Saga token gets updated during exception

Axon Framework
, ,
1

The following is my gradle kotlin spring-boot project’s configuration and saga:
person service application.properties:

spring.datasource.url=jdbc:postgresql://${DB_HOST:localhost}:${DB_PORT:5432}/demodb
spring.datasource.username=${DB_USER:postgres}
spring.datasource.password=${DB_PASSWORD:postgres}
spring.jpa.database-platform=org.hibernate.dialect.PostgreSQLDialect
spring.jpa.hibernate.ddl-auto=update
server.port=${PORT:8081}

store service application.properties:

spring.datasource.url=jdbc:postgresql://${DB_HOST:localhost}:${DB_PORT:5432}/demodb
spring.datasource.username=${DB_USER:postgres}
spring.datasource.password=${DB_PASSWORD:postgres}
spring.jpa.database-platform=org.hibernate.dialect.PostgreSQLDialect
spring.jpa.hibernate.ddl-auto=update
server.port=${PORT:8082}

using dependencies:

    org.axonframework:axon-bom version 4.6.0
    org.springframework.boot version 2.7.5
    kotlin version 1.6.21
    postgres

Using a saga:

package com.example.person

import com.example.common.PersonEvents
import com.example.common.StoreCommands as storeCommands
import com.example.common.StoreEvents as storeEvents

import com.example.common.PersonCommands as personCommands
import org.axonframework.commandhandling.gateway.CommandGateway
import org.axonframework.modelling.saga.EndSaga
import org.axonframework.modelling.saga.SagaEventHandler
import org.axonframework.modelling.saga.StartSaga
import org.axonframework.spring.stereotype.Saga
import org.springframework.beans.factory.annotation.Autowired

@Saga
class PersonShoppingSaga {
    @Transient
    @Autowired
    lateinit var commandGateway: CommandGateway

    lateinit var name: String
    var listNumber: Int = 0
    lateinit var shoppingList: List<String>
    var shopping: Boolean = false

    @StartSaga
    @SagaEventHandler(associationProperty = "name")
    fun handle(event: PersonEvents.shoppingListRecieved){
        if (shopping) {
            TODO() // person is already shopping, ask processor to wait longer.
        }

        shopping = true
        shoppingList = event.list
        name = event.name

        walkToStore()
    }

    @SagaEventHandler(associationProperty = "person", keyName = "name")
    fun handle(event: storeEvents.travelledToStore){
        listNumber ++
        walkToStore()
    }

    fun walkToStore(){
        if (listNumber == shoppingList.size -1) {
            commandGateway.sendAndWait<personCommands>(personCommands.finishedShopping(name, shoppingList))
        }
        commandGateway.sendAndWait<storeCommands>(storeCommands.travelToStore(shoppingList.get(listNumber), name))
    }

    @EndSaga
    @SagaEventHandler(associationProperty = "name")
    fun handle(event: PersonEvents.shoppingListCompleted){
        println("completed shopping list")
    }
}

When there is a random amount of chances for failure in the “travelToStore” command, when I run the example project, and restart the service, the saga does not retry consuming the event that caused an exception and continues consuming new events.

Is there some configuration that I can set to make the saga not continue with the next event untill the events were processed successfully?

2

I’m not sure where that error is triggered. It’s likely through you need to configure an error handler such that the error is not just logged.

3

So to be clear, the default behaviour for a saga is to only log the exception then continue?

4

I do think indeed the default error handler for all event processors, so also for the one handling saga’s is the LoggingErrorHandler.