diff options
Diffstat (limited to 'infra/translate-utils/src/main/java/io/fd/honeycomb/translate/util/read/KeepaliveReaderWrapper.java')
-rw-r--r-- | infra/translate-utils/src/main/java/io/fd/honeycomb/translate/util/read/KeepaliveReaderWrapper.java | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/infra/translate-utils/src/main/java/io/fd/honeycomb/translate/util/read/KeepaliveReaderWrapper.java b/infra/translate-utils/src/main/java/io/fd/honeycomb/translate/util/read/KeepaliveReaderWrapper.java new file mode 100644 index 000000000..f8d1458c0 --- /dev/null +++ b/infra/translate-utils/src/main/java/io/fd/honeycomb/translate/util/read/KeepaliveReaderWrapper.java @@ -0,0 +1,173 @@ +/* + * Copyright (c) 2016 Cisco and/or its affiliates. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at: + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package io.fd.honeycomb.translate.util.read; + +import com.google.common.base.Optional; +import com.google.common.base.Preconditions; +import io.fd.honeycomb.translate.read.ReadContext; +import io.fd.honeycomb.translate.read.Reader; +import io.fd.honeycomb.translate.MappingContext; +import io.fd.honeycomb.translate.ModificationCache; +import io.fd.honeycomb.translate.read.ReadFailedException; +import java.io.Closeable; +import java.util.concurrent.ScheduledExecutorService; +import java.util.concurrent.ScheduledFuture; +import java.util.concurrent.TimeUnit; +import javax.annotation.Nonnegative; +import javax.annotation.Nonnull; +import org.opendaylight.yangtools.concepts.Builder; +import org.opendaylight.yangtools.yang.binding.DataObject; +import org.opendaylight.yangtools.yang.binding.InstanceIdentifier; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + * Reader wrapper that periodically invokes a read to determine whether reads are still fully functional. + * In case a specific error occurs, Keep-alive failure listener gets notified. + */ +public final class KeepaliveReaderWrapper<D extends DataObject, B extends Builder<D>> implements Reader<D, B>, Runnable, Closeable { + + private static final Logger LOG = LoggerFactory.getLogger(KeepaliveReaderWrapper.class); + + private static final NoopReadContext CTX = new NoopReadContext(); + + private final Reader<D, B> delegate; + private final Class<? extends Exception> exceptionType; + private final KeepaliveFailureListener failureListener; + private final ScheduledFuture<?> scheduledFuture; + + /** + * Create new Keepalive wrapper + * + * @param delegate underlying reader performing actual reads + * @param executor scheduled executor service to schedule keepalive calls + * @param exception type of exception used to differentiate keepalive exception from other exceptions + * @param delayInSeconds number of seconds to wait between keepalive calls + * @param failureListener listener to be called whenever a keepalive failure is detected + */ + public KeepaliveReaderWrapper(@Nonnull final Reader<D, B> delegate, + @Nonnull final ScheduledExecutorService executor, + @Nonnull final Class<? extends Exception> exception, + @Nonnegative final int delayInSeconds, + @Nonnull final KeepaliveFailureListener failureListener) { + this.delegate = delegate; + this.exceptionType = exception; + this.failureListener = failureListener; + Preconditions.checkArgument(delayInSeconds > 0, "Delay cannot be < 0"); + LOG.debug("Starting keep-alive execution on top of: {} with delay of: {} seconds", delegate, delayInSeconds); + scheduledFuture = executor.scheduleWithFixedDelay(this, delayInSeconds, delayInSeconds, TimeUnit.SECONDS); + } + + @Nonnull + public Optional<? extends DataObject> read(@Nonnull final InstanceIdentifier id, + @Nonnull final ReadContext ctx) throws ReadFailedException { + return delegate.read(id, ctx); + } + + public void readCurrentAttributes(@Nonnull final InstanceIdentifier<D> id, + @Nonnull final B builder, + @Nonnull final ReadContext ctx) throws ReadFailedException { + delegate.readCurrentAttributes(id, builder, ctx); + } + + @Nonnull + public B getBuilder(final InstanceIdentifier<D> id) { + return delegate.getBuilder(id); + } + + public void merge(@Nonnull final Builder<? extends DataObject> parentBuilder, + @Nonnull final D readValue) { + delegate.merge(parentBuilder, readValue); + } + + @Nonnull + @Override + public InstanceIdentifier<D> getManagedDataObjectType() { + return delegate.getManagedDataObjectType(); + } + + @Override + public void run() { + LOG.trace("Invoking keepalive"); + try { + final Optional<? extends DataObject> read = read(delegate.getManagedDataObjectType(), CTX); + LOG.debug("Keepalive executed successfully with data: {}", read); + } catch (Exception e) { + if (exceptionType.isAssignableFrom(e.getClass())) { + LOG.warn("Keepalive failed. Notifying listener", e); + failureListener.onKeepaliveFailure(); + } + LOG.warn("Keepalive failed unexpectedly", e); + throw new IllegalArgumentException("Unexpected failure during keep-alive execution", e); + } + } + + @Override + public void close() { + // Do not interrupt, it's not our executor + scheduledFuture.cancel(false); + } + + /** + * Listener that gets called whenever keepalive fails as expected + */ + public interface KeepaliveFailureListener { + + void onKeepaliveFailure(); + } + + private static final class NoopMappingContext implements MappingContext { + @Override + public <T extends DataObject> Optional<T> read(@Nonnull final InstanceIdentifier<T> currentId) { + return Optional.absent(); + } + + @Override + public void delete(final InstanceIdentifier<?> path) {} + + @Override + public <T extends DataObject> void merge(final InstanceIdentifier<T> path, final T data) {} + + @Override + public <T extends DataObject> void put(final InstanceIdentifier<T> path, final T data) {} + + @Override + public void close() {} + } + + private static class NoopReadContext implements ReadContext { + + private final ModificationCache modificationCache = new ModificationCache(); + + @Nonnull + @Override + public ModificationCache getModificationCache() { + return modificationCache; + } + + @Nonnull + @Override + public MappingContext getMappingContext() { + return new NoopMappingContext(); + } + + @Override + public void close() { + + } + } +} |