Create pypi_twine_executable

Like we do for bindep and tox roles. Allow a user to manage the twine
binary outside of the upload-pypi role. This allows a user to better
control the path of the executable too.

Change-Id: I5c757b29e185ab76495abf3cfb2d853aada77a50
Signed-off-by: Paul Belanger <pabelanger@redhat.com>

roles/upload-pypi/README.rst

@@ -30,3 +30,8 @@ Upload python packages to PyPI
    :default: src/{{ zuul.project.canonical_name }}/dist
 
    Path containing artifacts to upload.
+
+.. zuul:rolevar:: pypi_twine_executable
+   :default: twine
+
+   Path to twine executable.

roles/upload-pypi/defaults/main.yaml

@@ -2,3 +2,4 @@
 pypi_path: "src/{{ zuul.project.canonical_name }}/dist"
 pypi_repository: "{{ pypi_info.repository|default('pypi') }}"
 pypi_repository_url: "{{ pypi_info.repository_url|default('https://pypi.python.org/pypi') }}"
+pypi_twine_executable: twine

roles/upload-pypi/tasks/main.yaml

@@ -1,12 +1,3 @@
-- name: Check for twine install
-  command: which twine
-  ignore_errors: yes
-  register: twine_command_which
-
-- name: Ensure twine is installed
-  command: pip install --user twine
-  when: not twine_command_which|succeeded
-
 - name: Install .pypirc configuration file
   template:
     dest: ~/.pypirc
@@ -20,7 +11,7 @@
   register: found_wheels
 
 - name: Upload wheel with twine before tarballs
-  command: "twine upload -r {{ pypi_repository }} {{ item.path }}"
+  command: "{{ pypi_twine_executable }} upload -r {{ pypi_repository }} {{ item.path }}"
   with_items: "{{ found_wheels.files }}"
   when: found_wheels.matched|bool
 
@@ -31,6 +22,6 @@
   register: found_tarballs
 
 - name: Upload tarballs with twine
-  command: "twine upload -r {{ pypi_repository }} {{ item.path }}"
+  command: "{{ pypi_twine_executable }} upload -r {{ pypi_repository }} {{ item.path }}"
   with_items: "{{ found_tarballs.files }}"
   when: found_tarballs.matched|bool