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<@ULVA73B9P> we are currently using the `prefect.f...
# ask-marvin
s
@Marvin we are currently using the 
prefect.filesystems.S3
package and 
S3.load('BLOCK')
. We would like to move to 
prefect_aws.S3
what method should I be using to replace 
load
?
m
There isn't a direct 
load
method in the 
prefect_aws.S3Bucket
class, but you can achieve similar functionality using the 
S3Bucket.load()
method from Prefect. Here's a brief guide on how to transition: 1. Migrating from 
prefect.filesystems.S3
to `prefect_aws.S3Bucket`: - Old: 
prefect.filesystems.S3.load('BLOCK')
- New: 
prefect_aws.S3Bucket.load('BLOCK')
2. Example Usage:
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python
from prefect_aws.s3 import S3Bucket

# Load the S3 bucket block
s3_bucket = S3Bucket.load("BLOCK")

# You can then use methods like `s3_bucket.write_path`, `s3_bucket.read_path` to interact with the S3 bucket
Here are some relevant links for more detailed information: - prefect_aws S3Bucket Documentation If you encounter any issues, please refer to the documentation or open a new issue on GitHub.
n
hi @Scott Pedersen - they are both blocks so they should both have 
load
methods ie, you shouldnt need to are you seeing something unexpected?
s
Hey @Nate, when I was looking at the documentation for 
prefect_aws.S3Bucket
I couldn't see a 
load
method in the table of contents, however, further down in the examples I can see 
S3Bucket.load()
being used
n
aha. i see, we're probably just showing methods specific to the 
S3Bucket
subclass there, as opposed to all methods that come for free by virtue of it being a 
Block
👍 1
s
Just to clarify, is it just a package change and we can continue to use 
load
they way we are currently using it? We pass the s3_bucket to 
Flow.from_source
n
exactly! that should be right
thank you 1
s
Hi @Marvin I have set up an S3 Bucket block with the correct Bucket Name and Bucket Folder i.e. bucket-name/folder-name The assumed role used for running flows on K8s has access to the bucket and folders. I am using 
from prefect_aws.S3 import S3Bucket
package and 
S3Bucket.load("name-of-block")
to load the contents. I have the 
flow.from_source(s3_block, {path}/flow.py:my_flow)
. I am receiving the following error
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prefect.exceptions.ScriptError: Script at '/tmp/tmpiekdqty5/s3-bucket-name-of-block/flow.py' encountered an exception: FileNotFoundError(2, 'No such file or directory')"
The path looks correct except I would have thought that the 
/tmp/tmpiekdqty5/s3-bucket-name-of-block
would be the initial path to the flow folder. Can you offer any advise on how to fix this?
m
It seems like there isn't a direct match for your specific issue in the repositories or additional documentation found, but I have a few recommendations to help troubleshoot and potentially solve your problem. 1. Verify Path Setup: Ensure that the path you are passing is correctly formatted and exists in the specified S3 bucket. 2. Check Permission: Double-check that the assumed role you're using indeed has the necessary permissions to access the bucket and folder. Sometimes, the assumed roles might miss specific permissions like 
s3:ListBucket
or 
s3:GetObject
. 3. Intermediate Directory Structure: Sometimes, interim paths might not be correctly laid out. Try printing the available directories and checking the exact structure of the temporary directory. 4. Example Usage: Here's a refined example that ensures the correct loading and access to the S3 bucket contents:
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python
   from prefect_aws.s3 import S3Bucket
   from prefect import flow

   @flow
   def load_flow():
       s3_bucket = S3Bucket.load("name-of-block")
       local_path = s3_bucket.download("folder-name/flow.py")
       print(f"Flow path: {local_path}")
   
   load_flow()
5. Temporary Directory Handling: Ensure that the flow execution environment has the necessary permissions to write to the temporary directory 
/tmp/
. If the issue persists, consider opening a new issue on the Prefect GitHub repository. Provide details about your configuration, the exact error message, and any relevant logs. For more detailed information, refer to the Prefect AWS S3 Documentation.
n
hi @Scott Pedersen,can you share block of code where you do this?
I am using 
from prefect_aws.S3 import S3Bucket
package and 
S3Bucket.load("name-of-block")
to load the contents. I have the 
flow.from_source(s3_block, {path}/flow.py:my_flow)
s
Sure
workspace_settings.flow_storage_block = S3 Bucket Block Name
n
hrm im not sure as a sanity check, maybe we could print 
s3_storage
before you pass it into 
from_source
? its very odd to me that we're seeing the block name in this path
/tmp/tmpiekdqty5/s3-bucket-name-of-block/flow.py
prefect version
would also be helpful
s
The prefect version we are currently using is 2.16.6
What I'll do is set it back to the original S3 block and S3.load method and print that out and see what the differences are between to the two.
@Nate I logged the 
S3Bucket.load
and 
S3.load
objects that are returned and they both look similar except for the additions in 
S3Bucket
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S3Bucket(
	bucket_name='bucket-name', 
	credentials=AwsCredentials(
		aws_access_key_id=None, 
		aws_secret_access_key=None, 
		aws_session_token=None, 
		profile_name=None, 
		region_name=None, 
		aws_client_parameters=AwsClientParameters(
			api_version=None, 
			use_ssl=True, 
			verify=True, 
			verify_cert_path=None, 
			endpoint_url=None, 
			config=None)
	), 
	bucket_folder='bucket-name/flows'
)


