Read Parquet file stored in S3 with AWS Lambda (Python 3) - python

I am trying to load, process and write Parquet files in S3 with AWS Lambda. My testing / deployment process is:
https://github.com/lambci/docker-lambda as a container to mock the Amazon environment, because of the native libraries that need to be installed (numpy amongst others).
This procedure to generate a zip file: http://docs.aws.amazon.com/lambda/latest/dg/with-s3-example-deployment-pkg.html#with-s3-example-deployment-pkg-python
Add a test python function to the zip, send it to S3, update the lambda and test it
It seems that there are two possible approaches, which both work locally to the docker container:
fastparquet with s3fs: Unfortunately the unzipped size of the package is bigger than 256MB and therefore I can't update the Lambda code with it.
pyarrow with s3fs: I followed https://github.com/apache/arrow/pull/916 and when executed with the lambda function I get either:
If I prefix the URI with S3 or S3N (as in the code example): In the Lambda environment OSError: Passed non-file path: s3://mybucket/path/to/myfile in pyarrow/parquet.py, line 848. Locally I get IndexError: list index out of range in pyarrow/parquet.py, line 714
If I don't prefix the URI with S3 or S3N: It works locally (I can read the parquet data). In the Lambda environment, I get the same OSError: Passed non-file path: s3://mybucket/path/to/myfile in pyarrow/parquet.py, line 848.
My questions are :
why do I get a different result in my docker container than I do in the Lambda environment?
what is the proper way to give the URI?
is there an accepted way to read Parquet files in S3 through AWS Lambda?
Thanks!

AWS has a project (AWS Data Wrangler) that allows it with full Lambda Layers support.
In the Docs there is a step-by-step to do it.
Code example:
import awswrangler as wr
# Write
wr.s3.to_parquet(
dataframe=df,
path="s3://...",
dataset=True,
database="my_database", # Optional, only with you want it available on Athena/Glue Catalog
table="my_table",
partition_cols=["PARTITION_COL_NAME"])
# READ
df = wr.s3.read_parquet(path="s3://...")
Reference

I was able to accomplish writing parquet files into S3 using fastparquet. It's a little tricky but my breakthrough came when I realized that to put together all the dependencies, I had to use the same exact Linux that Lambda is using.
Here's how I did it:
1. Spin up a EC2 instance using the Amazon Linux image that is used with Lambda
Source:
https://docs.aws.amazon.com/lambda/latest/dg/current-supported-versions.html
Linux image:
https://console.aws.amazon.com/ec2/v2/home#Images:visibility=public-images;search=amzn-ami-hvm-2017.03.1.20170812-x86_64-gp2
Note: you might need to install many packages and change python version to 3.6 as this Linux is not meant for development. Here's how I looked for packages:
sudo yum list | grep python3
I installed:
python36.x86_64
python36-devel.x86_64
python36-libs.x86_64
python36-pip.noarch
python36-setuptools.noarch
python36-tools.x86_64
2. Used the instructions from here to built a zip file with all of the dependencies that my script would use with dumping them all in a folder and the zipping them with this command:
mkdir parquet
cd parquet
pip install -t . fastparquet
pip install -t . (any other dependencies)
copy my python file in this folder
zip and upload into Lambda
Note: there are some constraints I had to work around: Lambda doesn't let you upload zip larger 50M and unzipped > 260M. If anyone knows a better way to get dependencies into Lambda, please do share.
Source:
Write parquet from AWS Kinesis firehose to AWS S3

This was an environment issue (Lambda in VPC not getting access to the bucket). Pyarrow is now working.
Hopefully the question itself will give a good-enough overview on how to make all that work.

