From 5f1472dbb75717942cd72c86f9c5af3406ea9c7d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cl=C3=A9ment=20Pit-Claudel?= <clement.pit-claudel@epfl.ch>
Date: Sun, 22 Dec 2024 00:19:54 +0100
Subject: [PATCH] server/gc: User time.Instant instead of milliseconds and add
logging
---
.../webapp/server/web/GarbageCollector.scala | 37 +++++++++++++------
.../cs214/webapp/server/web/ServerApp.scala | 11 +++---
.../cs214/webapp/server/web/WebServer.scala | 4 +-
3 files changed, 34 insertions(+), 18 deletions(-)
diff --git a/jvm/src/main/scala/cs214/webapp/server/web/GarbageCollector.scala b/jvm/src/main/scala/cs214/webapp/server/web/GarbageCollector.scala
index b8e921f..e97ea26 100644
--- a/jvm/src/main/scala/cs214/webapp/server/web/GarbageCollector.scala
+++ b/jvm/src/main/scala/cs214/webapp/server/web/GarbageCollector.scala
@@ -3,26 +3,41 @@ package server.web
import scala.collection.concurrent
import scala.concurrent.duration.*
+import scala.jdk.DurationConverters.*
+
+import java.time.Instant
object GarbageCollector:
- private val GC_TICK = 1.minutes
- private val GC_CREATION_TIME_GRACE_PERIOD = 1.hour
- private val GC_LAST_ACTIVITY_GRACE_PERIOD = 3.days
+ private val GC_TICK = 5.minutes
+ private val GC_CREATION_TIME_GRACE_PERIOD = 1.hour.toJava
+ private val GC_LAST_ACTIVITY_GRACE_PERIOD = 3.days.toJava
- def garbageCollect(): Unit = // Not safe, needs lock or care; too slow?
- val now = System.currentTimeMillis()
- val lastActivityThreshold = now - GC_LAST_ACTIVITY_GRACE_PERIOD.toMillis
- val creationTimeThreshold = now - GC_CREATION_TIME_GRACE_PERIOD.toMillis
+ def garbageCollect(): Unit =
+ val now = Instant.now()
+ val lastActivityThreshold = now.minus(GC_LAST_ACTIVITY_GRACE_PERIOD)
+ val creationTimeThreshold = now.minus(GC_CREATION_TIME_GRACE_PERIOD)
+ println(f"[gc] Collection started at $now")
+ println(f"[gc] Collection criteria:\n" +
+ f"[gc] Created before: $creationTimeThreshold\n" +
+ f"[gc] Last active before: $lastActivityThreshold")
WebServer.instances.snapshot()
.values.filter: inst =>
- inst.lastActivity < collectInactiveBefore &&
- inst.creationTime < collectNeverConnectedBefore
+ val lastActivity = inst.lastActivity
+ lastActivity.isBefore(lastActivityThreshold) &&
+ inst.creationTime.isBefore(creationTimeThreshold) && {
+ println(f"[gc] Marking ${inst.appInfo.id}/${inst.instanceId} for collection:\n" +
+ f"[gc] Activity: $lastActivity < $lastActivityThreshold\n" +
+ f"[gc] Creation: ${inst.creationTime} < $creationTimeThreshold")
+ true
+ }
.toList.foreach: inst =>
- println(f"[gc] Stopping ${inst.appInfo.name}/${inst.instanceId}.")
+ println(f"[gc] Stopping ${inst.appInfo.id}/${inst.instanceId}.")
WebServer.shutdownApp(inst.instanceId)
+ println("[gc] Collection complete")
private val clock =
val scheduler = Clock.newScheduler()
Clock("gc", GC_TICK.toMillis)(using scheduler)(garbageCollect())
- clock.start()
+ def start() = clock.start()
+ def shutdown() = clock.shutdown()
diff --git a/jvm/src/main/scala/cs214/webapp/server/web/ServerApp.scala b/jvm/src/main/scala/cs214/webapp/server/web/ServerApp.scala
index a0ed290..4b2313b 100644
--- a/jvm/src/main/scala/cs214/webapp/server/web/ServerApp.scala
+++ b/jvm/src/main/scala/cs214/webapp/server/web/ServerApp.scala
@@ -3,7 +3,8 @@ package server
package web
import java.util.concurrent.ScheduledExecutorService
-import java.util.concurrent.atomic.AtomicLong
+import java.util.concurrent.atomic.AtomicReference
+import java.time.Instant
import scala.collection.mutable
import scala.util.{Success, Failure, Try}
@@ -58,11 +59,11 @@ private[web] abstract class ServerApp:
*/
def transition(clients: Seq[UserId])(userId: UserId, eventJs: ujson.Value): Try[PendingActions]
- val creationTime = System.currentTimeMillis()
+ val creationTime = Instant.now
- private var _lastActivity = AtomicLong(0)
- def recordActivity() = lastActivity.set(System.currentTimeMillis())
- def lastActivity = lastActivity.get()
+ private var _lastActivity = AtomicReference(Instant.MIN)
+ def recordActivity() = _lastActivity.set(Instant.now)
+ def lastActivity = _lastActivity.get()
private val channels =
mutable.Map[UserId, mutable.Set[cask.WsChannelActor]]().withDefault(_ => mutable.Set())
diff --git a/jvm/src/main/scala/cs214/webapp/server/web/WebServer.scala b/jvm/src/main/scala/cs214/webapp/server/web/WebServer.scala
index c33e612..88e1e61 100644
--- a/jvm/src/main/scala/cs214/webapp/server/web/WebServer.scala
+++ b/jvm/src/main/scala/cs214/webapp/server/web/WebServer.scala
@@ -23,8 +23,6 @@ private case class Wordlist(fname: String):
/** Contains the web server state and functionalities */
object WebServer:
- GarbageCollector.start()
-
private val instanceIdsFileName = "eff_short_wordlist_1.txt" // Where to find the list of possible instance ids
private val instanceIdLength = 4 // How many words do we concatenate for the instance id
private val instanceIdWords = Wordlist(instanceIdsFileName)
@@ -69,3 +67,5 @@ object WebServer:
instances.remove(instanceId).map: app =>
app.shutdown()
println(s"[${app.appInfo.id}][$instanceId] shut down")
+
+ GarbageCollector.start()
--
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