Status
Current state: Under Discussion
Discussion thread: here
JIRA:
-
KAFKA-7277Getting issue details...
STATUS
Motivation
Right now Streams API unversally 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.
Public Interfaces
We need to add following method to public API.
Some of the old methods become deprecated. Other can be replaced, because they are not released, yet.
Method that proposed for replacement added in - KAFKA-7222Getting issue details... STATUS (KIP-328, commit b3771ba):
class Window { //Existing methods. Will be deprecated. Window(final long startMs, final long endMs) throws IllegalArgumentException; //New methods. Window(final Instant start, final Instant end) throws IllegalArgumentException; 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; long size(); //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); Map<Instant, Window> windowsForTime(final Instant timestamp); Duration windowSize(); } Materialized { //Existing method. Will be removed. Materialized<K, V, S> withRetention(final long retentionMs); //New method. Materialized<K, V, S> withRetention(final Duration retention); } 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); SessionWindows grace(final Duration afterWindowEnd); } TimeWindowedDeserializer { //Existing methods. Will be deprecated. TimeWindowedDeserializer(final Deserializer<T> inner, final long windowSizeMs); //New methods. TimeWindowedDeserializer(final Deserializer<T> inner, final Duration windowSize); Duration windowSize(); } TimeWindows { //Existing methods. Will be deprecated. static TimeWindows of(final long sizeMs) throws IllegalArgumentException; TimeWindows advanceBy(final long advanceMs); long size(); //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); Map<Instant, TimeWindow> windowsFor(final Instant timestamp); Duration windowSize(); TimeWindows grace(final Duration afterWindowEnd); } UnlimitedWindows { //Existing methods. Will be deprecated. UnlimitedWindows startOn(final long startMs) throws IllegalArgumentException; long size(); //Existing method. Will be removed. UnlimitedWindows grace(final long millisAfterWindowEnd); //New methods. UnlimitedWindows startOn(final Instant start) throws IllegalArgumentException; Map<Instant, UnlimitedWindow> windowsFor(final Instant timestamp); Duration windowSize(); UnlimitedWindows grace(final Duration afterWindowEnd); } 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); } ReadOnlyWindowStore<K, V> { //New methods. WindowStoreIterator<V> fetch(K key, Instant from, Duration duration); KeyValueIterator<Windowed<K>, V> fetch(K from, K to, Instant from, Duration duration); KeyValueIterator<Windowed<K>, V> fetchAll(Instant from, Duration duration); } SessionBytesStoreSupplier { //Existing methods. Will be deprecated. long segmentIntervalMs(); long retentionPeriod(); //New methods. Duration segmentInterval(); Duration retentionPeriodDuration(); } SessionStore { //New methods. KeyValueIterator<Windowed<K>, AGG> findSessions(final K key, Instant earliestSessionEnd, final Instant latestSessionStart); KeyValueIterator<Windowed<K>, AGG> findSessions(final K keyFrom, final K keyTo, Instant earliestSessionEnd, final Instant latestSessionStart); } Stores { //Existing methods. Will be deprecated. static WindowBytesStoreSupplier persistentWindowStore(final String name, final long retentionPeriodMs, final long windowSizeMs, final boolean retainDuplicates); static WindowBytesStoreSupplier persistentWindowStore(final String name, final long retentionPeriodMs, final long windowSizeMs, final boolean retainDuplicates, final long segmentIntervalMs); static SessionBytesStoreSupplier persistentSessionStore(final String name, final long retentionPeriodMs); //New methods. static WindowBytesStoreSupplier persistentWindowStore(final String name, final Duration retentionPeriod, final Duration windowSize, final boolean retainDuplicates); static WindowBytesStoreSupplier persistentWindowStore(final String name, final Duration retentionPeriod, final Duration windowSize, final boolean retainDuplicates, final Duration segmentInterval); static SessionBytesStoreSupplier persistentSessionStore(final String name, final Duration retentionPeriod); } WindowBytesStoreSupplier { //Existing methods. Will be deprecated. long segmentIntervalMs(); long windowSize(); long retentionPeriod(); //New methods. Duration segmentInterval(); Duration windowSizeDuration(); Duration retentionPeriodDuration(); } 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) }
Proposed Changes
New methods in public API are proposed. See "Public Interfaces" section.
For the methods that used both: internally and as a part of public API the proposal is:
- In this scope keep existing methods as is.
Try to reduce the visibility of methods in next tickets. - Introduce finer methods with
Instant
andDuration
Compatibility, Deprecation, and Migration Plan
No compatibility issues foreseen.
Rejected Alternatives
An alternative solution with long parameters is implemented right now.