* terms of the Eclipse Public License v1.0 which accompanies this distribution,
* and is available at http://www.eclipse.org/legal/epl-v10.html
*/
-
package org.opendaylight.controller.cluster.raft;
-import akka.japi.Procedure;
import java.util.List;
+import java.util.function.Consumer;
+import org.eclipse.jdt.annotation.NonNull;
+import org.eclipse.jdt.annotation.Nullable;
/**
- * Represents the ReplicatedLog that needs to be kept in sync by the RaftActor
+ * Represents the ReplicatedLog that needs to be kept in sync by the RaftActor.
*/
public interface ReplicatedLog {
+ long NO_MAX_SIZE = -1;
+
/**
- * Get a replicated log entry at the specified index
+ * Return the replicated log entry at the specified index.
*
* @param index the index of the log entry
- * @return the ReplicatedLogEntry at index. null if index less than 0 or
- * greater than the size of the in-memory journal.
+ * @return the ReplicatedLogEntry if found, otherwise null if the adjusted index less than 0 or
+ * greater than the size of the in-memory journal
*/
- ReplicatedLogEntry get(long index);
-
+ @Nullable ReplicatedLogEntry get(long index);
/**
- * Get the last replicated log entry
+ * Return the last replicated log entry in the log or null of not found.
*
- * @return
+ * @return the last replicated log entry in the log or null of not found.
*/
- ReplicatedLogEntry last();
+ @Nullable ReplicatedLogEntry last();
/**
+ * Return the index of the last entry in the log or -1 if the log is empty.
*
- * @return
+ * @return the index of the last entry in the log or -1 if the log is empty.
*/
long lastIndex();
/**
+ * Return the term of the last entry in the log or -1 if the log is empty.
*
- * @return
+ * @return the term of the last entry in the log or -1 if the log is empty.
*/
long lastTerm();
/**
- * To be called when we need to remove entries from the in-memory log.
- * This method will remove all entries >= index. This method should be used
- * during recovery to appropriately trim the log based on persisted
- * information
+ * Removes entries from the in-memory log starting at the given index.
*
- * @param index the index of the log entry
+ * @param index the index of the first log entry to remove
+ * @return the adjusted index of the first log entry removed or -1 if the log entry is not found.
*/
- void removeFrom(long index);
-
+ long removeFrom(long index);
/**
- * To be called when we need to remove entries from the in-memory log and we
- * need that information persisted to disk. This method will remove all
- * entries >= index.
+ * Removes entries from the in-memory log and the persisted log starting at the given index.
+ *
* <p>
* The persisted information would then be used during recovery to properly
* reconstruct the state of the in-memory replicated log
*
- * @param index the index of the log entry
+ * @param index the index of the first log entry to remove
+ * @return true if entries were removed, false otherwise
*/
- void removeFromAndPersist(long index);
+ boolean removeFromAndPersist(long index);
/**
- * Append an entry to the log
- * @param replicatedLogEntry
+ * Appends an entry to the log.
+ *
+ * @param replicatedLogEntry the entry to append
+ * @return true if the entry was successfully appended, false otherwise. An entry can fail to append if
+ * the index is already included in the log.
*/
- void append(ReplicatedLogEntry replicatedLogEntry);
+ boolean append(ReplicatedLogEntry replicatedLogEntry);
/**
* Optimization method to increase the capacity of the journal log prior to appending entries.
void increaseJournalLogCapacity(int amount);
/**
+ * Appends an entry to the in-memory log and persists it as well.
*
- * @param replicatedLogEntry
+ * @param replicatedLogEntry the entry to append
+ * @param callback the callback to be notified when persistence is complete (optional).
+ * @param doAsync if true, the persistent actor can receive subsequent messages to process in between the persist
+ * call and the execution of the associated callback. If false, subsequent messages are stashed and get
+ * delivered after persistence is complete and the associated callback is executed. In either case the
+ * callback is guaranteed to execute in the context of the actor associated with this log.
+ * @return true if the entry was successfully appended, false otherwise.
*/
- void appendAndPersist(final ReplicatedLogEntry replicatedLogEntry);
-
- void appendAndPersist(ReplicatedLogEntry replicatedLogEntry, Procedure<ReplicatedLogEntry> callback);
+ boolean appendAndPersist(@NonNull ReplicatedLogEntry replicatedLogEntry,
+ @Nullable Consumer<ReplicatedLogEntry> callback, boolean doAsync);
/**
+ * Returns a list of log entries starting from the given index to the end of the log.
*
- * @param index the index of the log entry
+ * @param index the index of the first log entry to get.
