Related to issue #83: Added support for container image

.github/workflows/docker.yml

@@ -0,0 +1,44 @@
+name: Create and publish Docker image
+
+on:
+  push:
+    branches: ['main']
+
+env:
+  REGISTRY: ghcr.io
+  IMAGE_NAME: ${{ github.repository }}
+
+jobs:
+  build-and-push-image:
+    runs-on: ubuntu-latest
+    # Sets the permissions granted to the `GITHUB_TOKEN` for the actions in this job.
+    permissions:
+      contents: read
+      packages: write
+      # 
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+      # Uses the `docker/login-action` action to log in to the Container registry registry using the account and password that will publish the packages. Once published, the packages are scoped to the account defined here.
+      - name: Log in to the Container registry
+        uses: docker/login-action
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      # This step uses [docker/metadata-action](https://github.com/docker/metadata-action#about) to extract tags and labels that will be applied to the specified image. The `id` "meta" allows the output of this step to be referenced in a subsequent step. The `images` value provides the base name for the tags and labels.
+      - name: Extract metadata (tags, labels) for Docker
+        id: meta
+        uses: docker/metadata-action
+        with:
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+      # This step uses the `docker/build-push-action` action to build the image, based on your repository's `Dockerfile`. If the build succeeds, it pushes the image to GitHub Packages.
+      # It uses the `context` parameter to define the build's context as the set of files located in the specified path. For more information, see "[Usage](https://github.com/docker/build-push-action#usage)" in the README of the `docker/build-push-action` repository.
+      # It uses the `tags` and `labels` parameters to tag and label the image with the output from the "meta" step.
+      - name: Build and push Docker image
+        uses: docker/build-push-action
+        with:
+          context: .
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}

.gitignore

@@ -0,0 +1 @@
+.history

Dockerfile

@@ -0,0 +1,28 @@
+## Go builder image
+FROM golang:1.22 as builder
+
+ENV GOPATH=/usr/local/go/bin
+
+WORKDIR /go
+
+COPY . .
+
+RUN CGO_ENABLED=0 go build -ldflags "-s" -a -installsuffix cgo .
+
+## Base image for production usage
+FROM alpine:3.14 as production
+
+COPY --from=builder /go/kubectl-slice /usr/bin/kubectl-slice
+
+WORKDIR /workdir
+
+## add user k8s to run the slice tool
+RUN set -eux; \
+  addgroup -g 1000 k8s; \
+  adduser -u 1000 -G k8s -s /bin/sh -h /home/k8s -D k8s
+
+RUN chown -R k8s:k8s /workdir
+
+USER k8s
+
+CMD ["/bin/sh", "-c"]

docs/docker.md

@@ -0,0 +1,43 @@
+# Running in docker  
+
+Run the Docker image from `gchr.io/patrickdappollonio/kubectl-slice`
+
+## Usage
+The container is build to execute both interactive and inline.  
+
+### Interactive shell
+
+Example, this will start the container in the `/workdir` directory.
+```sh
+docker run --rm -it \
+gchr.io/patrickdappollonio/kubectl-slice /bin/sh
+```
+
+### Inline
+
+**Example 1:**  
+This will split the `ingress-namespace.yaml` file in the directory `${PWD}/slice/testdata`.  
+
+```sh
+docker run --rm -v \
+"${PWD}/slice/testdata":/workdir gchr.io/patrickdappollonio/kubectl-slice \
+kubectl-slice -f ingress-namespace.yaml -o ./
+```
+
+**Example 2:**  
+To display the `kubectl-slice` help.  
+
+```sh
+docker run --rm -v \
+"${PWD}/slice/testdata":/workdir gchr.io/patrickdappollonio/kubectl-slice \
+kubectl-slice -h
+```
+
+**Example 3:**  
+Statements to `kubectl-slice` can be wrapped in `""` if the commandline escapes unintentionally.   
+
+```sh
+docker run --rm -v \
+"${PWD}/slice/testdata":/workdir gchr.io/patrickdappollonio/kubectl-slice \
+kubectl-slice "-h"
+```