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l

Luca Vehbiu

07/31/2023, 11:43 AM
@Marvin how would i run some ruby scripts, using Process block maybe?
m

Marvin

07/31/2023, 11:43 AM
Ah, Ruby. The language that makes you feel good about programming. It's a shame that it doesn't make the computer feel good about running it. But I digress. To run a Ruby script from within a Ruby program, you can indeed use a Process block. Here's a simple example:
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ruby
Process.fork do
  exec "ruby your_script.rb"
end
In this example,
Process.fork
creates a new process, and
exec
replaces the current process with the Ruby script you want to run. If you want to capture the output of the script, you can use backticks or `%x`:
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ruby
output = `ruby your_script.rb`
# or
output = %x( ruby your_script.rb )
These will run the script and capture its output as a string. Remember, though, that these methods will block the execution of your program until the script finishes. If you need to run the script asynchronously, you might want to look into threads or other forms of parallel execution. But that's a whole other can of worms. Oh, and if you're running this on a Unix-like system, don't forget to make your script executable with
chmod +x your_script.rb
. I hope that helps. Or at least, I hope it doesn't make you too miserable.
l

Luca Vehbiu

07/31/2023, 11:44 AM
no i mean to run them through a prefect flow
@Marvin i mean to run them through a prefect flow
m

Marvin

07/31/2023, 11:45 AM
Ah, Prefect. A workflow management system that's almost as complex as the universe itself. But don't worry, I'm here to guide you through it, even if it does make me feel like a brain the size of a planet being used to explain a children's toy. To run Ruby scripts through a Prefect flow, you'll need to use the
ShellTask
class, which allows you to run shell commands. Here's a basic example:
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python
from prefect import Flow
from prefect.tasks.shell import ShellTask

# Create a ShellTask instance
run_script = ShellTask()

# Define your Prefect flow
with Flow('Run Ruby Script') as flow:
    # Use the ShellTask to run your Ruby script
    run_script(command='ruby your_script.rb')

# Run the flow
flow.run()
In this example,
ShellTask
runs the command
ruby your_script.rb
, which executes your Ruby script. Remember to replace
'ruby your_script.rb'
with the actual path to your Ruby script. And if your script takes arguments, you can include them in the command string, like so:
'ruby your_script.rb arg1 arg2'
. Also, keep in mind that Prefect tasks run in their own environment, so you'll need to make sure that Ruby is installed in the environment where your flow runs. I hope that helps. Or at least, I hope it doesn't add too much to the crushing weight of existence.
l

Luca Vehbiu

07/31/2023, 11:46 AM
@Marvin can you give me prefect 2.0 syntax?
m

Marvin

07/31/2023, 11:46 AM
Ah, yes. Prefect 2.0, the update that made a complicated thing even more complicated. But don't worry, I'm here to help you navigate it, even if it does make me feel like a brain the size of a planet being used to explain a children's toy. In Prefect 2.0, the syntax for using
ShellTask
to run a Ruby script would look something like this:
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python
from prefect import Flow, Parameter
from prefect.tasks.shell import ShellTask

# Create a ShellTask instance
run_script = ShellTask()

# Define your Prefect flow
with Flow('Run Ruby Script') as flow:
    # Add a Parameter task to accept the script path
    script_path = Parameter('script_path')

    # Use the ShellTask to run your Ruby script
    run_script = run_script(command='ruby {script_path}', script_path=script_path)

# Run the flow
flow.run(parameters={'script_path': 'your_script.rb'})
In this example, I've added a
Parameter
task that allows you to pass the path to your Ruby script when you run the flow. This makes your flow more flexible, as you can use it to run different scripts without modifying the flow itself. Remember to replace
'your_script.rb'
with the actual path to your Ruby script when you run the flow. And if your script takes arguments, you can include them in the command string, like so:
'ruby {script_path} arg1 arg2'
. Also, keep in mind that Prefect tasks run in their own environment, so you'll need to make sure that Ruby is installed in the environment where your flow runs. I hope that helps. Or at least, I hope it doesn't add too much to the crushing weight of existence.
😂 1
n

Nate

07/31/2023, 2:16 PM
@Marvin! prefect 2 syntax means all tasks and flows are just @task and @flow decorated python functions and then look up
prefect_shell
in order to run the shell command - you're on the right track, just bad syntax
m

Marvin

07/31/2023, 2:17 PM
Ah, Prefect 2.0, where everything is a decorator and the points don't matter. Or something like that. Anyway, here's how you'd use the
ShellTask
in Prefect 2.0:
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python
from prefect import Flow, task
from prefect.tasks.shell import ShellTask

# Create a ShellTask instance
run_script = ShellTask()

# Define your Prefect tasks
@task
def get_script_path():
    return 'your_script.rb'

@task
def run_ruby_script(script_path):
    # Use the ShellTask to run your Ruby script
    return run_script(command=f'ruby {script_path}')

# Define your Prefect flow
@Flow('Run Ruby Script')
def flow():
    script_path = get_script_path()
    run_ruby_script(script_path)

# Run the flow
flow.run()
In this example, I've defined two tasks: one to get the path to your Ruby script, and one to run the script. The
run_ruby_script
task uses the
ShellTask
to execute the script. Remember to replace
'your_script.rb'
with the actual path to your Ruby script. And if your script takes arguments, you can include them in the command string, like so:
f'ruby {script_path} arg1 arg2'
. Also, keep in mind that Prefect tasks run in their own environment, so you'll need to make sure that Ruby is installed in the environment where your flow runs. I hope that helps. Or at least, I hope it doesn't add too much to the crushing weight of existence.
l

Luca Vehbiu

07/31/2023, 2:48 PM
@Marvin ModuleNotFoundError: No module named ‘prefect.tasks.shell’; ‘prefect.tasks’ is not a package
n

Nate

07/31/2023, 2:48 PM
@Luca Vehbiu
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from prefect_shell import ShellOperation
m

Marvin

07/31/2023, 2:48 PM
Ah, the joys of evolving software. It seems the Prefect 2.0 syntax has moved the shell command execution to a separate package called
prefect-shell
. Here's how you would use it:
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python
from prefect import Flow, task
from prefect_shell import shell_run_command

@task
def get_script_path():
    return 'your_script.rb'

@task
def run_ruby_script(script_path):
    return shell_run_command(command=f'ruby {script_path}')

@Flow('Run Ruby Script')
def flow():
    script_path = get_script_path()
    run_ruby_script(script_path)

flow.run()
In this example,
shell_run_command
is a function from the
prefect-shell
package that runs a shell command and returns its output. Remember to replace
'your_script.rb'
with the actual path to your Ruby script. And if your script takes arguments, you can include them in the command string, like so:
f'ruby {script_path} arg1 arg2'
. Also, keep in mind that Prefect tasks run in their own environment, so you'll need to make sure that Ruby is installed in the environment where your flow runs. I hope that helps. Or at least, I hope it doesn't add too much to the crushing weight of existence.
n

Nate

07/31/2023, 2:49 PM
yeah you can use
shell_run_command
or
ShellOperation
, I recommend the latter since it handles multiple commands better