opencv layer does not work

Question

Hi Team,
I created an opencv layer for my python3.9 app in lambda as below, but no one works
* arn:aws:lambda:ap-southeast-1:777606541103:layer:opencv_layer:5
* arn:aws:lambda:ap-southeast-1:777606541103:layer:opencv_layer:4
* arn:aws:lambda:ap-southeast-1:777606541103:layer:opencv_layer:3
* arn:aws:lambda:ap-southeast-1:777606541103:layer:opencv_layer:2

our lambda is built with Ubuntu, and I tried building the layer with both Ubuntu and Amazonlinux, But no one works. 
I got the Error on the deployment and I attached the screenshot of the error
> ModuleNotFoundError: No module named 'cv2'
!(/media/postImages/original/IMWhXjpO-NR7y_yEyOdY6Zdg)

**1. Docker file content**
**Ubuntu Docker File**
*FROM ubuntu
RUN apt-get update && \
    apt-get install -y python3.9 python3-pip &&  \
    pip3 install opencv-python-headless`*

**AmazonLinux Docker File**
*FROM amazonlinux

RUN yum install -y python3.9
RUN yum install -y python3-pip
RUN pip3 install opencv-python-headless*

2. Extract OpenCV Artifacts:
docker create --name opencv-extractor opencv-builder
docker cp opencv-extractor:/usr/local/lib64/python3.9/site-packages/ ./opencv_layer/

3. Create a Lambda Layer Package
*cd opencv_layer
zip -r opencv_layer.zip .*

4. Upload and create the layer listed at start of the questions

5. The below is part of my Chalice config.json file for deployment
  "stages": {
    "dev": {
      "layers": [
        "arn:aws:lambda:ap-southeast-1:777606541103:layer:opencv_layer:5"
      ],
      "autogen_policy": true,

I swithed the os between amazonlinux and ubuntu and swithed the folder of the zip file, but I have not found the correct way on it. Please help to check.

Thank you

Answer

The problem is how you’re installing and zipping the python libraries.

Every thing needs to be in a python folder as follows.

First, create a directory to hold everything. Replace my_layername with the name of your layer package

```
mkdir -p my-layername/python
```

Now install everything into the python directory

```
cd lambdalayer
cd python
pip3 install opencv-python-headless --target=.
```

Optional, but recommended -- remove unneeded files to reduce the size of your layer package. Note the last exit is only if you are running this inside a container:

```
rm -rf *.dist-info
find . -name "tests" -type d | xargs -I{} rm -rf {}
find . -name "docs" -type d | xargs -I{} rm -rf {}
find . -name "__pycache__" -type d | xargs -I{} rm -rf {}
rm -rf boto*
```

Now zip up the layer

```
cd my-layername
zip -r my-layername.zip python
```

Upload your layer to lambda.

Answer

Hello,

In order to import "opencv" module in your Lambda function as a layer you can refer to the below mentioned GitHub repository[+], it has the detailed steps mentioned on how to import cv2 in your Lambda function.

[+] https://github.com/awslabs/lambda-opencv

Additionally, you can create container based Lambda function and bake your on customer modules in the Dockerfile as it give you the ability to add modules/dependencies beyond 250MB.

[+] https://docs.aws.amazon.com/lambda/latest/dg/python-image.html

Thank you

opencv layer does not work

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