Listing and Reading all the files in a Managed Folder

SuhasChinku
Level 2
Listing and Reading all the files in a Managed Folder

Hi All,

Can you help me in reading all the files present in a HDFS managed folder based on certain criteria/Pattern and writing the files into a different HDFS managed folder.

Attaching the problem statment. Please help.

Dataiku_Problem_statment.JPG

 Thanks in advance. 

 

 

 

 

 

 

 

5 Replies
ATsao
Dataiker
Dataiker

Hi SuhasChinku,

One option would be to use a Python recipe to read in the inputs of this HDFS managed folder, filter on the file names (using regex), and then copying over the files accordingly to the appropriate output managed folders by using the read/write APIs

import dataiku
import re

# Read inputs and managed folders. Make sure to use the appropriate managed folder IDs. 
input_folder = dataiku.Folder("INPUT_MANAGED_FOLDER_ID")
paths = input_folder.list_paths_in_partition()
output_folder1 = dataiku.Folder("OUTPUT_MANAGED_FOLDER1_ID")
output_folder2 = dataiku.Folder("OUTPUT_MANAGED_FOLDER2_ID")

# Iterate through files, check if they fit certain regex condition, and write them to output managed folders accordingly.
x=0
for paths[x] in paths:
    # Check if file starts with "/File_" and, if so, copy the file to the first output managed folder. Replace with appropriate regex as needed.
    if re.match(r"/[F|f]ile_\d+", paths[x]):
        with input_folder.get_download_stream(paths[x]) as f:
            data = f.read()
        with output_folder1.get_writer(paths[x]) as w:
            w.write(data)
    # Check if file starts with "/Input_file_" and, if so, copy the file to the second output managed folder. Replace with appropriate regex as needed.
    if re.match(r"/[i|I]nput_file_\d+", paths[x]):
        with input_folder.get_download_stream(paths[x]) as f:
            data = f.read()
        with output_folder2.get_writer(paths[x]) as w:
            w.write(data)
x +=1

 

I hope that this helps!

Best,

Andrew

 

SuhasChinku
Level 2
Author

Hi Andrew @ATsao,

Solution works Pefect...!!!!! Thank you so much.. 🙂

jaalija
Level 1

Hi @ATsao ,

I have a similar problem but I want to zip a file to another folder instead of just copying. Do you know how can i do this?

I was trying this to find the zip file from a specific month from a defined variable:

x=0
for paths[x] in paths:
if fnmatch.fnmatch(paths[x], '*' + (dataiku.get_custom_variables()["v_mth"]) + '.zip'):
     with input_folder.get_download_stream(paths[x]) as f:
          with zipfile.ZipFile(f.read(), "r") as zip_ref:
               zip_ref.extractall(output_folder)
x +=1

but I get the following error:

Job failed: Error in Python process: At line 48: <class 'AttributeError'>: 'bytes' object has no attribute 'seek'

 

Thank you very much!

0 Kudos
dima_naboka
Dataiker
Dataiker

Hi SuhasChinku,

As an alternative, you can utilize internal "files from folder" dataset to filter your files with regex

Screenshot 2020-07-07 at 09.12.10.pngScreenshot 2020-07-07 at 09.12.49.pngScreenshot 2020-07-07 at 09.12.36.png

Such approach would not use managed folder as output though. Generally speaking, it is not as flexible as Python code but could be useful if you prefer visual recipes over code recipes.

SuhasChinku
Level 2
Author

@dima_naboka ,

Thanks for your solution as well..:-) I was not aware of this .. I will leverage this idea..

A banner prompting to get Dataiku DSS
Public