ISSUE-2787:

1. Getting topic config defaults from server response
2. rm KafkaConstants
3. doc field added to TopicConfigDTO

kafka-ui-api/src/main/java/com/provectus/kafka/ui/model/InternalTopicConfig.java

@@ -1,8 +1,5 @@
 package com.provectus.kafka.ui.model;
 
-import static com.provectus.kafka.ui.util.KafkaConstants.TOPIC_DEFAULT_CONFIGS;
-import static org.apache.kafka.common.config.TopicConfig.MESSAGE_FORMAT_VERSION_CONFIG;
-
 import java.util.List;
 import lombok.Builder;
 import lombok.Data;
@@ -19,6 +16,7 @@ public class InternalTopicConfig {
   private final boolean isSensitive;
   private final boolean isReadOnly;
   private final List<ConfigEntry.ConfigSynonym> synonyms;
+  private final String doc;
 
   public static InternalTopicConfig from(ConfigEntry configEntry) {
     InternalTopicConfig.InternalTopicConfigBuilder builder = InternalTopicConfig.builder()
@@ -27,11 +25,22 @@ public class InternalTopicConfig {
         .source(configEntry.source())
         .isReadOnly(configEntry.isReadOnly())
         .isSensitive(configEntry.isSensitive())
-        .synonyms(configEntry.synonyms());
-    if (configEntry.name().equals(MESSAGE_FORMAT_VERSION_CONFIG)) {
+        .synonyms(configEntry.synonyms())
+        .doc(configEntry.documentation());
+
+    if (configEntry.source() == ConfigEntry.ConfigSource.DEFAULT_CONFIG) {
+      // this is important case, because for some configs like "confluent.*" no synonyms returned, but
+      // they are set by default and "source" == DEFAULT_CONFIG
       builder.defaultValue(configEntry.value());
     } else {
-      builder.defaultValue(TOPIC_DEFAULT_CONFIGS.get(configEntry.name()));
+      // normally by default first entity of synonyms values will be used.
+      configEntry.synonyms().stream()
+          // skipping DYNAMIC_TOPIC_CONFIG value - which is explicitly set value when
+          // topic was created (not default), see ConfigEntry.synonyms() doc
+          .filter(s -> s.source() != ConfigEntry.ConfigSource.DYNAMIC_TOPIC_CONFIG)
+          .map(ConfigEntry.ConfigSynonym::value)
+          .findFirst()
+          .ifPresent(builder::defaultValue);
     }
     return builder.build();
   }

kafka-ui-api/src/main/java/com/provectus/kafka/ui/service/ReactiveAdminClient.java

@@ -145,20 +145,20 @@ public class ReactiveAdminClient implements Closeable {
   }
 
   public Mono<Map<String, List<ConfigEntry>>> getTopicsConfig() {
-    return listTopics(true).flatMap(this::getTopicsConfig);
+    return listTopics(true).flatMap(topics -> getTopicsConfig(topics, false));
   }
 
-  public Mono<Map<String, List<ConfigEntry>>> getTopicsConfig(Collection<String> topicNames) {
+  public Mono<Map<String, List<ConfigEntry>>> getTopicsConfig(Collection<String> topicNames, boolean includeDoc) {
     // we need to partition calls, because it can lead to AdminClient timeouts in case of large topics count
     return partitionCalls(
         topicNames,
         200,
-        this::getTopicsConfigImpl,
+        part -> getTopicsConfigImpl(part, includeDoc),
         (m1, m2) -> ImmutableMap.<String, List<ConfigEntry>>builder().putAll(m1).putAll(m2).build()
     );
   }
 
