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Discussion thread: here
JIRA:

Jira
serverASF JIRA
columnskey,summary,type,created,updated,due,assignee,reporter,priority,status,resolution
serverId5aa69414-a9e9-3523-82ec-879b028fb15b
keyKAFKA-7277
Jira
serverASF JIRA
columnskey,summary,type,created,updated,due,assignee,reporter,priority,status,resolution
serverId5aa69414-a9e9-3523-82ec-879b028fb15b
keyKAFKA-7477

Motivation

  1. KAFKA-7277:

    Right now Streams API universally represents time as ms-since-unix-epoch.
    There's nothing wrong, per se, with this, but Duration is more ergonomic for an API.
    What we don't want is to present a heterogeneous API, so we need to make sure the whole Streams API is in terms of Duration.

  2. KAFKA-7477:
    Improve of semantics of KafkaStreams#close(Duration)

Public Interfaces

We need to add following method to public API.

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Code Block
languagejava
firstline0
titlePublic API changes
class Window {
	//New methods.
	Instant startTime();
	Instant endTime();
}

JoinWindows {
    //Existing methods. Will be deprecated.
    static JoinWindows of(final long timeDifferenceMs) throws IllegalArgumentException;
    JoinWindows before(final long timeDifferenceMs) throws IllegalArgumentException;
    JoinWindows after(final long timeDifferenceMs) throws IllegalArgumentException;	

	//Existing method. Will be removed.
	JoinWindows grace(final long millisAfterWindowEnd);

    //New methods.
    static JoinWindows of(final Duration timeDifference) throws IllegalArgumentException;
    JoinWindows before(final Duration timeDifference) throws IllegalArgumentException;
    JoinWindows after(final Duration timeDifference) throws IllegalArgumentException;
	JoinWindows grace(final Duration afterWindowEnd) throws IllegalArgumentException;
}

Materialized {
	//Existing method. Will be removed.
	Materialized<K, V, S> withRetention(final long retentionMs);

	//New method.
	Materialized<K, V, S> withRetention(final Duration retention) throws IllegalArgumentException;
}

SessionWindows {
	//Existing methods. Will be deprecated.
    static SessionWindows with(final long inactivityGapMs);

	//Existing methods. Will be removed.
	SessionWindows grace(final long millisAfterWindowEnd);

	//New methods.
    static SessionWindows with(final Duration inactivityGap) throws IllegalArgumentException;
	SessionWindows grace(final Duration afterWindowEnd) throws IllegalArgumentException;
}

TimeWindows {
	//Existing methods. Will be deprecated.
	static TimeWindows of(final long sizeMs) throws IllegalArgumentException;
	TimeWindows advanceBy(final long advanceMs);

	//Existing method. Will be removed.
	TimeWindows grace(final long millisAfterWindowEnd);

	//New methods.
	static TimeWindows of(final Duration size) throws IllegalArgumentException;
	TimeWindows advanceBy(final Duration advance);
	TimeWindows grace(final Duration afterWindowEnd);
}

UnlimitedWindows {
	//Existing methods. Will be deprecated.
    UnlimitedWindows startOn(final long startMs) throws IllegalArgumentException;

	//New methods.
    UnlimitedWindows startOn(final Instant start) throws IllegalArgumentException;
}

ProcessorContext {
    //Existing method. Will be deprecated.
    Cancellable schedule(final long intervalMs,
                         final PunctuationType type,
                         final Punctuator callback);

	//New method.
    Cancellable schedule(final Duration interval,
                         final PunctuationType type,
                         final Punctuator callback) throws IllegalArgumentException;
}

ReadOnlyWindowStore<K, V> {
    //Deprecated methods.
    WindowStoreIterator<V> fetch(K key, long timeFrom, long timeTo);
    KeyValueIterator<Windowed<K>, V> fetch(K from, K to, long timeFrom, long timeTo);
    KeyValueIterator<Windowed<K>, V> fetchAll(long timeFrom, long timeTo);

	//New methods.
	//This changed after initial KIP voting based on [PR discussion](https://github.com/apache/kafka/pull/5682#discussion_r222494244)
    WindowStoreIterator<V> fetch(K key, Instant from, DurationInstant durationto) throws IllegalArgumentException;
    KeyValueIterator<Windowed<K>, V> fetch(K from, K to, Instant from, DurationInstant durationto) throws IllegalArgumentException;
    KeyValueIterator<Windowed<K>, V> fetchAll(Instant from, DurationInstant durationto) throws IllegalArgumentException;
}

WindowStore {
	//New methods with default implementation that checks arguments and pass it to existing fetch methods.
    WindowStoreIterator<V> fetch(K key, long timeFrom, long timeTo) throws IllegalArgumentException;
    KeyValueIterator<Windowed<K>, V> fetch(K from, K to, long timeFrom, long timeTo) throws IllegalArgumentException;
    KeyValueIterator<Windowed<K>, V> fetchAll(long timeFrom, long timeTo) throws IllegalArgumentException;
}

Stores {
	//Existing methods. Will be deprecated.
	static WindowBytesStoreSupplier persistentWindowStore(final String name,
    	                                                  final long retentionPeriodMs,
        	                                              final long windowSizeMs,
                                                          final boolean retainDuplicates);


	//This method added after KIP voting. Based on John Roesler comment(https://github.com/apache/kafka/pull/5682#discussion_r221472187)
	static SessionBytesStoreSupplier persistentSessionStore(final String name,
                                                               final long retentionPeriod);

	static WindowBytesStoreSupplier persistentWindowStore(final String name,
                                                          final long retentionPeriodMs,
                                                          final long windowSizeMs,
                                                          final boolean retainDuplicates,
                                                          final long segmentIntervalMs);

	//New methods.
	static WindowBytesStoreSupplier persistentWindowStore(final String name,
    	                                                  final Duration retentionPeriod,
        	                                              final Duration windowSize,
                                                          final boolean retainDuplicates) throws IllegalArgumentException;

	static SessionBytesStoreSupplier persistentSessionStore(final String name,
                                                            final Duration retentionPeriod) throws IllegalArgumentException;
}

KafkaStreams {
	//Existing method. Will be deprecated.
	public synchronized boolean close(final long timeout, final TimeUnit timeUnit);

	//New method
	public synchronized boolean close(final Duration timeout) throws IllegalArgumentException;
}

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  1. In this scope keep existing methods as is.
    Try to reduce the visibility of methods in next tickets.
  2. Introduce finer methods with Instant and Duration

Changes in KafkaStream#close semantics:

  1. reject negative numbers
  2. make 0 just signal and return immediately (after checking the state once)

Default implementation of fetch methods in WindowStore.

Compatibility, Deprecation, and Migration Plan

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