How to add github secrets to env variable

Below is the yml file, I hope to add github secrets to env variable.

name: Publish Docker image
on:
  push:
    branches: [ main ]

jobs:
  push_to_registry:
    name: Push Docker image to Docker Hub
    runs-on: ubuntu-latest

    steps:
      - name: Check out the repo
        uses: actions/checkout@v2

      - name: Log in to Docker Hub
        uses: docker/login-action@v1
        with:
          username: ${{ secrets.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}

      - name: Push to Docker Hub
        uses: docker/build-push-action@v2
        with:
          push: true
          tags: docker_hub_name/image_name:latest
          secrets: |
            "MYSQL_HOST=${{ secrets.MYSQL_HOST}}"
            "MYSQL_USER=${{ secrets.MYSQL_USER}}"
            "MYSQL_PASSWORD=${{ secrets.MYSQL_PASSWORD}}"
            "MYSQL_PORT=${{ secrets.MYSQL_PORT }}"

Then use syntax os.environ.get("MYSQL_HOST", "") to get my database information when build image.

But use the below method still not work, have something syntax wrong? or other methods can do it?

secrets: |
  "MYSQL_HOST=${{ secrets.MYSQL_HOST}}"
  "MYSQL_USER=${{ secrets.MYSQL_USER}}"
  "MYSQL_PASSWORD=${{ secrets.MYSQL_PASSWORD}}"
  "MYSQL_PORT=${{ secrets.MYSQL_PORT }}"

[AndreiCalazans]

This worked for me. Thanks, I documented everything here https://andrei-calazans.com/posts/2021-06-23/passing-secrets-github-actions-docker

[crazy-max]

@machineCYC

Create the secrets locally. before executing the blue color comment?

Yes

How to create the secrets locally?

https://docs.docker.com/engine/reference/commandline/secret_create/#create-a-secret

You can also provide secrets through env vars. So let’s say you already have the env var MYSQL_HOST set locally, you can then set secret in buildx command: --secret id=mysql_host,env=MYSQL_HOST and use it like this in your Dockerfile:

RUN --mount=type=secret,id=mysql_host \
  export MYSQL_HOST=$(cat /run/secrets/mysql_host) && \
  echo $MYSQL_HOST