doc: automatic builds and deployment using Forgejo Actions

Actions run in a custom Docker image built by the scripts in `doc/docker`.
There are two jobs that run in sequence:

- `build-doc`: builds the documentation from the AsciiDoc sources.
- `deploy-doc`: Uploads the generated files to http://0fm.de

.forgejo/workflows/doc.yaml

@@ -0,0 +1,24 @@
+on: [push]
+jobs:
+  build-doc:
+    runs-on: docker
+    container:
+      image: git.tkolb.de/amateurfunk/hamnet70/asciidoctor:1.6
+    steps:
+      - uses: actions/checkout@v4
+      - run: cd doc && make
+      - uses: actions/upload-artifact@v3
+        with:
+          name: documentation
+          path: doc/out/
+  deploy-doc:
+    needs: build-doc
+    runs-on: docker
+    container:
+      image: git.tkolb.de/amateurfunk/hamnet70/asciidoctor:1.6
+    steps:
+      - run: mkdir ~/.ssh && echo "${{ secrets.SSH_KEY }}" > ~/.ssh/id_ed25519 && chmod 0600 ~/.ssh/id_ed25519 && echo "${{ secrets.SSH_KNOWN_HOST }}" > ~/.ssh/known_hosts
+      - uses: actions/download-artifact@v3
+        with:
+          name: documentation
+      - run: 'rsync -e "ssh -p 2342" -r . deployment@tkolb.de:'

doc/docker/Dockerfile

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+FROM debian:stable
+
+# for basic Forgejo + AsciiDoctor support
+RUN apt update && apt install -y --no-install-recommends nodejs git ruby-rubygems make && apt clean
+
+RUN gem install asciidoctor asciidoctor-diagram
+
+# tools for diagram generation
+RUN apt install -y --no-install-recommends mscgen && apt clean
+
+# tools for automatic deployment
+RUN apt install -y --no-install-recommends rsync openssh-client && apt clean
+
+# run as unprivileged user in the container
+RUN useradd -m ciuser
+USER ciuser

doc/docker/build.sh

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+#!/bin/sh
+
+if [ -z "$1" ]; then
+	echo "usage: $0 <tag-version>"
+	exit 1
+fi
+
+docker build -t git.tkolb.de/amateurfunk/hamnet70/asciidoctor:$1 .

doc/docker/test.sh

@@ -0,0 +1,8 @@
+#!/bin/sh
+
+if [ -z "$1" ]; then
+	echo "usage: $0 <tag-version>"
+	exit 1
+fi
+
+docker run -v $(realpath ..):/doc -it git.tkolb.de/amateurfunk/hamnet70/asciidoctor:$1

doc/docker/upload.sh

@@ -0,0 +1,10 @@
+#!/bin/sh
+
+if [ -z "$1" ]; then
+	echo "usage: $0 <tag-version>"
+	exit 1
+fi
+
+docker login
+docker push git.tkolb.de/amateurfunk/hamnet70/asciidoctor:$1
+docker logout