[`firestartr-workflows`] Add alternate mode to build docker images

What and why

Use case

As a platform engineer I want to improve de DX of the devteam, by creating an alternate way to build the project image, without the need of a Dockerfile, and also improve the control over the base images that the development teams can use inside their organization.

To achieve that we would need some refactor in config file to add new optional block for flavor:

fs_builder:
  technology: spa-node:18-rev23
  template: spa-rev3
  template_args: 
     REWRITE_RULES : {}
  extra_packages: ["git"]  # Extra system packages to install
  build_commands: [npm ci && npm run build] # commands to build the artifact to install in the image
  build_args: ["VITE_API_URL=https://my-url"]  # Arguments to pass to the build system

How

Base images

The technology would define a pair of docker images, which the platform team will create and maintain: one for run and one for build (and for CI workflows, see https://github.com/prefapp/firestarter-workflows/blob/main/firestarter/tests/fixtures/workflow.yaml)

In the previous example:

spa:rev23-run
spa-node:18-rev23-build

Also, this images, although can be based on the public ones, must be published in the org registry.

Template (type of component)

For the construction of the artifact, we need to know the type of artifact to build, and based on this, use a serie of related steps to get the image, according to the organization and the definitions made by the platform team.

For example to build a spa image we will use something like the following template:

FROM spa-node:18-rev23-build AS builder

ARG VITE_API_URL="https://my-dev-url"

WORKDIR /app

COPY code code

RUN npm ci && npm build 

FROM spa-node:18-rev23-run # nginx-stable

RUN apt-get update && apt-get install git -y

COPY --from=builder /app/dist /app

COPY docker/default.conf /etc/nginx/conf.d/

RUN chown -R nginx:nginx /client && chmod -R 755 /app && \
    chown -R nginx:nginx /var/cache/nginx && \
    chown -R nginx:nginx /var/log/nginx && \
    chown -R nginx:nginx /etc/nginx/conf.d

RUN touch /var/run/nginx.pid && \
    chown -R nginx:nginx /var/run/nginx.pid

USER nginx

EXPOSE 8080

CMD ["nginx", "-g", "daemon off;"]

prefapp / firestarter-workflows