")
+        expect(spy_logger).to receive(:info).once.with(/ECS compatibility is enabled but no .*?target.*? was specified/)
+        LoggableLookup.logger = spy_logger
+
+        LoggableLookup.new(lookup_hash, {:ecs_compatibility => 'v1'}, "lookup-1")
+      end
+    end
   end
 end end end