[IMP] t2d: add new argument --build-extra-steps

Similar to --run-extra-cmds, --build-extra-cmds, this new argument
allows users to add extra steps at the end of the generated Dockerfile.

Closes #209.

src/travis2docker/cli.py

@@ -184,6 +184,13 @@ def main(return_result=False):
         default=False,
         help='Use the image generated from the CI and used in deployV',
     )
+    parser.add_argument(
+        '--build-extra-steps',
+        nargs='*',
+        default="",
+        dest='build_extra_steps',
+        help='Append these extra steps at the end of the Dockerfile',
+    )
 
     args = parser.parse_args()
     revision = args.git_revision
@@ -250,6 +257,7 @@ def main(return_result=False):
         runs_at_the_end_script=runs_at_the_end_script,
         build_env_args=build_env_args,
         deployv=deployv,
+        build_extra_steps=args.build_extra_steps,
     )
     t2d.build_extra_params = {
         'extra_params': build_extra_args,

src/travis2docker/templates/Dockerfile

@@ -39,6 +39,10 @@ RUN apt-get update; apt-get install {{ ' '.join(packages) }}
 
 RUN echo "TRAVIS_PYTHON_VERSION={{ python_version }}" >> /etc/environment
 
+{% for step in build_extra_steps %}
+RUN {{ step }}
+{% endfor %}
+
 USER {{ user }}
 ENV TRAVIS_PYTHON_VERSION={{ python_version }}
 ENV TRAVIS_REPO_SLUG={{ repo_owner }}/{{ repo_project }}

src/travis2docker/templates/Dockerfile_deployv

@@ -39,6 +39,9 @@ RUN . /home/odoo/build.sh && \
     mv /entry_point.py /deployv_entry_point.py && \
     mkdir /run/sshd
 
+{% for step in build_extra_steps %}
+RUN {{ step }}
+{% endfor %}
 
 USER {{ user }}
 

src/travis2docker/travis2docker.py

@@ -77,6 +77,7 @@ def __init__(
         runs_at_the_end_script=None,
         build_env_args=None,
         deployv=None,
+        build_extra_steps=None,
     ):
         self._python_versions = []
         self.curr_work_path = None
@@ -87,6 +88,7 @@ def __init__(
         self.deployv = deployv
         self.runs_at_the_end_script = ["sleep 2"] if runs_at_the_end_script is None else runs_at_the_end_script
         self.variables_sh_data = {}
+        self.build_extra_steps = build_extra_steps
         if deployv:
             self.variables_sh_data = {
                 var.lower(): value for _, _, var, value in self.re_export.findall(os_kwargs['variables_sh'])
@@ -316,6 +318,7 @@ def compute_dockerfile(self, skip_after_success=False):
                         'sources': [],
                         'rvm_env_path': rvm_env_relpath,
                         'build_env_args': self.build_env_args,
+                        'build_extra_steps': self.build_extra_steps,
                     }
                     with open(curr_dockerfile, "w") as f_dockerfile, open(entryp_path, "w") as f_entrypoint, open(
                         rvm_env_path, "w"