Github user steveloughran commented on a diff in the pull request:
https://github.com/apache/spark/pull/6935#discussion_r46672762
--- Diff:
core/src/main/scala/org/apache/spark/deploy/history/ApplicationCache.scala ---
@@ -0,0 +1,579 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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 org.apache.spark.deploy.history
+
+import java.util.NoSuchElementException
+
+import javax.servlet.http.{HttpServletRequest, HttpServletResponse}
+import javax.servlet.{DispatcherType, Filter, FilterChain, FilterConfig,
ServletException, ServletRequest, ServletResponse}
+
+import scala.collection.JavaConverters._
+
+import com.codahale.metrics.{Counter, MetricRegistry, Timer}
+import com.google.common.cache.{CacheBuilder, CacheLoader, LoadingCache,
RemovalListener, RemovalNotification}
+import com.google.common.util.concurrent.ListenableFuture
+import org.eclipse.jetty.servlet.FilterHolder
+
+import org.apache.spark.Logging
+import org.apache.spark.metrics.source.Source
+import org.apache.spark.ui.SparkUI
+import org.apache.spark.util.Clock
+
+/**
+ * Cache for applications.
+ *
+ * Completed applications are cached for as long as there is capacity for
them.
+ * Incompleted applications have their update time checked on every
+ * retrieval; if the cached entry is out of date, it is refreshed.
+ *
+ * @param operations implementation of record access operations
+ * @param refreshInterval interval between refreshes in milliseconds.
+ * @param retainedApplications number of retained applications
+ * @param clock time source
+ */
+private[history] class ApplicationCache(val operations:
ApplicationCacheOperations,
+ val refreshInterval: Long,
+ val retainedApplications: Int,
+ val clock: Clock) extends Logging {
+
+ /**
+ * Services the load request from the cache.
+ */
+ private val appLoader = new CacheLoader[CacheKey, CacheEntry] {
+
+ /** the cache key doesn't match an cached entry ... attempt to load it
*/
+ override def load(key: CacheKey): CacheEntry = {
+ loadApplicationEntry(key.appId, key.attemptId)
+ }
+
+ override def reload(key: CacheKey, oldValue: CacheEntry):
ListenableFuture[CacheEntry] = super
+ .reload(key, oldValue)
+ }
+
+ /**
+ * Handler for callbacks from the cache of entry removal.
+ */
+ private val removalListener = new RemovalListener[CacheKey, CacheEntry] {
+
+ /**
+ * Removal event notifies the provider to detach the UI.
+ * @param rm removal notification
+ */
+ override def onRemoval(rm: RemovalNotification[CacheKey, CacheEntry]):
Unit = {
+ metrics.evictionCount.inc()
+ val key = rm.getKey
+ logDebug(s"Evicting entry ${key}")
+ operations.detachSparkUI(key.appId, key.attemptId, rm.getValue().ui)
+ }
+ }
+
+ /**
+ * The cache of applications.
+ * Tagged as protected so as to allow subclasses in tests to accesss it
directly
+ */
+ protected val appCache: LoadingCache[CacheKey, CacheEntry] =
CacheBuilder.newBuilder()
+ .maximumSize(retainedApplications)
+ .removalListener(removalListener)
+ .build(appLoader)
+
+ /**
+ * The metrics which are updated as the cache is used
+ */
+ val metrics = new CacheMetrics("history.cache")
+
+ init()
+
+ /**
+ * Perform any startup operations. This includes declaring this instance
+ * as the cache to use in the [[ApplicationCacheCheckFilterRelay]].
+ */
+ private def init(): Unit = {
+ ApplicationCacheCheckFilterRelay.setApplicationCache(this)
+ }
+
+ /** stop the cache */
+ def stop(): Unit = {
+ ApplicationCacheCheckFilterRelay.resetApplicationCache()
+ }
+
+ /**
+ * Get an entry. Cache fetch/refresh will have taken place by
+ * the time this method returns.
+ * @param appAndAttempt application to look up in the format needed by
the history server web UI,
+ * `appId/attemptId` or `appId`.
