How to build a layer from a Dockerfile

Step 1: Prepare a Dockerfile

Create a Dockerfile with the following content:

# Use the build-latest image for the same runtime version as your function.
# If you are in the Chinese mainland, pull from registry.cn-beijing.aliyuncs.com instead.
FROM aliyunfc/runtime-nodejs14:build-latest

# Set environment variables and working directory.
ENV PATH /opt/bin:$PATH
ENV LD_LIBRARY_PATH /opt/lib
ENV NODE_PATH /opt/nodejs/node_modules
WORKDIR /tmp

# Install Puppeteer to /opt/nodejs.
COPY ./package.json /opt/nodejs/
RUN cd /opt/nodejs \
    && npm --registry https://registry.npmmirror.com i

# Download system dependency .deb files to /tmp/install/archives.
RUN mkdir -p /opt/lib /tmp/install
RUN apt-get update && apt-get install -y -d -o=dir::cache=/tmp/install \
    libblas3 fonts-liberation libappindicator3-1 libasound2 libatk-bridge2.0-0 \
    libgtk-3-0 libnspr4 libnss3 libpangocairo-1.0-0 libxcb-dri3-0 \
    libx11-xcb1 libxcb1 libxss1 libxtst6 lsb-release \
    xdg-utils libatspi2.0-0 libatk1.0-0 libxkbcommon0 libepoxy0 \
    libglapi-mesa libnspr4 libgbm-dev \
    --reinstall --no-install-recommends

# Extract .so files from each .deb package.
RUN for f in $(ls /tmp/install/archives/*.deb); do \
        echo "Preparing to unpack ${f##*/}"; \
        cd /tmp/install/archives; \
        dpkg-deb -x ${f##*/} /tmp/install; \
    done;

# Copy extracted .so files to /opt/lib.
RUN cp -r /tmp/install/usr/bin /opt/; \
    cp -r /tmp/install/usr/lib/x86_64-linux-gnu/* /opt/lib/

# Package /opt into layer.zip.
# The -y flag preserves symbolic links. .[^.]* includes hidden files without the parent directory.
RUN cd /opt \
    && zip -ry layer.zip * .[^.]*

CMD ["bash"]

The base image runtime version must match the runtime version of your function. Use the build-latest tag for layer builds.

Step 2: Build the layer ZIP file

1. Build the Docker image from the Dockerfile:

   sudo docker build -t <layer-image-name> -f Dockerfile .

2. Copy the layer ZIP file out of the image:

   sudo docker run --rm -v $(pwd):/tmp <layer-image-name> sh -c "cp /opt/layer.zip /tmp/"

   This command mounts your current directory as /tmp inside the container, then copies layer.zip to it. After the command completes, layer.zip appears in your current directory. The --rm flag removes the container automatically.

Step 3: Create a custom layer

In the Function Compute console or using Serverless Devs, create a layer and set Layer Upload Method to Upload Layer in ZIP Package. For detailed steps, see Create a custom layer.