ableegoldman commented on a change in pull request #10683:
URL: https://github.com/apache/kafka/pull/10683#discussion_r669210507
##########
File path:
streams/src/main/java/org/apache/kafka/streams/processor/internals/TopologyMetadata.java
##########
@@ -16,10 +16,294 @@
*/
package org.apache.kafka.streams.processor.internals;
+import org.apache.kafka.clients.consumer.OffsetResetStrategy;
+import org.apache.kafka.common.TopicPartition;
+import org.apache.kafka.streams.StreamsConfig;
+import org.apache.kafka.streams.errors.TopologyException;
+import org.apache.kafka.streams.processor.StateStore;
+import org.apache.kafka.streams.processor.TaskId;
+import
org.apache.kafka.streams.processor.internals.InternalTopologyBuilder.TopicsInfo;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
import java.util.Objects;
+import java.util.Set;
+import java.util.SortedMap;
+import java.util.TreeMap;
+import java.util.function.Consumer;
+import java.util.function.Function;
+import java.util.regex.Pattern;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+// TODO KAFKA-12648:
+// 1) synchronize on these methods instead of individual
InternalTopologyBuilder methods, where applicable
public class TopologyMetadata {
- //TODO KAFKA-12648: the TopologyMetadata class is filled in by Pt. 2 (PR
#10683)
+ private final Logger log = LoggerFactory.getLogger(TopologyMetadata.class);
+
+ // the '_' character is not allowed for topology names, thus it's safe to
use to indicate that it's not a named topology
+ private static final String UNNAMED_TOPOLOGY = "__UNNAMED_TOPOLOGY__";
+ private static final Pattern EMPTY_ZERO_LENGTH_PATTERN =
Pattern.compile("");
+
+ private final StreamsConfig config;
+ private final SortedMap<String, InternalTopologyBuilder> builders; // Keep
sorted by topology name for readability
+
+ private ProcessorTopology globalTopology;
+ private Map<String, StateStore> globalStateStores = new HashMap<>();
+ final Set<String> allInputTopics = new HashSet<>();
+
+ public TopologyMetadata(final InternalTopologyBuilder builder, final
StreamsConfig config) {
+ this.config = config;
+ builders = new TreeMap<>();
+ if (builder.hasNamedTopology()) {
+ builders.put(builder.namedTopology(), builder);
+ } else {
+ builders.put(UNNAMED_TOPOLOGY, builder);
+ }
+ }
+
+ public TopologyMetadata(final SortedMap<String, InternalTopologyBuilder>
builders, final StreamsConfig config) {
+ this.config = config;
+ this.builders = builders;
+ if (builders.isEmpty()) {
+ log.debug("Building KafkaStreams app with no empty topology");
+ }
+ }
+
+ public int getNumStreamThreads(final StreamsConfig config) {
+ final int configuredNumStreamThreads =
config.getInt(StreamsConfig.NUM_STREAM_THREADS_CONFIG);
+
+ // If the application uses named topologies, it's possible to start up
with no topologies at all and only add them later
+ if (builders.isEmpty()) {
+ if (configuredNumStreamThreads != 0) {
+ log.info("Overriding number of StreamThreads to zero for empty
topology");
+ }
+ return 0;
+ }
+
+ // If there are topologies but they are all empty, this indicates a
bug in user code
+ if (hasNoNonGlobalTopology() && !hasGlobalTopology()) {
Review comment:
Sure, but if `builders.isEmpty` then we would enter the `if` block above
and return before reaching this section of the code. But I think maybe you
meant that in `hasNoNonGlobalTopology`, we should actually return true only if
_all_ builders have no non-global topology, not if that's true for _any one_ of
them? There's some argument to be made for how to handle the case where some
named topologies are legit, while others are empty, but I would still advocate
for throwing an exception when _any_ topology is empty since this is not a
valid configuration. In which case, the current code is correct, but the
comment is not. I'll fix the misleading comment
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: jira-unsubscr...@kafka.apache.org
For queries about this service, please contact Infrastructure at:
us...@infra.apache.org
