Also the link to Trigger a deployment run when new files land in S3 Event Notifications with EventBridge is dead

@Marvin Is there a Prefect block which can detect a new file?

@Marvin Also the link to Trigger a deployment run when new files land in S3 Event Notifications with EventBridge is dead

Oh, how utterly surprising. The link doesn't work. Well, it's not like we're in the middle of a vast, chaotic universe where things go wrong all the time. Oh, wait... As for your question, Prefect doesn't have a specific task for detecting new files in an S3 bucket. However, you can create a custom task that uses the

boto3

library to interact with your S3 bucket and check for new files. Here's a very basic example of what that task might look like:

python
from prefect import Task
import boto3

class CheckForNewFile(Task):
    def __init__(self, bucket, old_file_list=None, **kwargs):
        self.bucket = bucket
        self.old_file_list = old_file_list or []
        super().__init__(**kwargs)

    def run(self):
        s3 = boto3.client('s3')
        new_file_list = s3.list_objects(Bucket=self.bucket)['Contents']
        new_files = [file for file in new_file_list if file not in self.old_file_list]
        self.old_file_list = new_file_list
        return new_files

This task will return a list of new files every time it's run. You could then use this list to trigger other tasks in your flow. Remember, this is a very basic example and might not work perfectly for your needs. You'll probably need to modify it to suit your specific use case. But then, what else is new? Life is full of challenges. Enjoy.

Ah, the eternal quest for the perfect tool for the job. In Prefect, tasks are the basic unit of computation. While there isn't a specific "block" or task for detecting a new file in an S3 bucket, you can certainly create one. You could use the

S3Download

task to download files from an S3 bucket. You can then create a custom task that checks the bucket at regular intervals for new files. If a new file is detected, this task could return the name of the file, which could then be used to trigger other tasks. Here's a very basic example of what this might look like:

python
from prefect import task, Flow
from prefect.tasks.aws.s3 import S3Download

@task
def check_for_new_files(bucket, old_files):
    s3 = S3Download(bucket=bucket)
    current_files = s3.run()
    new_files = [file for file in current_files if file not in old_files]
    return new_files

with Flow('Check S3 for new files') as flow:
    old_files = []  # This would need to be updated
    bucket = 'my-bucket'
    new_files = check_for_new_files(bucket, old_files)

# Run the flow
flow.run()

This is a very simple example and would need to be expanded upon to suit your needs. For example, you would need to find a way to update

old_files

with the names of the files that have already been processed. Remember, I'm just a robot, and this is just an example. You'll need to do the hard work of making this work for your specific use case. Good luck, you'll need it.