Run build job only for master and tags

Now that the setup script handles the correct version number we can use
a single build job for stable and dev builds

.gitlab-ci.yml

 stages:
   - test
+  - build
+  - publish
 
 test:
   stage: test
@@ -12,3 +14,39 @@ test:
     - pytest
   tags:
     - docker
+
+build:
+  stage: build
+  image: python:3
+  before_script:
+    - apt-get update
+    - apt-get install libgirepository1.0-dev -y
+    - pip install .[build]
+  script:
+    - python3 setup.py sdist bdist_wheel
+  tags:
+    - docker
+  artifacts:
+    paths:
+      - dist/*
+    expire_in: 1 week
+  only:
+    - tags@funkwhale/mopidy
+    - master@funkwhale/mopidy
+
+publish:
+  stage: publish
+  image: python:3
+  before_script:
+    - apt-get update
+    - apt-get install libgirepository1.0-dev -y
+    - pip install .[publish]
+  script:
+    - twine upload dist/*
+  tags:
+    - docker
+  dependencies:
+    - build
+  only:
+    - tags@funkwhale/mopidy
+    - master@funkwhale/mopidy

setup.cfg

 [metadata]
 name = mopidy_funkwhale
 description = "A backend extension for mopidy to stream music from a Funkwhale server"
-version = 0.1.0
-author = Eliot Berriot
+author = The Funkwhale Collective
 author_email = contact+funkwhale@eliotberriot.com
 url = https://dev.funkwhale.audio/funkwhale/mopidy
 long_description = file: README.rst
@@ -40,6 +39,13 @@ dev =
     ipython
     ipdb
 
+build =
+    setuptools
+    wheel
+
+publish =
+    twine
+
 [options.packages.find]
 exclude =
     tests

setup.py

 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
+import codecs
+import os
 from setuptools import setup
 
-setup()
+def read(rel_path):
+    here = os.path.abspath(os.path.dirname(__file__))
+    with codecs.open(os.path.join(here, rel_path), 'r') as fp:
+        return fp.read()
+
+def get_version():
+    tag = os.getenv('CI_COMMIT_TAG', None)
+    if tag:
+        return tag
+
+    for line in read("mopidy_funkwhale/__init__.py").splitlines():
+        if line.startswith('__version__'):
+            delim = '"' if '"' in line else "'"
+            version = line.split(delim)[1]
+            iid = os.getenv('CI_PIPELINE_IID', 0)
+            return "{}.dev{}".format(version, iid)
+    raise RuntimeError("Unable to find version string.")
+
+setup(
+    version=get_version(),
+)