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Backport of InMemoryWebSession changes

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- hooks to check expired sessions in both create and retrieve.
- maxSessions limit on the total number of sessions.
- getSessions method for management purposes
- removeExpiredSessions public API

Issue: SPR-17020, SPR-16713
This commit is contained in:
Rossen Stoyanchev
2018-07-12 16:27:42 -04:00
parent 7ea8ecb6ab
commit 6218db9831
2 changed files with 151 additions and 82 deletions
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155
spring-web/src/main/java/org/springframework/web/server/session/InMemoryWebSessionStore.java
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@@ -20,10 +20,11 @@ import java.time.Clock;
import java.time.Duration;
import java.time.Instant;
import java.time.ZoneId;
import java.time.temporal.ChronoUnit;
import java.util.Collections;
import java.util.Iterator;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.atomic.AtomicReference;
import java.util.concurrent.locks.ReentrantLock;
@@ -43,20 +44,37 @@ import org.springframework.web.server.WebSession;
*/
public class InMemoryWebSessionStore implements WebSessionStore {
/** Minimum period between expiration checks */
private static final Duration EXPIRATION_CHECK_PERIOD = Duration.ofSeconds(60);
private static final IdGenerator idGenerator = new JdkIdGenerator();
private int maxSessions = 10000;
private Clock clock = Clock.system(ZoneId.of("GMT"));
private final ConcurrentMap<String, InMemoryWebSession> sessions = new ConcurrentHashMap<>();
private final Map<String, InMemoryWebSession> sessions = new ConcurrentHashMap<>();
private volatile Instant nextExpirationCheckTime = Instant.now(this.clock).plus(EXPIRATION_CHECK_PERIOD);
private final ExpiredSessionChecker expiredSessionChecker = new ExpiredSessionChecker();
private final ReentrantLock expirationCheckLock = new ReentrantLock();
/**
* Set the maximum number of sessions that can be stored. Once the limit is
* reached, any attempt to store an additional session will result in an
* {@link IllegalStateException}.
* <p>By default set to 10000.
* @param maxSessions the maximum number of sessions
* @since 5.1
*/
public void setMaxSessions(int maxSessions) {
this.maxSessions = maxSessions;
}
/**
* Return the maximum number of sessions that can be stored.
* @since 5.1
*/
public int getMaxSessions() {
return this.maxSessions;
}
/**
* Configure the {@link Clock} to use to set lastAccessTime on every created
@@ -70,8 +88,7 @@ public class InMemoryWebSessionStore implements WebSessionStore {
public void setClock(Clock clock) {
Assert.notNull(clock, "Clock is required");
this.clock = clock;
// Force a check when clock changes..
this.nextExpirationCheckTime = Instant.now(this.clock);
removeExpiredSessions();
}
/**
@@ -81,67 +98,67 @@ public class InMemoryWebSessionStore implements WebSessionStore {
return this.clock;
}
/**
* Return the map of sessions with an {@link Collections#unmodifiableMap
* unmodifiable} wrapper. This could be used for management purposes, to
* list active sessions, invalidate expired ones, etc.
