Use the properties of the slo checker and add lag trend percent

Specific slo checker should be defined with a propertie map to be more generic.
Further add a lag trend percent slo, which use a percentage of the defined load
to compute the allowed threshold.

theodolite/examples/operator/example-execution.yaml

@@ -12,11 +12,19 @@ spec:
     resourceValues: [1, 2, 3, 4, 5]
   slos:
     - sloType: "lag trend"
-      threshold: 2000
       prometheusUrl: "http://prometheus-operated:9090"
-      externalSloUrl: "http://localhost:80/evaluate-slope"
       offset: 0
-      warmup: 60 # in seconds
+      properties:
+        threshold: 2000
+        externalSloUrl: "http://localhost:80/evaluate-slope"
+        warmup: 60 # in seconds
+    # - sloType: "lag trend percent"
+    #   prometheusUrl: "http://localhost:9090"
+    #   offset: 0
+    #   properties:
+    #     percent: 5
+    #     externalSloUrl: "http://localhost:80/evaluate-slope"
+    #     warmup: 60 # in seconds
   execution:
     strategy: "LinearSearch"
     duration: 300 # in seconds

theodolite/src/main/kotlin/theodolite/benchmark/BenchmarkExecution.kt

@@ -62,11 +62,9 @@ class BenchmarkExecution : KubernetesResource {
     @RegisterForReflection
     class Slo : KubernetesResource {
         lateinit var sloType: String
-        var threshold by Delegates.notNull<Int>()
         lateinit var prometheusUrl: String
-        lateinit var externalSloUrl: String
         var offset by Delegates.notNull<Int>()
-        var warmup by Delegates.notNull<Int>()
+        lateinit var properties: MutableMap<String, String>
     }
 
     /**

theodolite/src/main/kotlin/theodolite/evaluation/AnalysisExecutor.kt

@@ -64,9 +64,8 @@ class AnalysisExecutor(
 
             val sloChecker = SloCheckerFactory().create(
                 sloType = slo.sloType,
-                externalSlopeURL = slo.externalSloUrl,
-                threshold = slo.threshold,
-                warmup = slo.warmup
+                properties = slo.properties,
+                load = load
             )
 
             result = sloChecker.evaluate(prometheusData)

theodolite/src/main/kotlin/theodolite/evaluation/SloCheckerFactory.kt

 package theodolite.evaluation
 
+import theodolite.util.LoadDimension
+
 /**
  * Factory used to potentially create different [SloChecker]s.
  * Supports: lag type.
@@ -20,16 +22,28 @@ class SloCheckerFactory {
      */
     fun create(
         sloType: String,
-        externalSlopeURL: String,
-        threshold: Int,
-        warmup: Int
+        properties: MutableMap<String, String>,
+        load: LoadDimension
     ): SloChecker {
         return when (sloType) {
             "lag trend" -> ExternalSloChecker(
-                externalSlopeURL = externalSlopeURL,
-                threshold = threshold,
-                warmup = warmup
+                externalSlopeURL = properties["externalSloUrl"] ?: throw IllegalArgumentException("externalSloUrl expected"),
+                threshold = properties["threshold"]?.toInt() ?: throw IllegalArgumentException("threshold expected"),
+                warmup = properties["warmup"]?.toInt() ?: throw IllegalArgumentException("warmup expected")
             )
+            "lag trend percent" -> {
+                var thresholdPercent = properties["percent"]?.toInt() ?: throw IllegalArgumentException("percent for threshold expected")
+                if (thresholdPercent < 0 || thresholdPercent > 100) {
+                    throw IllegalArgumentException("Threshold percent need to be an Int in the range between 0 and 100 (inclusive)")
+                }
+                var threshold = (load.get() / 100.0 * thresholdPercent).toInt()
+
+                ExternalSloChecker(
+                    externalSlopeURL = properties["externalSloUrl"] ?: throw IllegalArgumentException("externalSloUrl expected"),
+                    threshold = threshold,
+                    warmup = properties["warmup"]?.toInt() ?: throw IllegalArgumentException("warmup expected")
+                )
+            }
             else -> throw IllegalArgumentException("Slotype $sloType not found.")
         }
     }