From c4016fcfd37550b237f6940eaffb5b4efd607601 Mon Sep 17 00:00:00 2001
From: Fabian Mastenbroek <mail.fabianm@gmail.com>
Date: Fri, 3 Apr 2020 17:05:05 +0200
Subject: feat: Add initial prototype for failure recovery

---
 .../opendc/core/failure/CorrelatedFaultInjector.kt | 24 ++++++++++++++++++++--
 .../atlarge/opendc/core/failure/FailureDomain.kt   |  5 +++++
 2 files changed, 27 insertions(+), 2 deletions(-)

(limited to 'opendc/opendc-core/src')

diff --git a/opendc/opendc-core/src/main/kotlin/com/atlarge/opendc/core/failure/CorrelatedFaultInjector.kt b/opendc/opendc-core/src/main/kotlin/com/atlarge/opendc/core/failure/CorrelatedFaultInjector.kt
index c5189764..f363bf45 100644
--- a/opendc/opendc-core/src/main/kotlin/com/atlarge/opendc/core/failure/CorrelatedFaultInjector.kt
+++ b/opendc/opendc-core/src/main/kotlin/com/atlarge/opendc/core/failure/CorrelatedFaultInjector.kt
@@ -44,6 +44,8 @@ public class CorrelatedFaultInjector(
     private val iatShape: Double,
     private val sizeScale: Double,
     private val sizeShape: Double,
+    private val dScale: Double,
+    private val dShape: Double,
     random: Random = Random(0)
 ) : FaultInjector {
     /**
@@ -84,7 +86,7 @@ public class CorrelatedFaultInjector(
         }
 
         job = this.domain.launch {
-            while (true) {
+            while (active.isNotEmpty()) {
                 ensureActive()
 
                 // Make sure to convert delay from hours to milliseconds
@@ -98,10 +100,28 @@ public class CorrelatedFaultInjector(
                 delay(d.toLong())
 
                 val n = lognvariate(sizeScale, sizeShape).toInt()
-                for (failureDomain in active.shuffled(random).take(n)) {
+                val targets = active.shuffled(random).take(n)
+                for (failureDomain in targets) {
+                    active -= failureDomain
                     failureDomain.fail()
                 }
+
+                val df = lognvariate(dScale, dShape) * 3600 * 1e6
+
+                // Handle long overflow
+                if (simulationContext.clock.millis() + df <= 0) {
+                    return@launch
+                }
+
+                delay(df.toLong())
+
+                for (failureDomain in targets) {
+                    failureDomain.recover()
+                    enqueue(failureDomain)
+                }
             }
+
+            job = null
         }
     }
 
diff --git a/opendc/opendc-core/src/main/kotlin/com/atlarge/opendc/core/failure/FailureDomain.kt b/opendc/opendc-core/src/main/kotlin/com/atlarge/opendc/core/failure/FailureDomain.kt
index 91ca9b83..d56df3c9 100644
--- a/opendc/opendc-core/src/main/kotlin/com/atlarge/opendc/core/failure/FailureDomain.kt
+++ b/opendc/opendc-core/src/main/kotlin/com/atlarge/opendc/core/failure/FailureDomain.kt
@@ -39,4 +39,9 @@ public interface FailureDomain {
      * Fail the domain externally.
      */
     public suspend fun fail()
+
+    /**
+     * Resume the failure domain.
+     */
+    public suspend fun recover()
 }
-- 
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