No module named 'psycopg2._psycopg': ModuleNotFoundError in AWS Lambda - aws-lambda

Question

I have created a deployment package for AWS Lambda with my python file and the dependencies including sqlalchemy and psycopg2. The code works perfectly in accessing the DB locally. But when I imported this zip file, I am getting the following error.
No module named 'psycopg2._psycopg': ModuleNotFoundError
The stack trace of the error is,
{
"errorMessage": "No module named 'psycopg2._psycopg'",
"errorType": "ModuleNotFoundError",
"stackTrace": [
[
"/var/task/DBAccessLamdaHandler.py",
50,
"lambda_handler",
"engine = create_engine(rds_host)"
],
[
"/var/task/sqlalchemy/engine/__init__.py",
387,
"create_engine",
"return strategy.create(*args, **kwargs)"
],
[
"/var/task/sqlalchemy/engine/strategies.py",
80,
"create",
"dbapi = dialect_cls.dbapi(**dbapi_args)"
],
[
"/var/task/sqlalchemy/dialects/postgresql/psycopg2.py",
554,
"dbapi",
"import psycopg2"
],
[
"/var/task/psycopg2/__init__.py",
50,
"<module>",
"from psycopg2._psycopg import ( # noqa"
]
]
}
Any help is appreciable

Answer 1

The AWS Lambda runtime environment doesn't include the PostgreSQL libraries so you need to include them within your AWS Lambda upload.
One way to do this is to get them from the jkehler/awslambda-psycopg2 repo at GitHub. Note that you don't need to build this project from scratch as the repo includes a pre-built package in the psycopg2 folder that you can simply include in your Lambda upload.

Answer 2

The psycopg2 build library from jkehler/awslambda-psycopg2 was built for python 3.6 and make sure that while uploading your code to AWS lambda, select Python Runtime environment as 3.6, and it should work. I banged my head on this for a full day and then when i changed to 3.6, the import error just vanished.
If you are going to attempt to build it yourself, remember that you must build on a machine or VM with the same architecture as your target at AWS.

Answer 3

Like other answers, psycopg2-binary worked fine for python3.9 (it looks like other package awslambda-psycopg2 was only available for python3.6).
But, if you run on MacOs before sending to aws lambda, you must specify the platform to your pip install like this:
pip3.9 install --platform=manylinux1_x86_64 --only-binary=:all: psycopg2-binary

Answer 4

Latest as of 26/MAR/2020
I was skeptical about depending on a third-party library for my production code. On research the following works,
The issue happens only when the packages are built from MAC OS.
I can confirm today that the issue is fixed when I build the package from Centos 7 ( AWS AMI )
The following is my approach
requirement.txt
psycopg2-binary==2.8.4
Build process
pip install -r requirements.txt --target .
Lambda code is in the root directory
+-- lambda_function.py
+-- psycopg2
+-- psycopg2 files
Zip the directory and test the code in lambda works.
The only additional step is to build the package in Linux env instead of macOS using the Docker container. An example can be found here: Deploy AWS Amplify Python Lambda from macOS with Docker

Answer 5

Thanks to AWS Lambda Layers we can include a ready compiled psycopg2 layer for our selected Python versions directly to our Lambda function. Please use the version you need from this Github repo. Be careful to use the correct Python version and Region in Lambda and layer creation.

Answer 6

For Windows (Looks like in any OS which is not build on Amazon AMI or Centos), the easiest fix is to use
psycopg2 Python Library for AWS Lambda
which you can find https://github.com/jkehler/awslambda-psycopg2

Answer 7

I've had issues getting SQLAlchemy to run on AWS Lambda despite the fact that I have tried multiple psycopg2 versions, but what eventually solved it for me was to use an older Python version. I went from Python 3.9 to 3.7 and it was finally able to run (Using psycopg2-binary 2.8.4, but I didn't try other versions or the none binary version with 3.7)

Answer 8

I have faced a similar issue. I tried to create the layers using AWS Cloud shell it worked with Python3.8. But failed in Python3.9 though.
Please change the region name as per your AWS Region
sudo amazon-linux-extras install python3.8
curl -O https://bootstrap.pypa.io/get-pip.py
python3.8 get-pip.py --user
mkdir python
python3.8 -m pip install --platform=manylinux1_x86_64 --only-binary=:all: pandas numpy pymysql psycopg2-binary SQLAlchemy -t python/
zip -r layer.zip python
aws lambda publish-layer-version \
--layer-name mics-layer \
--description "Pandas Numpy psycopg2-binary SQLAlchemy pymysql" \
--zip-file fileb://layer.zip \
--compatible-runtimes python3.8 python3.9 \
--region eu-west-1

Answer 9

instead of using psycopg2, try using pg8000
in command prompt go the directory that you are currently working(example F:\example)
pip install pg8000 -t. (-t. is for installing pg8000 in the directory that you are working)
// handler.py
import pg8000
database=''
host=''
port=''
user=''
password=''
conn = pg8000.connect(database=database, host=host, port=port, user=user,
password=password)
def lambda_function(event, context):
.
.
.
after writing your code zip the code and upload in your aws lambda.
It worked for me!!!

Answer 10

If you are using CDK you can use SQLAlchemy on AWS Lambda by bundling with Docker and providing the right pip install command:
Python 3.8.
sqlachemy_layer = lambda_.LayerVersion(
scope=self,
id=LAYERS_SQLALCHEMY_LAYER,
layer_version_name=LAYERS_SQLALCHEMY_LAYER,
code=lambda_.Code.from_asset(
str(pathlib.Path(__file__).parent.joinpath("dependencies").resolve()),
bundling=BundlingOptions(
image=lambda_.Runtime.PYTHON_3_8.bundling_image,
command=[
"bash", "-c",
"pip install -r requirements-sqlalchemy.txt -t /asset-output/python && cp -au . /asset-output/python",
]
)
),
compatible_runtimes=[
lambda_.Runtime.PYTHON_3_8,
],
)
Python 3.9
sqlachemy_layer = lambda_.LayerVersion(
scope=self,
id=LAYERS_SQLALCHEMY_LAYER,
layer_version_name=LAYERS_SQLALCHEMY_LAYER,
code=lambda_.Code.from_asset(
str(pathlib.Path(__file__).parent.joinpath("dependencies").resolve()),
bundling=BundlingOptions(
image=lambda_.Runtime.PYTHON_3_9.bundling_image,
command=[
"bash", "-c",
"pip3.9 install --platform=manylinux1_x86_64 --only-binary=:all: -r requirements-sqlalchemy.txt -t /asset-output/python && cp -au . /asset-output/python",
]
)
),
compatible_runtimes=[
lambda_.Runtime.PYTHON_3_9,
],
)
The requirements-sqlalchemy.txt:
psycopg2-binary
sqlalchemy
And the file structure:
dependencies/
requirements-sqlalchemy.txt
my_stack.py