+ * @return the entry
+ */
+ def get(appAndAttempt: String): SparkUI = {
+ val parts = splitAppAndAttemptKey(appAndAttempt)
+ get(parts._1, parts._2)
+ }
+
+ /**
+ * Get the associated spark UI. Cache fetch/refresh will have taken
place by
+ * the time this method returns.
+ * @param appId application ID
+ * @param attemptId optional attempt ID
+ * @return the entry
+ */
+ def get(appId: String, attemptId: Option[String]): SparkUI = {
+ lookupAndUpdate(appId, attemptId)._1.ui
+ }
+
+ /**
+ * Look up the entry; update it if needed.
+ * @param appId application ID
+ * @param attemptId optional attempt ID
+ * @return the underlying cache entry -which can have its timestamp
changed, and a flag to
+ * indicate that the entry has changed
+ */
+ private def lookupAndUpdate(appId: String, attemptId: Option[String]):
(CacheEntry, Boolean) = {
+ metrics.lookupCount.inc()
+ val cacheKey = CacheKey(appId, attemptId)
+ var entry = appCache.getIfPresent(cacheKey)
+ var updated = false
+ if (entry == null) {
+ // no entry, so fetch without any post-fetch probes for
out-of-dateness
+ entry = appCache.get(cacheKey)
+ } else if (!entry.completed) {
+ val now = clock.getTimeMillis()
+ if (now - entry.probeTime > refreshInterval) {
+ log.debug(s"Probing @time $now for updated application $cacheKey
-> $entry")
+ metrics.updateProbeCount.inc()
+ updated = time(metrics.updateProbeTimer) {
+ operations.isUpdated(appId, attemptId, entry.loadTime)
+ }
+ if (updated) {
+ logDebug(s"refreshing $cacheKey")
+ metrics.updateTriggeredCount.inc()
+ appCache.refresh(cacheKey)
+ // and repeat the lookup
+ entry = appCache.get(cacheKey)
+ } else {
+ // update the probe timestamp to the current time
+ entry.probeTime = now
+ }
+ }
+ }
+ (entry, updated)
+ }
+
+ /**
+ * This method is visible for testing. It looks up the cached entry *and
returns a clone of it*.
+ * This ensures that the cached entries never leak
+ * @param appId application ID
+ * @param attemptId optional attempt ID
+ * @return a new entry with shared SparkUI, but copies of the other
fields.
+ */
+ def lookupCacheEntry(appId: String, attemptId: Option[String]):
CacheEntry = {
+ val entry = lookupAndUpdate(appId, attemptId)._1
+ new CacheEntry(entry.ui, entry.completed, entry.data, entry.loadTime,
entry.probeTime)
+ }
+
+ /**
+ * Probe for an application being updated
+ * @param appId application ID
+ * @param attemptId attempt ID
+ * @return true if an update has been triggered
+ */
+ def checkForUpdates(appId: String, attemptId: Option[String]): Boolean =
{
+ val (entry, updated) = lookupAndUpdate(appId, attemptId)
+ updated
+ }
+
+ /**
+ * Size probe, primarily for testing
+ * @return size
+ */
+ def size(): Long = appCache.size()
+
+ /**
+ * Emptiness predicate, primarily for testing
+ * @return true if the cache is empty
+ */
+ def isEmpty: Boolean = appCache.size() == 0
+
+ /**
+ * Time a closure, returning its output.
+ * @param t timer
+ * @param f function
+ * @tparam T type of return value of time
+ * @return the result of the function.
+ */
+ private def time[T](t: Timer)(f: => T): T = {
+ val timeCtx = t.time()
+ try {
+ f
+ } finally {
+ timeCtx.close()
+ }
+ }
+
+ /**
+ * Load the Spark UI via [[ApplicationCacheOperations.getAppUI()]],
+ * then attach it to the web UI via
[[ApplicationCacheOperations.attachSparkUI()]].
+ *
+ * The generated entry contains the UI and the current timestamp.
+ * The timer [[metrics.loadTimer]] tracks the time taken to load the UI.
