Update version variable during build

.drone.yml

@@ -9,7 +9,7 @@ services:
     COUCHDB_PASSWORD: password
 
 steps:
-- name: test
+- name: Run Tests
   image: python:3.6
   environment:
     COUCH_URL: 'http://couchdb:5984'
@@ -35,7 +35,24 @@ kind: pipeline
 name: publish
 
 steps:
-- name: docker-dev
+- name: Update version (development)
+  image: python:3.6
+  commands:
+  - sed -i "s/.dev/.dev${DRONE_BUILD_NUMBER}/" src/humulus/_version.py
+  when:
+    event:
+      exclude:
+      - tag
+
+- name: Update version (release)
+  image: python:3.6
+  commands:
+  - sed -i "s/.dev//" src/humulus/_version.py
+  when:
+    event:
+    - tag
+
+- name: Publish development docker image
   image: plugins/docker
   settings:
     username:
@@ -44,13 +61,13 @@ steps:
       from_secret: DOCKER_PASSWORD
     repo: shouptech/humulus
     tags:
-    - ${DRONE_COMMIT_SHA}
+    - ${DRONE_BUILD_NUMBER}
   when:
     event:
       exclude:
       - pull_request
 
-- name: docker-latest
+- name: Publish latest docker image
   image: plugins/docker
   settings:
     username:
@@ -67,7 +84,7 @@ steps:
       exclude:
       - pull_request
 
-- name: docker-release
+- name: Publish release docker image
   image: plugins/docker
   settings:
     username:

src/humulus/_version.py

@@ -12,4 +12,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-__version__ = "0.0.1"
+# The 'dev' portion of this variable will get updated during Drone CI builds
+# with a build number for all non-tagged builds.
+__version__ = "0.0.1.dev"