-  private Mono<Map<String, List<ConfigEntry>>> getTopicsConfigImpl(Collection<String> topicNames) {
+  private Mono<Map<String, List<ConfigEntry>>> getTopicsConfigImpl(Collection<String> topicNames, boolean includeDoc) {
     List<ConfigResource> resources = topicNames.stream()
         .map(topicName -> new ConfigResource(ConfigResource.Type.TOPIC, topicName))
         .collect(toList());
@@ -166,7 +166,7 @@ public class ReactiveAdminClient implements Closeable {
     return toMonoWithExceptionFilter(
         client.describeConfigs(
             resources,
-            new DescribeConfigsOptions().includeSynonyms(true)).values(),
+            new DescribeConfigsOptions().includeSynonyms(true).includeDocumentation(includeDoc)).values(),
         UnknownTopicOrPartitionException.class
     ).map(config -> config.entrySet().stream()
         .collect(toMap(

kafka-ui-api/src/main/java/com/provectus/kafka/ui/service/TopicsService.java

@@ -68,7 +68,7 @@ public class TopicsService {
     }
     return adminClientService.get(c)
         .flatMap(ac ->
-            ac.describeTopics(topics).zipWith(ac.getTopicsConfig(topics),
+            ac.describeTopics(topics).zipWith(ac.getTopicsConfig(topics, false),
                 (descriptions, configs) -> {
                   statisticsCache.update(c, descriptions, configs);
                   return getPartitionOffsets(descriptions, ac).map(offsets -> {
@@ -160,7 +160,7 @@ public class TopicsService {
 
   public Mono<List<ConfigEntry>> getTopicConfigs(KafkaCluster cluster, String topicName) {
     return adminClientService.get(cluster)
-        .flatMap(ac -> ac.getTopicsConfig(List.of(topicName)))
+        .flatMap(ac -> ac.getTopicsConfig(List.of(topicName), true))
         .map(m -> m.values().stream().findFirst().orElseThrow(TopicNotFoundException::new));
   }
 

