com.yammer.dropwizard.auth.CachingAuthenticator Maven / Gradle / Ivy
package com.yammer.dropwizard.auth;
import com.google.common.base.Optional;
import com.google.common.cache.*;
import com.yammer.metrics.Metrics;
import com.yammer.metrics.core.Meter;
import com.yammer.metrics.core.Timer;
import com.yammer.metrics.core.TimerContext;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;
/**
* An {@link Authenticator} decorator which uses a Guava cache to temporarily cache credentials and
* their corresponding principals.
*
* @param the type of credentials the authenticator can authenticate
* @param the type of principals the authenticator returns
*/
public class CachingAuthenticator implements Authenticator {
/**
* Wraps an underlying authenticator with a cache.
*
* @param authenticator the underlying authenticator
* @param cacheSpec a {@link CacheBuilderSpec}
* @param the type of credentials the authenticator can authenticate
* @param the type of principals the authenticator returns
* @return a cached version of {@code authenticator}
*/
public static CachingAuthenticator wrap(Authenticator authenticator,
CacheBuilderSpec cacheSpec) {
return new CachingAuthenticator(authenticator, CacheBuilder.from(cacheSpec));
}
private final Authenticator underlying;
private final LoadingCache> cache;
private final Meter cacheMisses;
private final Timer gets;
private CachingAuthenticator(Authenticator authenticator,
CacheBuilder builder) {
this.underlying = authenticator;
this.cacheMisses = Metrics.newMeter(authenticator.getClass(),
"cache-misses",
"lookups",
TimeUnit.SECONDS);
this.gets = Metrics.newTimer(authenticator.getClass(),
"gets",
TimeUnit.MILLISECONDS,
TimeUnit.SECONDS);
this.cache = builder.recordStats().build(new CacheLoader> () {
@Override
public Optional load(C key) throws Exception {
cacheMisses.mark();
return underlying.authenticate(key);
}
});
}
@Override
public Optional
authenticate(C credentials) throws AuthenticationException {
final TimerContext context = gets.time();
try {
return cache.get(credentials);
} catch (ExecutionException e) {
throw new AuthenticationException(e);
} finally {
context.stop();
}
}
/**
* Discards any cached principal for the given credentials.
*
* @param credentials a set of credentials
*/
public void invalidate(C credentials) {
cache.invalidate(credentials);
}
/**
* Discards any cached principal for the given collection of credentials.
*
* @param credentials a collection of credentials
*/
public void invalidateAll(Iterable credentials) {
cache.invalidateAll(credentials);
}
/**
* Discards all cached principals.
*/
public void invalidateAll() {
cache.invalidateAll();
}
/**
* Returns the number of cached principals.
*
* @return the number of cached principals
*/
public long size() {
return cache.size();
}
/**
* Returns a set of statistics about the cache contents and usage.
*
* @return a set of statistics about the cache contents and usage
*/
public CacheStats stats() {
return cache.stats();
}
}