package org.keycloak.models.cache.infinispan;
import org.infinispan.Cache;
import org.jboss.logging.Logger;
import org.keycloak.cluster.ClusterProvider;
import org.keycloak.models.cache.infinispan.events.InvalidationEvent;
import org.keycloak.models.KeycloakSession;
import org.keycloak.models.cache.infinispan.entities.Revisioned;
import java.util.Collection;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.TimeUnit;
import java.util.function.Predicate;
/**
*
* Some notes on how this works:
* This implementation manages optimistic locking and version checks itself. The reason is Infinispan just does behave
* the way we need it to. Not saying Infinispan is bad, just that we have specific caching requirements!
*
* This is an invalidation cache implementation and requires to caches:
* Cache 1 is an Invalidation Cache
* Cache 2 is a local-only revision number cache.
*
*
* Each node in the cluster maintains its own revision number cache for each entry in the main invalidation cache. This revision
* cache holds the version counter for each cached entity.
*
* Cache listeners do not receive a @CacheEntryInvalidated event if that node does not have an entry for that item. So, consider the following.
1. Node 1 gets current counter for user. There currently isn't one as this user isn't cached.
2. Node 1 reads user from DB
3. Node 2 updates user
4. Node 2 calls cache.remove(user). This does not result in an invalidation listener event to node 1!
5. node 1 checks version counter, checks pass. Stale entry is cached.
The issue is that Node 1 doesn't have an entry for the user, so it never receives an invalidation listener event from Node 2 thus it can't bump the version. So, when node 1 goes to cache the user it is stale as the version number was never bumped.
So how is this issue fixed? here is pseudo code:
1. Node 1 calls cacheManager.getCurrentRevision() to get the current local version counter of that User
2. Node 1 getCurrentRevision() pulls current counter for that user
3. Node 1 getCurrentRevision() adds a "invalidation.key.userid" to invalidation cache. Its just a marker. nothing else
4. Node 2 update user
5. Node 2 does a cache.remove(user) cache.remove(invalidation.key.userid)
6. Node 1 receives invalidation event for invalidation.key.userid. Bumps the version counter for that user
7. node 1 version check fails, it doesn't cache the user
*
* @author <a href="mailto:bill@burkecentral.com">Bill Burke</a>
* @version $Revision: 1 $
*/
public abstract class CacheManager {
protected final Cache<String, Long> revisions;
protected final Cache<String, Revisioned> cache;
protected final UpdateCounter counter = new UpdateCounter();
public CacheManager(Cache<String, Revisioned> cache, Cache<String, Long> revisions) {
this.cache = cache;
this.revisions = revisions;
}
protected abstract Logger getLogger();
public Cache<String, Revisioned> getCache() {
return cache;
}
public long getCurrentCounter() {
return counter.current();
}
public Long getCurrentRevision(String id) {
Long revision = revisions.get(id);
if (revision == null) {
revision = counter.current();
}
return revision;
}
public void endRevisionBatch() {
try {
revisions.endBatch(true);
} catch (Exception e) {
}
}
public <T> T get(String id, Class<T> type) {
Revisioned o = (Revisioned)cache.get(id);
if (o == null) {
return null;
}
Long rev = revisions.get(id);
if (rev == null) {
if (getLogger().isTraceEnabled()) {
getLogger().tracev("get() missing rev {0}", id);
}
return null;
}
long oRev = o.getRevision() == null ? -1L : o.getRevision().longValue();
if (rev > oRev) {
if (getLogger().isTraceEnabled()) {
getLogger().tracev("get() rev: {0} o.rev: {1}", rev.longValue(), oRev);
}
return null;
}
return o != null && type.isInstance(o) ? type.cast(o) : null;
}
public Object invalidateObject(String id) {
Revisioned removed = (Revisioned)cache.remove(id);
if (getLogger().isTraceEnabled()) {
getLogger().tracef("Removed key='%s', value='%s' from cache", id, removed);
}
bumpVersion(id);
return removed;
}
protected void bumpVersion(String id) {
long next = counter.next();
Object rev = revisions.put(id, next);
}
public void addRevisioned(Revisioned object, long startupRevision) {
addRevisioned(object, startupRevision, -1);
}
public void addRevisioned(Revisioned object, long startupRevision, long lifespan) {
//startRevisionBatch();
String id = object.getId();
try {
//revisions.getAdvancedCache().lock(id);
Long rev = revisions.get(id);
if (rev == null) {
rev = counter.current();
revisions.put(id, rev);
}
revisions.startBatch();
if (!revisions.getAdvancedCache().lock(id)) {
if (getLogger().isTraceEnabled()) {
getLogger().tracev("Could not obtain version lock: {0}", id);
}
return;
}
rev = revisions.get(id);
if (rev == null) {
return;
}
if (rev > startupRevision) { // revision is ahead transaction start. Other transaction updated in the meantime. Don't cache
if (getLogger().isTraceEnabled()) {
getLogger().tracev("Skipped cache. Current revision {0}, Transaction start revision {1}", object.getRevision(), startupRevision);
}
return;
}
if (rev.equals(object.getRevision())) {
cache.putForExternalRead(id, object);
return;
}
if (rev > object.getRevision()) { // revision is ahead, don't cache
if (getLogger().isTraceEnabled()) getLogger().tracev("Skipped cache. Object revision {0}, Cache revision {1}", object.getRevision(), rev);
return;
}
// revisions cache has a lower value than the object.revision, so update revision and add it to cache
revisions.put(id, object.getRevision());
if (lifespan < 0) cache.putForExternalRead(id, object);
else cache.putForExternalRead(id, object, lifespan, TimeUnit.MILLISECONDS);
} finally {
endRevisionBatch();
}
}
public void clear() {
cache.clear();
revisions.clear();
}
public void addInvalidations(Predicate<Map.Entry<String, Revisioned>> predicate, Set<String> invalidations) {
Iterator<Map.Entry<String, Revisioned>> it = getEntryIterator(predicate);
while (it.hasNext()) {
invalidations.add(it.next().getKey());
}
}
private Iterator<Map.Entry<String, Revisioned>> getEntryIterator(Predicate<Map.Entry<String, Revisioned>> predicate) {
return cache
.entrySet()
.stream()
.filter(predicate).iterator();
}
public void sendInvalidationEvents(KeycloakSession session, Collection<InvalidationEvent> invalidationEvents) {
ClusterProvider clusterProvider = session.getProvider(ClusterProvider.class);
// Maybe add InvalidationEvent, which will be collection of all invalidationEvents? That will reduce cluster traffic even more.
for (InvalidationEvent event : invalidationEvents) {
clusterProvider.notify(generateEventId(event), event, true);
}
}
protected String generateEventId(InvalidationEvent event) {
return new StringBuilder(event.getId())
.append("_")
.append(event.hashCode())
.toString();
}
protected void invalidationEventReceived(InvalidationEvent event) {
Set<String> invalidations = new HashSet<>();
addInvalidationsFromEvent(event, invalidations);
getLogger().debugf("Invalidating %d cache items after received event %s", invalidations.size(), event);
for (String invalidation : invalidations) {
invalidateObject(invalidation);
}
}
protected abstract void addInvalidationsFromEvent(InvalidationEvent event, Set<String> invalidations);
}