S3(bucket_path='bucket-name/flows', 
	aws_access_key_id=None, 
	aws_secret_access_key=None
)
@Marvin for an S3 Bucket block if I have a bucket called my-bucket and a folder called my-folder what should the bucket_folder be populated with? Should it be my-bucket/my-folder or just my-folder?
m
The correct value for the 
bucket_folder
in your 
S3Bucket
block configuration should be just the folder name within the bucket. So if your bucket is called 
my-bucket
and the folder you want to use is 
my-folder
, you should set 
bucket_folder
to 
my-folder
. Here's the correct configuration syntax:
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bucket_name: my-bucket
bucket_folder: my-folder
For more details, you can refer to the relevant Prefect AWS S3 Documentation.
s
@Marvin when I use 
Flow.from_source
and I use what is returned from calling 
S3Bucket.load
so my call looks like 
my_flow.from_source(s3_storage, path/to/flow.py:my_flow)
does the 
path/to/flow.py:my_flow
need to include the 
bucket-name
and 
bucket-folder
?
m
The documentation does not explicitly detail the format for paths when using 
Flow.from_source
with 
S3Bucket
. However, based on common practice and the structure typically used in similar operations, here's how you should structure the path: 1. Without 
bucket-name
and 
bucket-folder
: - When you call 
S3Bucket.load
, it should already be aware of the 
bucket_name
and 
bucket_folder
. Therefore, the path provided to 
Flow.from_source
should be relative to the 
bucket_folder
. Example:
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python
   from prefect_aws.s3 import S3Bucket
   from prefect import flow

   @flow
   def my_flow():
       pass

   # Load the S3 bucket block
   s3_storage = S3Bucket.load("name-of-block")

   # Call from_source with a path relative to the bucket folder
   my_flow.from_source(s3_storage, "path/to/flow.py:my_flow")
2. Alternative Scenario: - If you face issues, another approach to ensure correctness would involve giving the full S3 path. Example:
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python
   my_flow.from_source(s3_storage, "my-bucket/my-folder/path/to/flow.py:my_flow")
However, the preferred practice should be aligning with the block's inherent configuration. Here’s an important point from the relevant Prefect AWS S3 Documentation: - The 
bucket_folder
should only contain the folder inside the bucket, e.g., 
my-folder
. - 
Flow.from_source
path should then be relative to this 
bucket_folder
, e.g., 
path/to/flow.py:my_flow
. If these suggestions don't resolve the issue, I recommend reaching out to the Prefect community or consulting the Prefect documentation further to ensure clarity.
s
Hi @Marvin that was my understand that the 
/path/to/flow.py:my_flow
would be relative to the 
bucket-name/bucket-folder
.
m
Given your understanding, you are correct that the path specified in 
Flow.from_source
should be relative to the 
bucket_folder
defined in the 
S3Bucket
block. Here's how you can structure it: 1. Define the 
bucket_folder
properly: - Ensure your 
S3Bucket
block has the 
bucket_folder
set correctly (just the folder name within the bucket). Example:
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python
from prefect_aws.s3 import S3Bucket

s3_bucket = S3Bucket(
    bucket_name="my-bucket",
    bucket_folder="my-folder",
    credentials=<Your AWSCredentials Block>
)
s3_bucket.save("name-of-block")
2. Load the flow from the S3 bucket: - When specifying the path in 
Flow.from_source
, it should be relative to the 
bucket_folder
. Example:
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python
from prefect_aws.s3 import S3Bucket
from prefect import flow

