Adding a Clumsy meal backfill to help with error testing.

service/src/test/kotlin/app/cash/backfila/development/finedining/ClumsyMealsBackfill.kt

@@ -0,0 +1,46 @@
+package app.cash.backfila.development.finedining
+
+import app.cash.backfila.client.BackfillConfig
+import app.cash.backfila.client.Description
+import app.cash.backfila.client.PrepareBackfillConfig
+import app.cash.backfila.client.stat.StaticDatasourceBackfill
+import javax.inject.Inject
+import wisp.logging.getLogger
+
+class ClumsyMealsBackfill @Inject constructor() : StaticDatasourceBackfill<String, ClumsyMealsBackfill.ClumsyMealsAttributes>() {
+  var servedPlates = 0 // Keeps track of the number of successfully served plates.
+  var brokenPlatesSoFar = 0 // When plates break it keeps track of how many have broken so far.
+  override fun validate(config: PrepareBackfillConfig<ClumsyMealsAttributes>) {
+    if (config.parameters.blockedEntrance) {
+      throw RuntimeException("Entrance is BLOCKED. No customers can be served!")
+    }
+  }
+
+  override fun runOne(item: String, config: BackfillConfig<ClumsyMealsAttributes>) {
+    Thread.sleep(100L) // Sleep for half a second
+    // We potentially break on every 25th plate.
+    if (servedPlates % 25 == 0 && brokenPlatesSoFar < config.parameters.brokenPlates) {
+      brokenPlatesSoFar++
+      logger.info { "Broke a plate!" }
+      throw RuntimeException("Failed to serve: Broke a plate!!!")
+    }
+    logger.info { "Poorly served $item" }
+    servedPlates++
+    brokenPlatesSoFar = 0
+  }
+
+  @Description("Adaptable clumsiness.")
+  data class ClumsyMealsAttributes(
+    @Description("Whether the entrance is blocked or not. Can be used to test Prepare failures.")
+    val blockedEntrance: Boolean = true,
+    @Description("How many plates break before a successful plate is served. Can be used to test retry logic.")
+    val brokenPlates: Int = 1,
+  )
+
+  // Generate the meal place settings for the backfill.
+  override val staticDatasource: List<String> = (1..5000).map { i -> "place setting $i" }
+
+  companion object {
+    private val logger = getLogger<ClumsyMealsBackfill>()
+  }
+}

service/src/test/kotlin/app/cash/backfila/development/finedining/FineDiningServiceModule.kt

@@ -19,5 +19,6 @@ internal class FineDiningServiceModule : KAbstractModule() {
       ),
     )
     install(StaticDatasourceBackfillModule.create<SlowMealsBackfill>())
+    install(StaticDatasourceBackfillModule.create<ClumsyMealsBackfill>())
   }
 }

service/src/test/kotlin/app/cash/backfila/development/finedining/SlowMealsBackfill.kt

@@ -12,11 +12,11 @@ class SlowMealsBackfill @Inject constructor() : StaticDatasourceBackfill<String,
   }
 
   data class SlowMealsAttributes(
-    val mealDelayMs: Long = 1000L,
+    val mealDelayMs: Long = 100L,
   )
 
   // Generate the meal place settings for the backfill.
-  override val staticDatasource: List<String> = (1..1000).map { i -> "place setting $i" }
+  override val staticDatasource: List<String> = (1..5000).map { i -> "place setting $i" }
 
   companion object {
     private val logger = getLogger<SlowMealsBackfill>()