add conda detector

and S2I buildpack base for common python/conda

builder/app.py

@@ -12,7 +12,7 @@ import docker
 
 import subprocess
 
-from .detectors import BuildPack, PythonBuildPack, DockerBuildPack
+from .detectors import BuildPack, PythonBuildPack, DockerBuildPack, CondaBuildPack
 from .utils import execute_cmd
 
 
@@ -53,7 +53,7 @@ class Builder(Application):
 
     buildpacks = List(
         None,
-        [DockerBuildPack, PythonBuildPack],
+        [DockerBuildPack, CondaBuildPack, PythonBuildPack],
         config=True
     )
 

builder/detectors.py

@@ -39,7 +39,6 @@ class BuildPack(LoggingConfigurable):
         pass
 
 
-
 class DockerBuildPack(BuildPack):
     name = Unicode('Dockerfile')
     def detect(self, workdir):
@@ -56,7 +55,43 @@ class DockerBuildPack(BuildPack):
                 self.log.info(progress['stream'].rstrip(), extra=dict(phase='building'))
 
 
-class PythonBuildPack(BuildPack):
+class S2IBuildPack(BuildPack):
+    def s2i_build(self, workdir, ref, output_image_spec, build_image):
+        # Note: Ideally we'd just copy from workdir here, rather than clone and check out again
+        # However, setting just --copy and not specifying a ref seems to check out master for
+        # some reason. Investigate deeper FIXME
+        cmd = [
+            's2i',
+            'build',
+            '--exclude', '""',
+            '--ref', ref,
+            workdir,
+            build_image,
+            output_image_spec,
+        ]
+        try:
+            for line in execute_cmd(cmd):
+                self.log.info(line, extra=dict(phase='building', builder=self.name))
+        except subprocess.CalledProcessError:
+            self.log.error('Failed to build image!', extra=dict(phase='failed'))
+            sys.exit(1)
+
+
+class CondaBuildPack(S2IBuildPack):
+    """Build Pack for installing from a conda environment.yml using S2I"""
+
+    name = Unicode('conda')
+    build_image = Unicode('jupyterhub/singleuser-builder-conda:v0.1.5', config=True)
+
+    def detect(self, workdir):
+        return os.path.exists(os.path.join(workdir, 'environment.yml'))
+
+    def build(self, workdir, ref, output_image_spec):
+        return self.s2i_build(workdir, ref, output_image_spec, self.build_image)
+
+
+class PythonBuildPack(S2IBuildPack):
+    """Build Pack for installing from a pip requirements.txt using S2I"""
     name = Unicode('python-pip')
     runtime_builder_map = Dict({
         'python-2.7': 'jupyterhub/singleuser-builder-venv-2.7:v0.1.5',
@@ -78,21 +113,4 @@ class PythonBuildPack(BuildPack):
             return True
 
     def build(self, workdir, ref, output_image_spec):
-        # Note: Ideally we'd just copy from workdir here, rather than clone and check out again
+        return self.s2i_build(workdir, ref, output_image_spec, self.runtime_builder_map[self.runtime])
-        # However, setting just --copy and not specifying a ref seems to check out master for
-        # some reason. Investigate deeper FIXME
-        cmd = [
-            's2i',
-            'build',
-            '--exclude', '""',
-            '--ref', ref,
-            workdir,
-            self.runtime_builder_map[self.runtime],
-            output_image_spec
-        ]
-        try:
-            for line in execute_cmd(cmd):
-                self.log.info(line, extra=dict(phase='building', builder=self.name))
-        except subprocess.CalledProcessError:
-            self.log.error('Failed to build image!', extra=dict(phase='failed'))
-            sys.exit(1)