One can also achieve this through the AWS sam cli and Docker (we'll explain this requirement later).
1.Create a directory and initialize sam
mkdir some_module_layer
cd some_module_layer
sam init
by typing the last command a series of three question would be prompted. One could choose the following series of answers (I'm considering working under Python3.7, but other options are possible).
1 - AWS Quick Start Templates
8 - Python 3.7
Project name [sam-app]: some_module_layer
1 - Hello World Example
2. Modify requirements.txt file
cd some_module_layer
vim hello_world/requirements.txt
this will open requirements.txt file on vim, on Windows you could type instead code hello_world/requirements.txt to edit the file on Visual Studio Code.
3. Add pyarrow to requirements.txt
Alongside pyarrow, it will work to include additionnaly pandas and s3fs. In this case including pandas will avoid it to not recognize pyarrow as an engine to read parquet files.
pandas
pyarrow
s3fs
4. Build with a container
Docker is required to use the option --use-container when running the sam build command. If it's the first time, it will pull the lambci/lambda:build-python3.7 Docker image.
sam build --use-container
rm .aws-sam/build/HelloWorldFunction/app.py
rm .aws-sam/build/HelloWorldFunction/__init__.py
rm .aws-sam/build/HelloWorldFunction/requirements.txt
notice that we're keeping only the python libraries.
5. Zip files
cp -r .aws-sam/build/HelloWorldFunction/ python/
zip -r some_module_layer.zip python/
On Windows, it would work to run Compress-Archive python/ some_module_layer.zip.
6. Upload zip file to AWS
The following link is useful for this.

Related

AWS Glue: passing additional Python modules to the job - ModuleNotFoundError

I'm trying to run a Glue job (version 4) to perform a simple data batch processing. I'm using additional python libraries that Glue environment doesn't provide with - translate and langdetect. Additionally, regardless of the Glue env provides with 'nltk' package, when I try to import it I keep receiving the error that dependencies are not found (e.g. regex._regex, _sqlite3).
I tried a few solutions to achieve my goal:
using --extra-py-files where I specified path to s3 bucket where I uploaded either:
.zip file that consists of translate and langdetect python packages
just a directory for already unzipped packages
packages itself in .whl format (along with its dependencies)
using --additional-python-modules where I specified path to s3 bucket where I uploaded:
packages itself in .whl format (along with its dependencies)
or just pinpoint which package has to be installed inside the glue env via pip3
using Docker
Additionally, I followed a few useful sources to overcome the issue of ModuleNotFoundError:
a) https://aws.amazon.com/premiumsupport/knowledge-center/glue-import-error-no-module-named/.
b) https://aws.amazon.com/premiumsupport/knowledge-center/glue-version2-external-python-libraries/
c) https://docs.aws.amazon.com/glue/latest/dg/aws-glue-programming-python-libraries.html
Also, I tried to play with the Glue versions 4 and 3 but haven't had luck. It seems like a bug. All permissions to read s3 bucket is granted to the glue role. The Python script version is the same as the libraries I'm trying to install - Python 3. To give you more clues, I manage glue resources via Terraform.
What did I do wrong?

Reducing Python zip size to use with AWS Lambda

I'm following this blog post to create a runtime environment using Docker for use with AWS Lambda. I'm creating a layer for using with Python 3.8:
docker run -v "$PWD":/var/task "lambci/lambda:build-python3.8" /bin/sh -c "pip install -r requirements.txt -t python/lib/python3.8/site-packages/; exit"
And then archiving the layer as zip: zip -9 -r mylayer.zip python
All standard so far. The problem arises in the .zip size, which is > 250mb and so creates the following error in Lambda: Failed to create layer version: Unzipped size must be smaller than 262144000 bytes.
Here's my requirements.txt:
s3fs
scrapy
pandas
requests
I'm including s3fs since I get the following error when trying to save a parquet file to an S3 bucket using pandas: [ERROR] ImportError: Install s3fs to access S3. This problem is that including s3fs massively increases the layer size. Without s3fs the layer is < 200mb unzipped.
My most direct question would be: How can I reduce the layer size to < 250mb while still using Docker and keeping s3fs in my requirements.txt? I can't explain the 50mb+ difference, especially since s3fs < 100kb on PyPi.
Finally, for those questioning my use of Lambda with Scrapy: my scraper is trivial, and spinning up an EC2 instance would be overkill.
The key idea behind shrinking your layers is to identify what pip installs and what you can get rid off, usually manually.
In your case, since you are only slightly above the limit, I would get rid off pandas/tests. So before you create your zip layer, you can run the following in the layer's folder (mylayer from your past question):
rm -rvf python/lib/python3.8/site-packages/pandas/tests
This should trim your layer below the 262MB limit after unpacking. In my test it is now 244MB.
Alternatively, you can go over python folder manually, and start removing any other tests, documentations, examples, etc, that are not needed.
I can't explain the 50mb+ difference, especially since s3fs < 100kb on PyPi.
That's simple enough to explain. As expected, s3fs has internal dependencies on AWS libraries (botocore in this case). The good news is that boto3 is already included in AWS lambda (see this link for which libraries are available in lambda) therefore you can exclude botocore from your zipped dependencies and save up to ~50MB in total size.
See the above link for more info. The libraries you can safely remove from your zipped artifact file and still be able to run the code on an AWS lambda function running Python 3.8:
boto3
botocore
docutils
jmespath
pip
python-dateutil (generates the dateutil package)
s3transfer
setuptools
six (generates six.py)
urllib3 (if needed, bundled dependencies like chardet could also be removed)
You can also use a bash script to recursively get rid of the following (junk) directories that you don't need:
__pycache__
*.dist-info (example: certifi-2021.5.30.dist-info)
tests - Only possibly, but I can't confirm. If you do choose to recursively get rid of all tests folders, first check if anything breaks on lambda, since in rare cases such a package could be imported in code.
Do all this and you should easily save around ~60MB in zipped artifact size.

