Error handling enhancement: StringIndexOutOfBoundsException when executing task in k8s for malformed task arguments

[guoyiang]

Description:
When executing a task (POST tasks/executions), if arguments has an extra space at the end, spring cloud dataflow may throw a StringIndexOutOfBoundsException. Server will respond with status code 500 and payload:

{"_embedded":{"errors":[{"message":"String index out of range: -1","logref":"StringIndexOutOfBoundsException","_links":{"self":{"href":"/"}}}]}}%

The stacktrace on spring cloud dataflow:

2021-07-09 14:46:43.043 ERROR 1 --- [nio-8080-exec-3] o.s.c.d.s.k.KubernetesTaskLauncher       : String index out of range: -1

java.lang.StringIndexOutOfBoundsException: String index out of range: -1
        at java.lang.String.substring(String.java:1967)
        at org.springframework.cloud.deployer.spi.kubernetes.DefaultContainerFactory.lambda$createCommandArgs$0(DefaultContainerFactory.java:277)
        at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193)
        at java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1384)
        at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:482)
        at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:472)
        at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708)
        at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
        at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:566)
        at org.springframework.cloud.deployer.spi.kubernetes.DefaultContainerFactory.createCommandArgs(DefaultContainerFactory.java:278)
        at org.springframework.cloud.deployer.spi.kubernetes.DefaultContainerFactory.create(DefaultContainerFactory.java:102)
        at org.springframework.cloud.deployer.spi.kubernetes.AbstractKubernetesDeployer.createPodSpec(AbstractKubernetesDeployer.java:201)
        at org.springframework.cloud.deployer.spi.kubernetes.KubernetesTaskLauncher.launch(KubernetesTaskLauncher.java:238)
        at org.springframework.cloud.deployer.spi.kubernetes.KubernetesTaskLauncher.launch(KubernetesTaskLauncher.java:120)

Release versions:

{
  "versions": {
    "implementation": {
      "name": "spring-cloud-dataflow-server",
      "version": "2.7.1"
    },
    "core": {
      "name": "Spring Cloud Data Flow Core",
      "version": "2.7.1"
    },
    "dashboard": {
      "name": "Spring Cloud Dataflow UI",
      "version": "3.0.1"
    },
    "shell": {
      "name": "Spring Cloud Data Flow Shell",
      "version": "2.7.1",
      "url": "https://repo1.maven.org/maven2/org/springframework/cloud/spring-cloud-dataflow-shell/2.7.1/spring-cloud-dataflow-shell-2.7.1.jar"
    }
  },
  "features": {
    "streams": false,
    "tasks": true,
    "schedules": true,
    "monitoringDashboardType": "NONE"
  },
  "runtimeEnvironment": {
    "appDeployer": {
      "deployerImplementationVersion": null,
      "deployerName": null,
      "deployerSpiVersion": null,
      "javaVersion": null,
      "platformApiVersion": null,
      "platformClientVersion": null,
      "platformHostVersion": null,
      "platformSpecificInfo": {},
      "platformType": null,
      "springBootVersion": null,
      "springVersion": null
    },
    "taskLaunchers": [
      {
        "deployerImplementationVersion": "2.5.1",
        "deployerName": "KubernetesTaskLauncher",
        "deployerSpiVersion": "2.5.1",
        "javaVersion": "1.8.0_282",
        "platformApiVersion": "v1",
        "platformClientVersion": "unknown",
        "platformHostVersion": "unknown",
        "platformSpecificInfo": {
          "namespace": "dev",
          "master-url": "https://192.168.0.1:443/"
        },
        "platformType": "Kubernetes",
        "springBootVersion": "2.3.7.RELEASE",
        "springVersion": "5.2.12.RELEASE"
      }
    ]
  },
  "monitoringDashboardInfo": {
    "url": "",
    "source": "default-scdf-source",
    "refreshInterval": 15
  },
  "security": {
    "isAuthentication": false,
    "isAuthenticated": false,
    "username": null,
    "roles": []
  }
}

Steps to reproduce:

1. Setup a task app & task definition in spring cloud dataflow on kubernetes platform
2. Execute a task by calling API with a malformed argument, like the one below. Note the extra %20 at the end of arguments query param.

curl -X POST 'http://localhost:9393/tasks/executions?name=test&arguments=--a=b%20--c=d%20' -H 'Content-Type: application/json' 

Additional context:
It is caused when handling arguments in k8s deployer. It splits the arguments using space and then separate key/value using =. However the code doesn't handle the case when = is not present in each argument. Not too sure about the best approach to handle it, should we ignore such arguments, or return a validation error.
Though it's a caused by bad API integration, it would be great if a better message can be returned. It's not easy to figure out the cause without looking into stacktrace & source code.

Thanks for supporting it!

[sabbyanandan]

Thanks for the thorough write-up, @guoyiang. If you've cycles, please feel free to submit a PR to gracefully handle this workflow. We can pair to get this handled and bring it to the desired state.

[cppwfs]

This issue is resolved via 2.10. Please retest. Thank you for reporting!