use bundled s2i by adding package to PATH

repo2docker/app.py

@@ -144,7 +144,7 @@ class Repo2Docker(Application):
             sys.exit(1)
 
         try:
-            for line in execute_cmd(['git', 'reset', '--hard', ref], checkout_path):
+            for line in execute_cmd(['git', 'reset', '--hard', ref], cwd=checkout_path):
                 self.log.info(line, extra=dict(phase='fetching'))
         except subprocess.CalledProcessError:
             self.log.error('Failed to check out ref %s', ref, extra=dict(phase='failed'))

repo2docker/detectors.py

@@ -12,6 +12,7 @@ from pythonjsonlogger import jsonlogger
 
 from .utils import execute_cmd
 
+here = os.path.abspath(os.path.dirname(__file__))
 
 class BuildPack(LoggingConfigurable):
     name = Unicode()
@@ -73,8 +74,10 @@ class S2IBuildPack(BuildPack):
             build_image,
             output_image_spec,
         ]
+        env = os.environ.copy()
+        env['PATH'] = os.pathsep.join([here, env.get('PATH') or os.defpath])
         try:
-            for line in execute_cmd(cmd, cwd=workdir):
+            for line in execute_cmd(cmd, cwd=workdir, env=env):
                 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'))

repo2docker/utils.py

@@ -1,10 +1,10 @@
 import subprocess
 
-def execute_cmd(cmd, cwd=None):
+def execute_cmd(cmd, **kwargs):
     """
     Call given command, yielding output line by line
     """
-    proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, universal_newlines=True, cwd=cwd)
+    proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, universal_newlines=True, **kwargs)
 
     try:
         for line in iter(proc.stdout.readline, ''):