MINOR: Add connector configs to site-docs

In AK's documentation, the config props for connectors are not listed (https://kafka.apache.org/documentation/#connectconfigs). This PR adds these sink and source connector configs to the html site-docs.

Signed-off-by: Arjun Satish <arjunconfluent.io>

Author: Arjun Satish <arjun@confluent.io>

Reviewers: Ewen Cheslack-Postava <ewen@confluent.io>

Closes #5469 from wicknicks/add-connector-configs-to-docs

build.gradle

@@ -709,6 +709,7 @@ project(':core') {
                                'genAdminClientConfigDocs', 'genProducerConfigDocs', 'genConsumerConfigDocs',
                                'genKafkaConfigDocs', 'genTopicConfigDocs',
                                ':connect:runtime:genConnectConfigDocs', ':connect:runtime:genConnectTransformationDocs',
+                               ':connect:runtime:genSinkConnectorConfigDocs', ':connect:runtime:genSourceConnectorConfigDocs',
                                ':streams:genStreamsConfigDocs', 'genConsumerMetricsDocs', 'genProducerMetricsDocs',
                                ':connect:runtime:genConnectMetricsDocs'], type: Tar) {
     classifier = 'site-docs'
@@ -1407,6 +1408,20 @@ project(':connect:runtime') {
     standardOutput = new File(generatedDocsDir, "connect_config.html").newOutputStream()
   }
 
+  task genSinkConnectorConfigDocs(type: JavaExec) {
+    classpath = sourceSets.main.runtimeClasspath
+    main = 'org.apache.kafka.connect.runtime.SinkConnectorConfig'
+    if( !generatedDocsDir.exists() ) { generatedDocsDir.mkdirs() }
+    standardOutput = new File(generatedDocsDir, "sink_connector_config.html").newOutputStream()
+  }
+
+  task genSourceConnectorConfigDocs(type: JavaExec) {
+    classpath = sourceSets.main.runtimeClasspath
+    main = 'org.apache.kafka.connect.runtime.SourceConnectorConfig'
+    if( !generatedDocsDir.exists() ) { generatedDocsDir.mkdirs() }
+    standardOutput = new File(generatedDocsDir, "source_connector_config.html").newOutputStream()
+  }
+
   task genConnectTransformationDocs(type: JavaExec) {
     classpath = sourceSets.main.runtimeClasspath
     main = 'org.apache.kafka.connect.tools.TransformationDoc'

clients/src/main/java/org/apache/kafka/common/config/ConfigDef.java

@@ -973,6 +973,19 @@ public class ConfigDef {
                 validator.ensureValid(name, value);
             }
         }
+
+        @Override
+        public String toString() {
+            if (validators == null) return "";
+            StringBuilder desc = new StringBuilder();
+            for (Validator v: validators) {
+                if (desc.length() > 0) {
+                    desc.append(',').append(' ');
+                }
+                desc.append(String.valueOf(v));
+            }
+            return desc.toString();
+        }
     }
 
     public static class NonEmptyString implements Validator {

connect/runtime/src/main/java/org/apache/kafka/connect/runtime/ConnectorConfig.java

@@ -169,6 +169,11 @@ public class ConnectorConfig extends AbstractConfig {
                             throw new ConfigException(name, value, "Duplicate alias provided.");
                         }
                     }
+
+                    @Override
+                    public String toString() {
+                        return "unique transformation aliases";
+                    }
                 }), Importance.LOW, TRANSFORMS_DOC, TRANSFORMS_GROUP, ++orderInGroup, Width.LONG, TRANSFORMS_DISPLAY)
                 .define(CONFIG_RELOAD_ACTION_CONFIG, Type.STRING, CONFIG_RELOAD_ACTION_RESTART,
                         in(CONFIG_RELOAD_ACTION_NONE, CONFIG_RELOAD_ACTION_RESTART), Importance.LOW,

connect/runtime/src/main/java/org/apache/kafka/connect/runtime/SinkConnectorConfig.java

@@ -119,4 +119,8 @@ public class SinkConnectorConfig extends ConnectorConfig {
     public boolean isDlqContextHeadersEnabled() {
         return getBoolean(DLQ_CONTEXT_HEADERS_ENABLE_CONFIG);
     }
+
+    public static void main(String[] args) {
+        System.out.println(config.toHtmlTable());
+    }
 }

connect/runtime/src/main/java/org/apache/kafka/connect/runtime/SourceConnectorConfig.java

@@ -32,4 +32,8 @@ public class SourceConnectorConfig extends ConnectorConfig {
     public SourceConnectorConfig(Plugins plugins, Map<String, String> props) {
         super(plugins, config, props);
     }
+
+    public static void main(String[] args) {
+        System.out.println(config.toHtmlTable());
+    }
 }

docs/configuration.html

@@ -440,6 +440,14 @@
   Below is the configuration of the Kafka Connect framework.
   <!--#include virtual="generated/connect_config.html" -->
 
+  <h4><a id="sourceconnectconfigs" href="#sourceconnectconfigs">3.5.1 Source Connector Configs</a></h4>
+  Below is the configuration of a source connector.
+  <!--#include virtual="generated/source_connector_config.html" -->
+
+  <h4><a id="sinkconnectconfigs" href="#sinkconnectconfigs">3.5.2 Sink Connector Configs</a></h4>
+  Below is the configuration of a sink connector.
+  <!--#include virtual="generated/sink_connector_config.html" -->
+
   <h3><a id="streamsconfigs" href="#streamsconfigs">3.6 Kafka Streams Configs</a></h3>
   Below is the configuration of the Kafka Streams client library.
   <!--#include virtual="generated/streams_config.html" -->