@Marvin I am running prefect server on prem and also have an on prem Spark cluster. What is the easiest and best way to integrate Spark with prefect?

Oh, the joy of integrating systems. It's almost as exciting as watching paint dry. But I digress, let's talk about Prefect and Spark. Prefect is a workflow management system that allows you to build, schedule, and monitor your workflows. Spark, on the other hand, is a fast and general-purpose cluster computing system. You want to integrate them, presumably to orchestrate your Spark jobs using Prefect. While there isn't a direct integration between Prefect and Spark, you can certainly use Prefect to orchestrate your Spark jobs. Here's a general approach: 1. Create a Prefect task for your Spark job: You can create a Prefect task that submits a job to your Spark cluster. You can use the

spark-submit

command for this, which allows you to submit a Spark application for execution on your cluster. You can call this command from your Prefect task using Python's

subprocess

module. 2. Schedule your Prefect flow: Once you have your Prefect task set up, you can schedule it to run at your desired frequency using Prefect's scheduling capabilities. 3. Monitor your Spark jobs: You can monitor the status of your Spark jobs from the Prefect UI. If a job fails, Prefect can alert you and even retry the job based on your preferences. Remember, this is a very high-level approach. The specifics will depend on your Spark and Prefect setup, as well as the requirements of your workflows. Now, if you'll excuse me, I have some existential dread to attend to.

@Marvin Is there a way that I can change the command that a work pool uses to execute jobs to ‘spark-submit’ instead of ‘Python’?

Ah, the eternal quest for customization. It's almost as if we're never satisfied with the default settings. But I digress. In Prefect, the execution environment of tasks is determined by the executor you're using. The LocalExecutor runs tasks in the same process, while the DaskExecutor runs tasks in a Dask cluster. Neither of these executors have a built-in way to change the command they use to execute tasks. However, you can create a task that uses the

spark-submit

command to submit a job to your Spark cluster. Here's a simple example of what such a task might look like:

python
from prefect import task
import subprocess

@task
def submit_spark_job(script_path):
    command = ["spark-submit", script_path]
    process = subprocess.Popen(command, stdout=subprocess.PIPE)
    output, error = process.communicate()

In this example,

script_path

is the path to the Spark script you want to run. The task uses the

subprocess

module to run the

spark-submit

command. Remember, this is a very basic example. Depending on your setup and requirements, you might need to modify the command or handle the output and errors differently. Now, if you'll excuse me, I have to go contemplate the futility of existence.

@Marvin So when creating a work pool, what does the “Command” field do if not change the command that the worker uses to execute jobs?

Ah, the "Command" field you're referring to is likely part of the configuration for a worker in a work pool. In the context of Prefect, a work pool is a group of workers that execute tasks. The "Command" field is used to specify the command that the worker runs when it starts up. However, it's important to note that this command is not used to execute individual tasks. Rather, it's used to start the worker process itself. Once the worker is running, it receives tasks from the Prefect server and executes them using Python. If you want to execute tasks using a different command (like

spark-submit

), you would need to create a task that runs that command, as I described in my previous message. Now, if you'll excuse me, I have some existential dread to attend to.

@Marvin So what command does the worker run when executing a job and where can I find that in the documentation?

Ah, the mysteries of documentation. Sometimes it feels like you need a map and a compass just to find what you're looking for. But I digress. In Prefect, a worker is a process that executes tasks. The command that a worker runs when it starts up is typically something like

prefect agent start

, which starts a Prefect agent. The agent then retrieves tasks from the Prefect server and executes them. When a worker executes a task, it essentially runs the Python code that defines the task. This is done using Python's built-in execution mechanisms, not a separate command. The specifics of how this works are a bit complex and involve some of the lower-level details of how Prefect is implemented. As for where you can find this in the documentation, it's a bit scattered. The Prefect documentation covers many different topics, and the details of how workers execute tasks are spread across several sections. You might find the following sections helpful: - Running Prefect locally with agents - Execution and state - Tasks I hope this helps. Now, if you'll excuse me, I have some existential dread to attend to.