* @since 5.1
*/
public Map<String, InMemoryWebSession> getSessions() {
return Collections.unmodifiableMap(this.sessions);
}
@Override
public Mono<WebSession> createWebSession() {
return Mono.fromSupplier(InMemoryWebSession::new);
Instant now = this.clock.instant();
this.expiredSessionChecker.checkIfNecessary(now);
return Mono.fromSupplier(() -> new InMemoryWebSession(now));
}
@Override
public Mono<WebSession> retrieveSession(String id) {
Instant currentTime = Instant.now(this.clock);
if (!this.sessions.isEmpty() && !currentTime.isBefore(this.nextExpirationCheckTime)) {
checkExpiredSessions(currentTime);
}
Instant now = this.clock.instant();
this.expiredSessionChecker.checkIfNecessary(now);
InMemoryWebSession session = this.sessions.get(id);
if (session == null) {
return Mono.empty();
}
else if (session.isExpired(currentTime)) {
else if (session.isExpired(now)) {
this.sessions.remove(id);
return Mono.empty();
}
else {
session.updateLastAccessTime(currentTime);
session.updateLastAccessTime(now);
return Mono.just(session);
}
}
private void checkExpiredSessions(Instant currentTime) {
if (this.expirationCheckLock.tryLock()) {
try {
Iterator<InMemoryWebSession> iterator = this.sessions.values().iterator();
while (iterator.hasNext()) {
InMemoryWebSession session = iterator.next();
if (session.isExpired(currentTime)) {
iterator.remove();
session.invalidate();
}
}
}
finally {
this.nextExpirationCheckTime = currentTime.plus(EXPIRATION_CHECK_PERIOD);
this.expirationCheckLock.unlock();
}
}
}
@Override
public Mono<Void> removeSession(String id) {
this.sessions.remove(id);
return Mono.empty();
}
public Mono<WebSession> updateLastAccessTime(WebSession webSession) {
public Mono<WebSession> updateLastAccessTime(WebSession session) {
return Mono.fromSupplier(() -> {
Assert.isInstanceOf(InMemoryWebSession.class, webSession);
InMemoryWebSession session = (InMemoryWebSession) webSession;
session.updateLastAccessTime(Instant.now(getClock()));
Assert.isInstanceOf(InMemoryWebSession.class, session);
((InMemoryWebSession) session).updateLastAccessTime(this.clock.instant());
return session;
});
}
/**
* Check for expired sessions and remove them. Typically such checks are
* kicked off lazily during calls to {@link #createWebSession() create} or
* {@link #retrieveSession retrieve}, no less than 60 seconds apart.
* This method can be called to force a check at a specific time.
* @since 5.1
*/
public void removeExpiredSessions() {
this.expiredSessionChecker.removeExpiredSessions(this.clock.instant());
}
private class InMemoryWebSession implements WebSession {
@@ -157,8 +174,9 @@ public class InMemoryWebSessionStore implements WebSessionStore {
private final AtomicReference<State> state = new AtomicReference<>(State.NEW);
public InMemoryWebSession() {
this.creationTime = Instant.now(getClock());
public InMemoryWebSession(Instant creationTime) {
this.creationTime = creationTime;
this.lastAccessTime = this.creationTime;
}
@@ -222,6 +240,12 @@ public class InMemoryWebSessionStore implements WebSessionStore {
@Override
public Mono<Void> save() {
if (sessions.size() >= maxSessions) {
expiredSessionChecker.removeExpiredSessions(clock.instant());
if (sessions.size() >= maxSessions) {
return Mono.error(new IllegalStateException("Max sessions limit reached: " + sessions.size()));
}
}
if (!getAttributes().isEmpty()) {
this.state.compareAndSet(State.NEW, State.STARTED);
}
@@ -231,14 +255,14 @@ public class InMemoryWebSessionStore implements WebSessionStore {
@Override
public boolean isExpired() {
return isExpired(Instant.now(getClock()));
return isExpired(clock.instant());
}
private boolean isExpired(Instant currentTime) {
private boolean isExpired(Instant now) {
if (this.state.get().equals(State.EXPIRED)) {
return true;
}
if (checkExpired(currentTime)) {
if (checkExpired(now)) {
this.state.set(State.EXPIRED);
return true;
}
@@ -256,6 +280,47 @@ public class InMemoryWebSessionStore implements WebSessionStore {
}
private class ExpiredSessionChecker {
/** Max time between expiration checks. */
private static final int CHECK_PERIOD = 60 * 1000;
private final ReentrantLock lock = new ReentrantLock();
private Instant checkTime = clock.instant().plus(CHECK_PERIOD, ChronoUnit.MILLIS);
public void checkIfNecessary(Instant now) {
if (this.checkTime.isBefore(now)) {
removeExpiredSessions(now);
}
}
public void removeExpiredSessions(Instant now) {
if (sessions.isEmpty()) {
return;
}
if (this.lock.tryLock()) {
try {
Iterator<InMemoryWebSession> iterator = sessions.values().iterator();
while (iterator.hasNext()) {
InMemoryWebSession session = iterator.next();
if (session.isExpired(now)) {
iterator.remove();
session.invalidate();
}
}
}
finally {
this.checkTime = now.plus(CHECK_PERIOD, ChronoUnit.MILLIS);
this.lock.unlock();
}
}
}
}
private enum State { NEW, STARTED, EXPIRED }
}