+ *
+ * @param appId application ID
+ * @param attemptId optional attempt ID
+ * @return the cache entry
+ * @throws NoSuchElementException if there is no matching element
+ */
+ @throws[NoSuchElementException]
+ def loadApplicationEntry(appId: String, attemptId: Option[String]):
CacheEntry = {
+ logDebug(s"Loading application Entry $appId/$attemptId")
+ metrics.loadCount.inc()
+ time(metrics.loadTimer) {
+ operations.getAppUI(appId, attemptId) match {
+ case Some((ui, loadTime, data)) =>
+ val completed =
ui.getApplicationInfoList.exists(_.attempts.last.completed)
+ // attach the spark UI
+ if (completed) {
+ operations.attachSparkUI(appId, attemptId, ui, completed)
+ } else {
+ // register the filters
+ ApplicationCacheCheckFilterRelay.registerFilter(ui, appId,
attemptId)
+ operations.attachSparkUI(appId, attemptId, ui, completed)
+ }
+ // build the cache entry
+ val now = clock.getTimeMillis()
+ val entry = new CacheEntry(ui, completed, data, if (loadTime> 0)
loadTime else now , now)
+ logDebug(s"Loaded application $appId/$attemptId -> $entry")
+ entry
+ case None =>
+ metrics.lookupFailureCount.inc()
+ // guava's cache logs via java.util log, so is of limited use.
Hence: our own message
+ logInfo(s"Failed to load application attempt $appId/$attemptId")
+ throw new NoSuchElementException(s"no application with
application Id '$appId'" +
+ attemptId.map { id => s" attemptId '$id'" }.getOrElse(" and
no attempt Id"))
+ }
+ }
+ }
+
+ /**
+ * Split up an `applicationId/attemptId` or `applicationId` key into the
separate pieces.
+ *
+ * @param appAndAttempt combined key
+ * @return a tuple of the application ID and, if present, the attemptID
+ */
+ def splitAppAndAttemptKey(appAndAttempt: String): (String,
Option[String]) = {
+ val parts = appAndAttempt.split("/")
+ require(parts.length == 1 || parts.length == 2, s"Invalid app key
$appAndAttempt")
+ val appId = parts(0)
+ val attemptId = if (parts.length > 1) Some(parts(1)) else None
+ (appId, attemptId)
+ }
+
+ /**
+ * Merge an appId and optional attempt Id into a key of the form
`applicationId/attemptId`
+ * if there is an `attemptId`; `applicationId` if not.
+ * @param appId application ID
+ * @param attemptId optional attempt ID
+ * @return a unified string
+ */
+ def mergeAppAndAttemptToKey(appId: String, attemptId: Option[String]):
String = {
+ appId + attemptId.map { id => s"/$id" }.getOrElse("")
+ }
+
+ /**
+ * String operator dumps the cache entries and metrics.
+ * @return a string value, primarily for testing and diagnostics
+ */
+ override def toString: String = {
+ val sb = new
StringBuilder(s"ApplicationCache(refreshInterval=$refreshInterval," +
+ s" retainedApplications= $retainedApplications)")
+ sb.append(s"; time = ${clock.getTimeMillis()}")
+ sb.append(s"; entry count= ${appCache.size()}\n")
+ sb.append("----\n")
+ appCache.asMap().asScala.foreach {
+ case(key, entry) => sb.append(s" $key -> $entry\n")
+ }
+ sb.append("----\n")
+ sb.append(metrics)
+ sb.append("----\n")
+ sb.toString()
+ }
+}
+
+/**
+ * An entry in the cache.
+ *
+ * @param ui Spark UI
+ * @param completed: flag to indicated that the application has completed
(and so
+ * does not need refreshing)
+ * @param probeTime timestamp in milliseconds. This may be updated during
probes
+ */
+private[history] final class CacheEntry(val ui: SparkUI, val completed:
Boolean,
+ val data: Option[Any],
+ val loadTime: Long,
+ var probeTime: Long) {
+
+ /** string value is for test assertions */
+ override def toString: String = {
+ s"UI $ui, data=$data, completed=$completed, loadTime=$loadTime
probeTime=$probeTime"
+ }
+}
+
+/**
+ * Cache key: compares on App Id and then, if non-empty, attemptId.
+ * The [[hashCode()]] function uses the same fields.