@flow
def my_flow():
    pass

# Load the S3 bucket block
s3_storage = S3Bucket.load("name-of-block")

# Call from_source with a path relative to the bucket folder
my_flow.from_source(s3_storage, "path/to/flow.py:my_flow")
### Detailed Steps: 1. Define your S3Bucket block: Make sure the 
bucket_name
and 
bucket_folder
are correctly set when you create and save the block. 2. Load the S3Bucket: Use 
S3Bucket.load("name-of-block")
to retrieve the block. 3. Set the path relative to 
bucket_folder
: Provide the path in 
Flow.from_source
relative to the 
bucket_folder
. Here’s a concrete example: - S3 Bucket: 
my-bucket
- Folder inside the bucket (
bucket_folder
): 
my-folder
- Path to your flow file inside the bucket folder: 
path/to/flow.py
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python
# Structure the path as relative to the bucket_folder
from prefect_aws.s3 import S3Bucket
from prefect import flow

@flow
def example_flow():
    pass

s3_bucket = S3Bucket.load("name-of-block")

# Assuming the actual S3 structure is: my-bucket/my-folder/path/to/flow.py
example_flow.from_source(s3_bucket, "path/to/flow.py:example_flow")
In case the issue persists, consider verifying the contents of your S3 bucket directly to ensure the paths are correct, and that the role assumed has all the necessary permissions to access the files. If any issues remain, check the structure to confirm it aligns with the expected layout.
s
@Marvin we use an assumed role that runs the flow and has access to the underlying S3 bucket so in this case the 
credentials=<Your AWSCredentials Block>
wouldn't be required. Would it be OK to leave this out?
m
Yes, if you are using an assumed role to run the flow and it has the necessary access to the S3 bucket, you can leave out the 
credentials
parameter when setting up your 
S3Bucket
block. Prefect should use the role that the process is running under to access the S3 bucket. Here's how you can set up and use the 
S3Bucket
block without specifying credentials: 1. Define the 
S3Bucket
block without credentials:
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python
from prefect_aws.s3 import S3Bucket

# Define the S3 bucket block
s3_bucket = S3Bucket(
    bucket_name="my-bucket",
    bucket_folder="my-folder"
)

# Save the block
s3_bucket.save("name-of-block")
2. Load the S3Bucket block and use 
Flow.from_source
:
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python
from prefect_aws.s3 import S3Bucket
from prefect import flow

@flow
def example_flow():
    pass

# Load the S3 bucket block
s3_bucket = S3Bucket.load("name-of-block")

# Specify the path relative to the bucket folder
example_flow.from_source(s3_bucket, "path/to/flow.py:example_flow")
### Additional Tips: - Ensure Permissions: Make sure that the assumed role has sufficient permissions (including 
s3:GetObject
, 
s3:ListBucket
, etc.) for the S3 bucket. - Validate Path: Double-check the S3 bucket structure and ensure the path specified (
path/to/flow.py:example_flow
) correctly maps to the location within 
my-folder
. This approach adheres to your setup and leverages the role's inherent permissions to access the S3 bucket without needing additional credentials. If everything is configured properly, this should resolve the file access issues you were encountering.
s
@Marvin when I call 
Flow.deploy()
from my code what is the workflow that is followed within Prefect?
m
When you call 
Flow.deploy()
within Prefect, the workflow generally follows these steps: 1. Serialization of Flow: - The flow is serialized into a format that can be stored and later executed. This serialization includes the flow's code, configuration, dependencies, and metadata. 2. Storage of Flow: - The serialized flow is stored in the specified storage backend (e.g., S3, Docker, Kubernetes, etc.). The storage backend defined in the flow is responsible for housing the flow's code and any associated files. 3. Registration as a Deployment: - The flow is registered as a deployment within the Prefect API (either Prefect Cloud or a self-hosted Prefect server). This includes creating a deployment entry that tracks the flow's configuration, schedules, parameters, and storage details. 4. Creation of Work Pool or Queue: - The deployment may be associated with a work pool or queue. This is where it waits for a worker to pick it up and execute a flow run. Different infrastructure backends (like Docker, Kubernetes, serverless cloud options) determine how and where these flows run. 5. Polling and Execution by Workers: - Workers, which could be running in different environments (e.g., local processes, Docker containers, Kubernetes jobs), poll the work pool or queue for new flow runs. Once a new flow run is identified, the worker retrieves the flow from storage, initializes the environment, and executes the flow. Here is a high-level visualization of this process:
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plaintext
Flow Code -> Serialization -> Storage Backend (e.g., S3, Docker) -> Registration as Deployment -> Work Pool/Queue -> Worker Polling -> Flow Run Execution
For more detailed guidance, including how to set up and manage deployments, refer to these documentation pages: - Prefect Deployment Guide - Prefect Deployments Tutorial These docs provide comprehensive insights into the deployment process, configurations, and best practices for setting up your flows in Prefect.
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