docs: Start from snapshot for drone push projection

akka · Oct 18, 2023 · 0317a89 · 0317a89
1 parent b708b15
commit 0317a89
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Showing 4 changed files with 20 additions and 1 deletion.
diff --git a/samples/grpc/local-drone-control-scala/src/main/resources/persistence-h2.conf b/samples/grpc/local-drone-control-scala/src/main/resources/persistence-h2.conf
@@ -27,3 +27,7 @@ akka {
     }
   }
 }
+
+// #startFromSnapshot
+akka.persistence.r2dbc.query.start-from-snapshot.enabled = true
+// #startFromSnapshot
diff --git a/samples/grpc/local-drone-control-scala/src/main/resources/persistence-postgres.conf b/samples/grpc/local-drone-control-scala/src/main/resources/persistence-postgres.conf
@@ -31,3 +31,5 @@ akka {
     }
   }
 }
+
+akka.persistence.r2dbc.query.start-from-snapshot.enabled = true
diff --git a/samples/grpc/local-drone-control-scala/src/main/scala/local/drones/Drone.scala b/samples/grpc/local-drone-control-scala/src/main/scala/local/drones/Drone.scala
@@ -96,6 +96,11 @@ object Drone {
         .receiveSignal { case (_, PostStop) =>
           telemetry.droneEntityPassivated()
         }
+        // #startFromSnapshot
+        .snapshotWhen { (_, event, _) =>
+          event.isInstanceOf[CoarseGrainedLocationChanged]
+        }
+    // #startFromSnapshot
     }
 
   // #commandHandler

diff --git a/samples/grpc/local-drone-control-scala/src/main/scala/local/drones/DroneEvents.scala b/samples/grpc/local-drone-control-scala/src/main/scala/local/drones/DroneEvents.scala
@@ -101,7 +101,15 @@ object DroneEvents {
         EventProducerSettings(system),
         // only push coarse grained coordinate changes
         producerFilter = envelope =>
-          envelope.event.isInstanceOf[Drone.CoarseGrainedLocationChanged]),
+          envelope.event.isInstanceOf[Drone.CoarseGrainedLocationChanged])
+        // #startFromSnapshot
+        // start from latest drone snapshot and don't replay history
+        .withStartingFromSnapshots[
+          Drone.State,
+          Drone.CoarseGrainedLocationChanged](state =>
+          Drone.CoarseGrainedLocationChanged(
+            state.coarseGrainedCoordinates.get)),
+      // #startFromSnapshot
       GrpcClientSettings.fromConfig("central-drone-control"))
 
     def projectionForPartition(
-Original file line number
+Diff line change
@@ Expand Up / @@ -31,3 +31,5 @@ akka { @@
         }
       }
     }
+    akka.persistence.r2dbc.query.start-from-snapshot.enabled = true