+ * @return the List of entries
*/
- List<ReplicatedLogEntry> getFrom(long index);
+ @NonNull List<ReplicatedLogEntry> getFrom(long index);
/**
+ * Returns a list of log entries starting from the given index up to the given maximum of entries or
+ * the given maximum accumulated size, whichever comes first.
*
- * @param index the index of the log entry
+ * @param index the index of the first log entry to get
+ * @param maxEntries the maximum number of entries to get
+ * @param maxDataSize the maximum accumulated size of the log entries to get
+ * @return the List of entries meeting the criteria.
*/
- List<ReplicatedLogEntry> getFrom(long index, int max);
+ @NonNull List<ReplicatedLogEntry> getFrom(long index, int maxEntries, long maxDataSize);
/**
+ * Returns the number of entries in the journal.
*
- * @return
+ * @return the number of entries
*/
long size();
/**
- * Checks if the entry at the specified index is present or not
+ * Checks if the entry at the specified index is present or not.
*
* @param index the index of the log entry
* @return true if the entry is present in the in-memory journal
boolean isPresent(long index);
/**
- * Checks if the entry is present in a snapshot
+ * Checks if the entry is present in a snapshot.
*
* @param index the index of the log entry
- * @return true if the entry is in the snapshot. false if the entry is not
- * in the snapshot even if the entry may be present in the replicated log
+ * @return true if the entry is in the snapshot. false if the entry is not in the snapshot even if the entry may
+ * be present in the replicated log
*/
boolean isInSnapshot(long index);
/**
- * Get the index of the snapshot
+ * Returns the index of the snapshot.
*
* @return the index from which the snapshot was created. -1 otherwise.
*/
long getSnapshotIndex();
/**
- * Get the term of the snapshot
+ * Returns the term of the snapshot.
*
- * @return the term of the index from which the snapshot was created. -1
- * otherwise
+ * @return the term of the index from which the snapshot was created. -1 otherwise
*/
long getSnapshotTerm();
/**
- * sets the snapshot index in the replicated log
- * @param snapshotIndex
+ * Sets the snapshot index in the replicated log.
+ *
+ * @param snapshotIndex the index to set
*/
void setSnapshotIndex(long snapshotIndex);
/**
- * sets snapshot term
- * @param snapshotTerm
+ * Sets snapshot term.
+ *
+ * @param snapshotTerm the term to set
*/
void setSnapshotTerm(long snapshotTerm);
/**
- * Clears the journal entries with startIndex(inclusive) and endIndex (exclusive)
- * @param startIndex
- * @param endIndex
+ * Clears the journal entries with startIndex (inclusive) and endIndex (exclusive).
+ *
+ * @param startIndex the start index (inclusive)
+ * @param endIndex the end index (exclusive)
*/
void clear(int startIndex, int endIndex);
/**
- * Handles all the bookkeeping in order to perform a rollback in the
- * event of SaveSnapshotFailure
- * @param snapshotCapturedIndex
- * @param snapshotCapturedTerm
+ * Handles all the bookkeeping in order to perform a rollback in the event of SaveSnapshotFailure.
+ *
+ * @param snapshotCapturedIndex the new snapshot index
+ * @param snapshotCapturedTerm the new snapshot term
*/
void snapshotPreCommit(long snapshotCapturedIndex, long snapshotCapturedTerm);
/**
- * Sets the Replicated log to state after snapshot success.
+ * Sets the Replicated log to state after snapshot success. This method is equivalent to
+ * {@code snapshotCommit(true)}.
*/
- void snapshotCommit();
+ default void snapshotCommit() {
+ snapshotCommit(true);
+ }
/**
- * Restores the replicated log to a state in the event of a save snapshot failure
+ * Sets the Replicated log to state after snapshot success. Most users will want to use {@link #snapshotCommit()}
+ * instead.
+ *
+ * @param updateDataSize true if {@link #dataSize()} should also be updated
+ */
+ void snapshotCommit(boolean updateDataSize);
+
+ /**
+ * Restores the replicated log to a state in the event of a save snapshot failure.
*/
void snapshotRollback();
/**
- * Size of the data in the log (in bytes)
+ * Returns the size of the data in the log (in bytes).
+ *
+ * @return the size of the data in the log (in bytes)
*/
int dataSize();
+ /**
+ * Determines if a snapshot needs to be captured based on the count/memory consumed and initiates the capture.
+ *
+ * @param replicatedLogEntry the last log entry.
+ */
+ void captureSnapshotIfReady(ReplicatedLogEntry replicatedLogEntry);
+
+ /**
+ * Determines if a snapshot should be captured based on the count/memory consumed.
+ *
+ * @param logIndex the log index to use to determine if the log count has exceeded the threshold
+ * @return true if a snapshot should be captured, false otherwise
+ */
+ boolean shouldCaptureSnapshot(long logIndex);
}
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