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

user_6410520 0
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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

aws-lambda amazon-rds psycopg2
9 Answers
user_74475420

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

user_39554380

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
user_14880550
user_76340990

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)

user_170138000

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!!!

user_139738800

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.

user_16441720

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
user_28683670
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