Spring cloud data flow task Invalid TaskExecution ID - spring-cloud-dataflow

Question

I am just trying to create a hello world SCDF task. It is my understanding that out of the box the task should be able to read the needed data from the h2 database by just including h2 in the pom, but I am wondering if that is the correct assumption. Can anybody lend any suggestions to why I am getting the following error: 'taskLifecycleListener'; nested exception is java.lang.IllegalArgumentException: Invalid TaskExecution, ID...
Task
package com.hello;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.task.configuration.EnableTask;
import org.springframework.context.annotation.Bean;
#SpringBootApplication
#EnableTask
public class HelloTask {
#Bean
public CommandLineRunner commandLineRunner() {
return new HelloWorldCommandLineRunner();
}
public static void main(String[] args) {
SpringApplication.run(HelloTask.class, args);
}
public static class HelloWorldCommandLineRunner implements CommandLineRunner {
public void run(String... strings) throws Exception {
System.out.println("Hello World!");
}
}
}
POM
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.5.2</version>
<relativePath /> <!-- lookup parent from repository -->
</parent>
<groupId>com.hello</groupId>
<artifactId>privet</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>privet</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>11</java.version>
<spring-cloud.version>2020.0.3</spring-cloud.version>
<start-class>com.hello.HelloTask</start-class>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-task</artifactId>
</dependency>
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-configuration-processor</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>${spring-cloud.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-resources-plugin</artifactId>
<version>3.1.0</version>
</plugin>
</plugins>
</build>
</project>
I run spring cloud data flow skipper 2.8.1
I run spring cloud data flow server 2.8.1, obviously launches h2
Start Embedded H2
2021-06-28 19:08:43.967 INFO 95256 --- [ main] o.s.c.d.s.config.web.WebConfiguration : Starting H2 Server with URL: jdbc:h2:tcp://localhost:19092/mem:dataflow
I build the app, and in the UI - import the app, create a task, start the task and I get the dreaded....
org.springframework.context.ApplicationContextException: Failed to start bean 'taskLifecycleListener'; nested exception is java.lang.IllegalArgumentException: Invalid TaskExecution, ID 7 not found
at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:181) ~[spring-context-5.3.8.jar!/:5.3.8]
Any suggestions?

Answer 1

Spring Cloud Data Flow and your Spring Cloud Task app need to access the same database. Your pom.xml suggests that your SCT app is using an embedded H2 database that only itself can access.
Your app needs the driver for the shared database on the classpath. Please also have a look at the official documentation: https://docs.spring.io/spring-cloud-dataflow/docs/2.8.1/reference/htmlsingle/#spring-cloud-dataflow-register-task-apps
The task execution with its id is created by Data Flow before launching the app. When the app starts, it expects to find a task execution with the given id in the database that it's connected to.
If you start your app stand alone from the command line, it should work fine, as it then does not expect that the task execution is already created in its database.