wip: experiment with drone cache

Try to make builds faster

.drone.yml

@@ -5,7 +5,6 @@ name: test
 
 trigger:
   event:
-    - push
     - pull_request
 
 steps:
@@ -17,6 +16,23 @@ steps:
       PGHOST: db
     commands:
       - while ! pg_isready; do sleep 1; done
+
+  - name: restore cache
+    image: 'meltwater/drone-cache:dev'
+    pull: true
+    settings:
+      archive_format: gzip
+      backend: filesystem
+      cache_key: volume
+      mount:
+        - _build
+        - deps
+      restore: true
+      exit_code: true
+    volumes:
+      - name: cache
+        path: /tmp/cache
+
   - name: test
     image: 'elixir:1.13.4'
     environment:
@@ -28,9 +44,29 @@ steps:
       - mix do local.rebar --force, local.hex --force, deps.get, deps.compile
       - mix test --cover --trace --slowest 10
 
+  - name: rebuild cache
+    image: 'meltwater/drone-cache:dev'
+    pull: true
+    settings:
+      archive_format: gzip
+      backend: filesystem
+      cache_key: volume
+      mount:
+        - _build
+        - deps
+      rebuild: true
+      exit_code: true
+    volumes:
+      - name: cache
+        path: /tmp/cache
+
 services:
   - name: db
     image: 'postgres:14.2-alpine'
     environment:
       POSTGRES_USER: postgres
       POSTGRES_PASSWORD: postgres
+
+volumes:
+  - name: cache
+    temp: {}