Lambda Won't Detect The Layer

I have a python3.8, and I created a new folder and installed pandas in it using
pip3 install pandas -t .
Next thing - zipped the folder (the zipped folder is 38Mb), and uploaded to s3.
Created a Layer and added the s3 path of zip file in it (also set the runtime env to python3.8 here)
Next I created a lambda function with python3.8 and test its skeleton first and it worked.
Added the layer to the lambda function and imported pandas. And now when I run the test, it does not detect pandas and gives me Module Not Found error.
What can I be doing wrong here?
Did you created a folder named python and put all the package files inside it? Also another supporting package Pytz is required to run panda in lambda. I use MAC OSX to create the zip file but the root folder needs to be named as "python".
The creation of the zip file is little bit lengthy to describe here, I suggest you to go through this document. Also naming convention is equally important. I think if you follow the document and create the zip file and upload it directly (or via S3) to create lambda layer then it will definitely work.

How to use AWS Lambda layer using Python?

I have a simple Lambda function which is using the numpy library,
I have set up a virtual environment in my local, and my code is able to fetch and use the library locally.
I tried to use AWS Lambda's layer, and zipped the venv folder and uploaded to the layer,
Then I attached the correct layer and version to my function,
But the function is not able to fetch the library
Following is the code which works fine on local -
import numpy as np
def main(event, context):
a = np.array([1, 2, 3])
print("Your numpy array:")
print(a)
Following is the venv structure which I zipped and uploaded -
I get the following error -
{
"errorMessage": "Unable to import module 'handler': No module named 'numpy'",
"errorType": "Runtime.ImportModuleError"
}
My Lambda deployment looks like this -
I'm trying to refer this -
https://towardsdatascience.com/introduction-to-amazon-lambda-layers-and-boto3-using-python3-39bd390add17
I've seen that a few libraries like numpy and pandas don't work in Lambda when installed using pip. I have had success using the .whl package files for these libraries to create the Lambda layer. Refer to the steps below:
NOTE: These steps set up the libraries specific to the Python 3.7 runtime. If using any other version, you would need to download the .whl files corresponding to that Python version.
Create an EC2 instance using Amazon Linux AMI and SSH into this instance. We should create our layer in Amazon Linux AMI as the Lambda Python 3.7 runtime runs on this operating system (doc).
Make sure this instance has Python3 and "pip" tool installed.
Download the numpy .whl file for the cp37 Python version and the manylinux1_x86_64 OS by executing the below command:
$ wget https://files.pythonhosted.org/packages/d6/c6/58e517e8b1fb192725cfa23c01c2e60e4e6699314ee9684a1c5f5c9b27e1/numpy-1.18.5-cp37-cp37m-manylinux1_x86_64.whl
Skip to the next step if you're not using pandas. Download the pandas .whl file for the cp37 Python version and the manylinux1_x86_64 OS by executing the below command:
$ wget https://files.pythonhosted.org/packages/a4/5f/1b6e0efab4bfb738478919d40b0e3e1a06e3d9996da45eb62a77e9a090d9/pandas-1.0.4-cp37-cp37m-manylinux1_x86_64.whl
Next, we will create a directory named "python" and unzip these files into that directory:
$ mkdir python
$ unzip pandas-1.0.4-cp37-cp37m-manylinux1_x86_64.whl -d python/
$ unzip numpy-1.18.5-cp37-cp37m-manylinux1_x86_64.whl -d python/
We also need to download "pytz" library to successfully import numpy and pandas libraries:
$ pip3 install -t python/ pytz
Next, we would remove the “*.dist-info” files from our package directory to reduce the size of the resulting layer.
$ cd python
$ sudo rm -rf *.dist-info
This will install all the required libraries that we need to run pandas and numpy.
Zip the current "python" directory and upload it to your S3 bucket. Ensure that the libraries are present in the hierarchy as given here.
$ cd ..
$ zip -r lambda-layer.zip python/
