added Java image for Gitea runner

.gitea/workflows/build-gitea-runner.yaml

@@ -17,11 +17,12 @@ jobs:
           username: woggioni
           password: ${{ secrets.PUBLISHER_TOKEN }}
       -
-        name: Build and push Gitea runner images
+        name: Build and push runner image
         uses: docker/build-push-action@v6
         with:
           builder: multiplatform-builder
           context: "{{defaultContext}}:gitea-runner"
+          target: runner
           platforms: |
             linux/amd64
             linux/arm64
@@ -30,3 +31,18 @@ jobs:
           tags: |
             "gitea.woggioni.net/woggioni/gitea-runner:latest"
 
+      -
+        name: Build and push java image
+        uses: docker/build-push-action@v6
+        with:
+          builder: multiplatform-builder
+          context: "{{defaultContext}}:gitea-runner"
+          target: java
+          platforms: |
+            linux/amd64
+            linux/arm64
+          push: true
+          pull: true
+          tags: |
+            "gitea.woggioni.net/woggioni/gitea-runner/java:latest"
+

gitea-runner/Dockerfile

@@ -1,7 +1,19 @@
-FROM alpine:3.24
+FROM alpine:3.24 AS runner
 RUN echo "@testing https://dl-cdn.alpinelinux.org/alpine/edge/testing" >> /etc/apk/repositories
 RUN --mount=type=cache,target=/var/cache/apk apk update
-RUN --mount=type=cache,target=/var/cache/apk apk add gitea-runner@testing nodejs docker
+RUN --mount=type=cache,target=/var/cache/apk apk add gitea-runner@testing nodejs docker shadow
+RUN usermod -u 555 gitea-runner
+RUN groupmod -g 103 docker
+RUN addgroup gitea-runner docker
 USER gitea-runner
 WORKDIR /var/lib/gitea-runner
 CMD ["/usr/bin/gitea-runner", "daemon", "--config", "/etc/gitea-runner/config.yaml"]
+
+FROM debian:stable-slim AS java
+RUN --mount=type=cache,target=/var/cache/apt,sharing=locked \
+    --mount=type=cache,target=/var/lib/apt,sharing=locked \
+    apt update &&\
+    apt install -y nodejs
+RUN useradd gitea-runner -d /var/lib/gitea-runner -u 555 -r
+USER gitea-runner
+WORKDIR /var/lib/gitea-runner