Feat: try hard to log Java cause (chain) (#62)

Author: kares

CHANGELOG.md

@@ -1,4 +1,8 @@
-## 5.y.z
+## 5.0.7
+  - Feat: try hard to log Java cause (chain) [#62](https://github.com/logstash-plugins/logstash-integration-jdbc/pull/62)
+
+    This allows seeing a full trace from the JDBC driver in case of connection errors. 
+
   - Refactored Lookup used in jdbc_streaming and jdbc_static to avoid code duplication. [#59](https://github.com/logstash-plugins/logstash-integration-jdbc/pull/59)
 
 ## 5.0.6

lib/logstash/plugin_mixins/jdbc/jdbc.rb

@@ -122,16 +122,32 @@ def jdbc_connect
         # rescue Java::JavaSql::SQLException, ::Sequel::Error => e
         rescue ::Sequel::Error => e
           if retry_attempts <= 0
-            @logger.error("Unable to connect to database. Tried #{@connection_retry_attempts} times", :error_message => e.message)
+            log_java_exception(e.cause)
+            @logger.error("Unable to connect to database. Tried #{@connection_retry_attempts} times", error_details(e, trace: true))
             raise e
           else
-            @logger.error("Unable to connect to database. Trying again", :error_message => e.message)
+            @logger.error("Unable to connect to database. Trying again", error_details(e, trace: false))
           end
         end
         sleep(@connection_retry_attempts_wait_time)
       end
     end
 
+    def error_details(e, trace: false)
+      details = { :message => e.message, :exception => e.class }
+      details[:cause] = e.cause if e.cause
+      details[:backtrace] = e.backtrace if trace || @logger.debug?
+      details
+    end
+
+    def log_java_exception(e)
+      return unless e.is_a?(java.lang.Exception)
+      # @logger.name using the same convention as LS does
+      logger = self.class.name.gsub('::', '.').downcase
+      logger = org.apache.logging.log4j.LogManager.getLogger(logger)
+      logger.error('', e) # prints nested causes
+    end
+
     def open_jdbc_connection
       # at this point driver is already loaded
       Sequel.application_timezone = @plugin_timezone.to_sym

logstash-integration-jdbc.gemspec

@@ -1,6 +1,6 @@
 Gem::Specification.new do |s|
   s.name = 'logstash-integration-jdbc'
-  s.version         = '5.0.6'
+  s.version         = '5.0.7'
   s.licenses = ['Apache License (2.0)']
   s.summary         = "Integration with JDBC - input and filter plugins"
   s.description     = "This gem is a Logstash plugin required to be installed on top of the Logstash core pipeline using $LS_HOME/bin/logstash-plugin install gemname. This gem is not a stand-alone program"

spec/inputs/integration/integ_spec.rb

@@ -68,6 +68,22 @@
 
     it "should not register correctly" do
       plugin.register
+      allow( plugin ).to receive(:log_java_exception)
+      q = Queue.new
+      expect do
+        plugin.run(q)
+      end.to raise_error(::Sequel::DatabaseConnectionError)
+    end
+
+    it "should log (native) Java driver error" do
+      plugin.register
+      expect( org.apache.logging.log4j.LogManager ).to receive(:getLogger).and_wrap_original do |m, *args|
+        logger = m.call(*args)
+        expect( logger ).to receive(:error) do |_, e|
+          expect( e ).to be_a org.postgresql.util.PSQLException
+        end.and_call_original
+        logger
+      end
       q = Queue.new
       expect do
         plugin.run(q)