repo2docker/repo2docker/buildpacks/docker.py

"""Generates a variety of Dockerfiles based on an input matrix
"""
import os
import docker
from .base import BuildPack


class DockerBuildPack(BuildPack):
    """Docker BuildPack"""
    dockerfile = "Dockerfile"

    def detect(self):
        """Check if current repo should be built with the Docker BuildPack"""
        return os.path.exists(self.binder_path('Dockerfile'))

    def render(self):
        """Render the Dockerfile using by reading it from the source repo"""
        Dockerfile = self.binder_path('Dockerfile')
        with open(Dockerfile) as f:
            return f.read()

    def build(self, client, image_spec, memory_limit, build_args, cache_from, extra_build_kwargs):
        """Build a Docker image based on the Dockerfile in the source repo."""
        limits = {
            # Always disable memory swap for building, since mostly
            # nothing good can come of that.
            'memswap': -1
        }
        if memory_limit:
            limits['memory'] = memory_limit

        build_kwargs = dict(
            path=os.getcwd(),
            dockerfile=self.binder_path(self.dockerfile),
            tag=image_spec,
            buildargs=build_args,
            decode=True,
            forcerm=True,
            rm=True,
            container_limits=limits,
            cache_from=cache_from
        )

        build_kwargs.update(extra_build_kwargs)

        for line in client.build(**build_kwargs):
            yield line