1 files changed, 60 insertions, 0 deletions
diff --git a/opendc/opendc-core/src/main/kotlin/com/atlarge/opendc/core/failure/FailureInjector.kt b/opendc/opendc-core/src/main/kotlin/com/atlarge/opendc/core/failure/FailureInjector.kt
new file mode 100644
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--- /dev/null
+++ b/opendc/opendc-core/src/main/kotlin/com/atlarge/opendc/core/failure/FailureInjector.kt
@@ -0,0 +1,60 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020 atlarge-research
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package com.atlarge.opendc.core.failure
+
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.isActive
+import java.util.Random
+import kotlin.coroutines.coroutineContext
+import kotlin.math.ln
+import kotlin.random.asKotlinRandom
+
+/**
+ * An entity that injects failures into a system.
+ *
+ * @param failureDomains The failure domains to be included.
+ */
+public class FailureInjector(private val failureDomains: List<FailureDomain>) {
+    /**
+     * The [Random] instance to generate the failures.
+     */
+    private val random = Random()
+
+    /**
+     * Start the failure injector process.
+     */
+    public suspend operator fun invoke() {
+        val targets = HashSet(failureDomains)
+        val mu = 20.0
+        while (targets.isNotEmpty() && coroutineContext.isActive) {
+            delay(random.expovariate(mu))
+            val target = targets.random(random.asKotlinRandom())
+            targets -= target
+            target.fail()
+        }
+    }
+
+    private fun Random.expovariate(mu: Double) = (-mu * ln(1 - nextDouble())).toLong()
+}