Simplified the build_docker_image function (#1887)

* Simplified the build_docker_image function

* Extracted 'Dockerfile' into a variable
Addressed PR feedback

* Fixed conflict with updated master.

* Addressed the feedback

sdk/python/kfp/compiler/_component_builder.py

@@ -282,23 +282,6 @@ def __init__(self, gcs_staging, target_image, namespace):
     self._arc_requirement_filename = 'requirements.txt'
     self._container_builder = ContainerBuilder(gcs_staging, gcr_image_tag=target_image, namespace=namespace)
 
-  def _prepare_files(self, local_dir, docker_filename, python_filename=None, requirement_filename=None):
-    """ _prepare_buildfiles generates the tarball with all the build files
-    Args:
-      local_dir (dir): a directory that stores all the build files
-      docker_filename (str): docker filename
-      python_filename (str): python filename
-      requirement_filename (str): requirement filename
-    """
-    dst_docker_filepath = os.path.join(local_dir, self._arc_docker_filename)
-    shutil.copyfile(docker_filename, dst_docker_filepath)
-    if python_filename is not None:
-      dst_python_filepath = os.path.join(local_dir, self._arc_python_filename)
-      shutil.copyfile(python_filename, dst_python_filepath)
-    if requirement_filename is not None:
-      dst_requirement_filepath = os.path.join(local_dir, self._arc_requirement_filename)
-      shutil.copyfile(requirement_filename, dst_requirement_filepath)
-
   def build_image_from_func(self, component_func, base_image, timeout, dependency, python_version='python3'):
     """ build_image builds an image for the given python function
     args:
@@ -325,12 +308,6 @@ def build_image_from_func(self, component_func, base_image, timeout, dependency,
       logging.info('Generate build files.')
       return self._container_builder.build(local_build_dir, self._arc_docker_filename, timeout=timeout)
 
-  def build_image_from_dockerfile(self, docker_filename, timeout):
-    """ build_image_from_dockerfile builds an image based on the dockerfile """
-    with tempfile.TemporaryDirectory() as local_build_dir:
-      self._prepare_files(local_build_dir, docker_filename)
-      return self._container_builder.build(local_build_dir, self._arc_docker_filename, timeout=timeout)
-
 def _configure_logger(logger):
   """ _configure_logger configures the logger such that the info level logs
   go to the stdout and the error(or above) level logs go to the stderr.
@@ -455,7 +432,14 @@ def build_docker_image(staging_gcs_path, target_image, dockerfile_path, timeout=
     namespace (str): the namespace within which to run the kubernetes kaniko job, default is "kubeflow"
   """
   _configure_logger(logging.getLogger())
-  builder = ComponentBuilder(gcs_staging=staging_gcs_path, target_image=target_image, namespace=namespace)
-  image_name_with_digest = builder.build_image_from_dockerfile(docker_filename=dockerfile_path, timeout=timeout)
+
+  with tempfile.TemporaryDirectory() as local_build_dir:
+    dockerfile_rel_path = 'Dockerfile'
+    dst_dockerfile_path = os.path.join(local_build_dir, dockerfile_rel_path)
+    shutil.copyfile(dockerfile_path, dst_dockerfile_path)
+
+    container_builder = ContainerBuilder(staging_gcs_path, target_image, namespace=namespace)
+    image_name_with_digest = container_builder.build(local_build_dir, dockerfile_rel_path, timeout)
+
   logging.info('Build image complete.')
   return image_name_with_digest