+ * @param appId application ID
+ * @param attemptId attempt ID
+ */
+private[history] final case class CacheKey(appId: String, attemptId:
Option[String]) {
+
+ override def hashCode(): Int = {
+ appId.hashCode() + attemptId.map(_.hashCode).getOrElse(0)
+ }
+
+ override def equals(obj: Any): Boolean = {
+ val that = obj.asInstanceOf[CacheKey]
+ that.appId == appId && that.attemptId == attemptId
+ }
+
+ override def toString: String = {
+ appId + attemptId.map { id => s"/$id" }.getOrElse("")
+ }
+}
+
+private[history] class CacheMetrics(prefix: String) extends Source {
+
+ /* metrics: counters and timers */
+ val lookupCount = new Counter()
+ val lookupFailureCount = new Counter()
+ val evictionCount = new Counter()
+ val loadCount = new Counter()
+ val loadTimer = new Timer()
+ val updateProbeCount = new Counter()
+ val updateProbeTimer = new Timer()
+ val updateTriggeredCount = new Counter()
+
+ /** all the counters: for registration and string conversion. */
+ private val counters = Seq(
+ ("lookup.count", lookupCount),
+ ("lookup.failure.count", lookupFailureCount),
+ ("eviction.count", evictionCount),
+ ("load.count", loadCount),
+ ("update.probe.count", updateProbeCount),
+ ("update.triggered.count", updateTriggeredCount))
+
+ /** all metrics, including timers */
+ private val allMetrics = counters ++ Seq(
+ ("load.timer", loadTimer),
+ ("update.probe.timer", updateProbeTimer))
+
+ /**
+ * Name of metric source
+ */
+ override val sourceName = "ApplicationCache"
+
+ override def metricRegistry: MetricRegistry = new MetricRegistry
+
+ /**
+ * Startup actions.
+ * This includes registering metrics with [[metricRegistry]]
+ */
+ private def init(): Unit = {
+ allMetrics.foreach(e =>
+ metricRegistry.register(MetricRegistry.name(prefix, e._1), e._2))
+ }
+
+ override def toString: String = {
+ val sb = new StringBuilder()
+ counters.foreach { e =>
+ sb.append(e._1).append(" = ").append(e._2.getCount).append('\n')
+ }
+ sb.toString()
+ }
+}
+
+/**
+ * API for cache events. That is: loading an APP UI; probing for it
changing, and for
+ * attaching/detaching the UI to and from the Web UI.
+ */
+private[history] trait ApplicationCacheOperations {
+
+ /**
+ * Get the application UI.
+ * @param appId application ID
+ * @param attemptId attempt ID
+ * @return If found, the Spark UI and any history information to be used
in the cache
+ */
+ def getAppUI(appId: String, attemptId: Option[String]): Option[(SparkUI,
Long, Option[Any])]
+
+ /**
+ * Attach a reconstructed UI.
+ * @param appId application ID
+ * @param attemptId attempt ID
+ * @param ui UI
+ * @param completed flag to indicate that the UI has completed
+ */
+ def attachSparkUI(appId: String,
+ attemptId: Option[String],
+ ui: SparkUI,
+ completed: Boolean): Unit
+
+ /**
+ * Detach a Spark UI.
+ *
+ * @param ui Spark UI
+ */
+ def detachSparkUI(appId: String, attemptId: Option[String], ui:
SparkUI): Unit
+
+ /**
+ * Probe for an update to an (incompleted) application.
+ * @param appId application ID
+ * @param attemptId optional attempt ID
+ * @param updateTimeMillis time in milliseconds to use as the threshold
for an update.
+ * @param data any other data the operations implementation can use to
determine age
--- End diff --
I'll tell you why: other providers should have the right to attach other
bits of information they need. I haven't actually glued up the YARN timeline
server to this, yet, but would work differently, maybe timestamps, maybe
something else.
I don't know what other providers are out there, and don't want to block
them out.
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastruct...@apache.org or file a JIRA ticket
with INFRA.
---
---------------------------------------------------------------------
To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org
For additional commands, e-mail: reviews-h...@spark.apache.org