$ aws s3 cp lambda-layer.zip s3://YOURBUCKETNAME
The "lambda-layer.zip" file can then be used to create a new layer from the Lambda console.
Base on aws lamda layer doc, https://docs.aws.amazon.com/lambda/latest/dg/configuration-layers.html your zip package for the layer must have this structure.
my_layer.zip
| python/numpy
| python/numpy-***.dist-info
So what you have to do is create a folder python, and put the content of site-packages inside it, then zip up that python folder. I tried this out with a simple package and it seem to work fine.
Also keep in mind, some package require c/c++ compilation, and for that to work you must install and package on a machine with similar architecture to lambda. Usually you would need to do this on an EC2 where you install and package where it have similar architecture to the lambda.
That's bit of misleading question, because you at least did not mention you use serverless. I found it going through the snapshot of you project structure you provided. That means you probably use serverless for deployment of your project within AWS provider.
Actually, there are multiple ways you can arrange lambda layer. Let's have a look at each of them.
Native AWS
Once you will navigate to Add a layer, you will find 3 options:
[AWS Layers, Custom Layers, Specify an ARN;].
Specify an ARN Guys, who did all work for you: KLayers
so, you need numpy, okay. Within lambda function navigate to the layers --> create a new layer --> out of 3 options, choose Specify an ARN and as the value put: arn:aws:lambda:eu-west-1:770693421928:layer:Klayers-python38-numpy:12.
It will solve your problem and you will be able to work with numpy Namespace.
Custom Layers
Choose a layer from a list of layers created by your AWS account or organization.
For custom layers the way of implementing can differ based on your requirements in terms of deployment.
If are allowed to accomplish things manually, you should have a glimpse at following Medium article. I assume it will help you!
AWS Layers
As for AWS pre-build layers, all is simple.
Layers provided by AWS that are compatible with your function's runtime.
Can differentiate between runtimes
For me I have list of: Perl5, SciPy, AppConfig Extension
Serverless
Within serverless things are much easier, because you can define you layers directly with lambda definition in serverless.yml file. Afterwards, HOW to define them can differ as well.
Examples can be found at: How to publish and use AWS Lambda Layers with the Serverless Framework
If you will have any questions, feel free to expand the discussion.
Cheers!

How to fix "module 'pg8000' has no attribute 'connect'" error in AWS Glue job

I'm trying to set up a daily AWS Glue job that loads data into a RDS PostgreSQL DB. But I need to truncate my tables before loading data into them, since those jobs work on the whole dataset.
To do this, I'm implementing the solution given here: https://stackoverflow.com/a/50984173/11952393.
It uses the pure Python library pg8000. I followed the guidelines in this SO, downloading the library tar, unpacking it, adding the empty __init.py__, zipping the whole think, uploading the zip file to S3 and adding the S3 URL as a Python library in the AWS Glue job config.
When I run the job, the pg8000 module seems to be imported correctly. But then I get the following error:
AttributeError: module 'pg8000' has no attribute 'connect'
I am most certainly doing something wrong... But can't find what. Any constructive feedback is welcome!
Here is what made it work for me.
Do a pip install of the pg8000 package in a separate location
pip install -t /tmp/ pg8000
You would see 2 directories in the /tmp directory
pg8000
scramp
Zip the above 2 directories separately
cd /tmp/
zip -r pg8000.zip pg8000/
zip -r scramp.zip scramp/
Upload these 2 zip files in an S3 location
While creating the job or the Dev Endpoint mention these 2 zip files in the Python Library Path field
s3://<bucket>/<prefix>/pg8000.zip,s3://<bucket>/<prefix>/scramp.zip
Add
install_requires = ['pg8000==1.12.5']
in _setup.py file which is generating .egg file
You should able to access library.

Categories

Resources