kafka-ui-api/src/main/java/com/provectus/kafka/ui/util/KafkaConstants.java

@@ -1,65 +0,0 @@
-package com.provectus.kafka.ui.util;
-
-import static org.apache.kafka.common.config.TopicConfig.CLEANUP_POLICY_CONFIG;
-import static org.apache.kafka.common.config.TopicConfig.CLEANUP_POLICY_DELETE;
-import static org.apache.kafka.common.config.TopicConfig.COMPRESSION_TYPE_CONFIG;
-import static org.apache.kafka.common.config.TopicConfig.DELETE_RETENTION_MS_CONFIG;
-import static org.apache.kafka.common.config.TopicConfig.FILE_DELETE_DELAY_MS_CONFIG;
-import static org.apache.kafka.common.config.TopicConfig.FLUSH_MESSAGES_INTERVAL_CONFIG;
-import static org.apache.kafka.common.config.TopicConfig.FLUSH_MS_CONFIG;
-import static org.apache.kafka.common.config.TopicConfig.INDEX_INTERVAL_BYTES_CONFIG;
-import static org.apache.kafka.common.config.TopicConfig.MAX_COMPACTION_LAG_MS_CONFIG;
-import static org.apache.kafka.common.config.TopicConfig.MAX_MESSAGE_BYTES_CONFIG;
-import static org.apache.kafka.common.config.TopicConfig.MESSAGE_DOWNCONVERSION_ENABLE_CONFIG;
-import static org.apache.kafka.common.config.TopicConfig.MESSAGE_TIMESTAMP_DIFFERENCE_MAX_MS_CONFIG;
-import static org.apache.kafka.common.config.TopicConfig.MESSAGE_TIMESTAMP_TYPE_CONFIG;
-import static org.apache.kafka.common.config.TopicConfig.MIN_CLEANABLE_DIRTY_RATIO_CONFIG;
-import static org.apache.kafka.common.config.TopicConfig.MIN_COMPACTION_LAG_MS_CONFIG;
-import static org.apache.kafka.common.config.TopicConfig.MIN_IN_SYNC_REPLICAS_CONFIG;
-import static org.apache.kafka.common.config.TopicConfig.PREALLOCATE_CONFIG;
-import static org.apache.kafka.common.config.TopicConfig.RETENTION_BYTES_CONFIG;
-import static org.apache.kafka.common.config.TopicConfig.RETENTION_MS_CONFIG;
-import static org.apache.kafka.common.config.TopicConfig.SEGMENT_BYTES_CONFIG;
-import static org.apache.kafka.common.config.TopicConfig.SEGMENT_INDEX_BYTES_CONFIG;
-import static org.apache.kafka.common.config.TopicConfig.SEGMENT_JITTER_MS_CONFIG;
-import static org.apache.kafka.common.config.TopicConfig.SEGMENT_MS_CONFIG;
-import static org.apache.kafka.common.config.TopicConfig.UNCLEAN_LEADER_ELECTION_ENABLE_CONFIG;
-
-import java.util.AbstractMap;
-import java.util.Map;
-
-public final class KafkaConstants {
-
-  private static final String LONG_MAX_STRING = Long.toString(Long.MAX_VALUE);
-
-  public static final Map<String, String> TOPIC_DEFAULT_CONFIGS = Map.ofEntries(
-      new AbstractMap.SimpleEntry<>(CLEANUP_POLICY_CONFIG, CLEANUP_POLICY_DELETE),
-      new AbstractMap.SimpleEntry<>(COMPRESSION_TYPE_CONFIG, "producer"),
-      new AbstractMap.SimpleEntry<>(DELETE_RETENTION_MS_CONFIG, "86400000"),
-      new AbstractMap.SimpleEntry<>(FILE_DELETE_DELAY_MS_CONFIG, "60000"),
-      new AbstractMap.SimpleEntry<>(FLUSH_MESSAGES_INTERVAL_CONFIG, LONG_MAX_STRING),
-      new AbstractMap.SimpleEntry<>(FLUSH_MS_CONFIG, LONG_MAX_STRING),
-      new AbstractMap.SimpleEntry<>("follower.replication.throttled.replicas", ""),
-      new AbstractMap.SimpleEntry<>(INDEX_INTERVAL_BYTES_CONFIG, "4096"),
-      new AbstractMap.SimpleEntry<>("leader.replication.throttled.replicas", ""),
-      new AbstractMap.SimpleEntry<>(MAX_COMPACTION_LAG_MS_CONFIG, LONG_MAX_STRING),
-      new AbstractMap.SimpleEntry<>(MAX_MESSAGE_BYTES_CONFIG, "1000012"),
-      new AbstractMap.SimpleEntry<>(MESSAGE_TIMESTAMP_DIFFERENCE_MAX_MS_CONFIG, LONG_MAX_STRING),
-      new AbstractMap.SimpleEntry<>(MESSAGE_TIMESTAMP_TYPE_CONFIG, "CreateTime"),
-      new AbstractMap.SimpleEntry<>(MIN_CLEANABLE_DIRTY_RATIO_CONFIG, "0.5"),
-      new AbstractMap.SimpleEntry<>(MIN_COMPACTION_LAG_MS_CONFIG, "0"),
-      new AbstractMap.SimpleEntry<>(MIN_IN_SYNC_REPLICAS_CONFIG, "1"),
-      new AbstractMap.SimpleEntry<>(PREALLOCATE_CONFIG, "false"),
-      new AbstractMap.SimpleEntry<>(RETENTION_BYTES_CONFIG, "-1"),
-      new AbstractMap.SimpleEntry<>(RETENTION_MS_CONFIG, "604800000"),
-      new AbstractMap.SimpleEntry<>(SEGMENT_BYTES_CONFIG, "1073741824"),
-      new AbstractMap.SimpleEntry<>(SEGMENT_INDEX_BYTES_CONFIG, "10485760"),
-      new AbstractMap.SimpleEntry<>(SEGMENT_JITTER_MS_CONFIG, "0"),
-      new AbstractMap.SimpleEntry<>(SEGMENT_MS_CONFIG, "604800000"),
-      new AbstractMap.SimpleEntry<>(UNCLEAN_LEADER_ELECTION_ENABLE_CONFIG, "false"),
-      new AbstractMap.SimpleEntry<>(MESSAGE_DOWNCONVERSION_ENABLE_CONFIG, "true")
-  );
-
-  private KafkaConstants() {
-  }
-}

kafka-ui-contract/src/main/resources/swagger/kafka-ui-api.yaml

@@ -2260,6 +2260,8 @@ components:
           type: array
           items:
             $ref: "#/components/schemas/ConfigSynonym"
+        doc:
+          type: string
       required:
         - name