add legacy binder dockerfile buildpack

- stages files, which previous binder did automatically and repo2docker does not
- installs required versions of ipykernel, jupyterhub, notebook
- registers kernelspecs explicitly
- launches notebook server with python3 env
- removes nb_conda_kernels, which was causing trouble
- sets JUPYTER_PATH so kernelspecs and extensions that were being installed into the python 2 env will still be picked up

repo2docker/app.py

@@ -24,7 +24,10 @@ from docker.utils import kwargs_from_env
 
 import subprocess
 
-from .detectors import BuildPack, PythonBuildPack, DockerBuildPack, CondaBuildPack
+from .detectors import (
+    BuildPack, PythonBuildPack, DockerBuildPack, LegacyBinderDockerBuildPack,
+    CondaBuildPack,
+)
 from .utils import execute_cmd
 from . import __version__
 
@@ -90,7 +93,7 @@ class Repo2Docker(Application):
 
     buildpacks = List(
         Type(BuildPack),
-        [DockerBuildPack, CondaBuildPack, PythonBuildPack],
+        [LegacyBinderDockerBuildPack, DockerBuildPack, CondaBuildPack, PythonBuildPack],
         config=True,
         help="""
         Ordered list of BuildPacks to try to use to build a git repository.

repo2docker/detectors.py

@@ -50,7 +50,44 @@ class DockerBuildPack(BuildPack):
                 else:
                     sys.stdout.write(progress['stream'])
 
-_legacybinder_docker_appendix = """
+_legacy_binder_docker_appendix = """
+USER root
+COPY . /home/main/notebooks
+RUN chown -R main:main /home/main/notebooks
+USER main
+WORKDIR /home/main/notebooks
+ENV PATH /home/main/anaconda2/envs/python3/bin:$PATH
+RUN conda install -n python3 notebook==5.0.0 ipykernel==4.6.0 && \
+    pip install jupyterhub==0.7.2 && \
+    conda remove -n python3 nb_conda_kernels && \
+    conda install -n root ipykernel==4.6.0 && \
+    /home/main/anaconda2/envs/python3/bin/ipython kernel install --sys-prefix && \
+    /home/main/anaconda2/bin/ipython kernel install --prefix=/home/main/anaconda2/envs/python3
+ENV JUPYTER_PATH /home/main/anaconda2/share/jupyter:$JUPYTER_PATH
+CMD jupyter notebook --ip 0.0.0.0
+"""
+
+class LegacyBinderDockerBuildPack(DockerBuildPack):
+    
+    name = Unicode('Legacy Binder Dockerfile')
+    def detect(self, workdir):
+        dockerfile = os.path.join(workdir, 'Dockerfile')
+        if not os.path.exists(dockerfile):
+            return False
+        with open(dockerfile, 'r') as f:
+            for line in f:
+                if line.startswith('FROM'):
+                    if 'andrewosh/binder-base' in line.split('#')[0].lower():
+                        self.amend_dockerfile(dockerfile)
+                        return True
+                    else:
+                        return False
+        # No FROM?!
+        return False
+
+    def amend_dockerfile(self, dockerfile):
+        with open(dockerfile, 'a') as f:
+            f.write(_legacy_binder_docker_appendix)
 
 
 class S2IBuildPack(BuildPack):