add a woodpecker pipeline for publishing docker images

.woodpecker/debug.yaml

@@ -17,9 +17,9 @@ steps:
   - name: build
     image: nixpkgs/nix:nixos-22.05
     commands:
-      - nix build --extra-experimental-features nix-command --extra-experimental-features flakes .#packages.x86_64-linux.debug
+      - nix build -j4 --extra-experimental-features nix-command --extra-experimental-features flakes .#packages.x86_64-linux.debug
 
   - name: test
     image: nixpkgs/nix:nixos-22.05
     commands:
-      - nix build --extra-experimental-features nix-command --extra-experimental-features flakes .#packages.x86_64-linux.test
+      - nix build -j4 --extra-experimental-features nix-command --extra-experimental-features flakes .#packages.x86_64-linux.test

.woodpecker/publish.yaml

@@ -0,0 +1,18 @@
+when:
+  event:
+  - deployment
+  - cron
+
+steps:
+  - name: docker build and publish
+    image: nixpkgs/nix:nixos-22.05
+    environment:
+      DOCKER_AUTH:
+        from_secret: docker_auth
+      commands:
+        - mkdir -p /root/.docker
+        - echo $DOCKER_AUTH > /root/.docker/config.json
+        - export CONTAINER_TAG=${CI_COMMIT_TAG:-$CI_COMMIT_SHA}
+        - nix-build -j4 --extra-experimental-features nix-command --extra-experimental-features flakes .#packages.x86_64-linux.docker
+        - nix-shell -p gzip --run "gunzip -c ./result > image.tar"
+        - nix-shell -p crane --run "crane push ./image.tar dxflrs/tricot:$CONTAINER_TAG"