ci: create github release on tag (#212)

Adds a GitHub workflow to create a GitHub release (with uploaded artifacts) when a tag is pushed.

.github/workflows/release.yaml

@@ -0,0 +1,46 @@
+name: Create release
+
+on:
+  push:
+    tags:
+      - "v*"
+
+env:
+  GH_TAG: ${{github.ref_name}}
+
+permissions:
+  contents: write
+
+jobs:
+  build-release-binaries:
+    name: Build Relase Binaries
+    runs-on: ubuntu-latest
+    steps:
+      # https://github.com/actions/checkout
+      - uses: actions/checkout@v4
+      # Build the binaries using the `build/artifacts.sh` script in the repo
+      - name: Build Artifacts
+        run: build/artifacts.sh $GH_TAG
+      # https://github.com/marketplace/actions/upload-a-build-artifact
+      - uses: actions/upload-artifact@v4
+        with:
+          name: binaries
+          path: bin/artifacts/
+
+  release:
+    name: Release
+    runs-on: ubuntu-latest
+    needs: [build-release-binaries]
+    steps:
+      # https://github.com/actions/checkout
+      - uses: actions/checkout@v4
+      # https://github.com/actions/download-artifact
+      - uses: actions/download-artifact@v4
+        with:
+          name: binaries
+          path: bin/artifacts/
+      - name: Create Release
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: build/release.sh $GH_TAG
+

build/README.md

@@ -0,0 +1,25 @@
+# Building a Release
+
+## Git Tags
+
+Github workflows has been configured in such a way that simply pushing a tag will deploy a new version of Piko.
+
+```
+git tag v<TAG>
+git push origin --tags
+```
+
+This will kick off the "Release" workflow on Github.
+
+## Github Releases
+
+New releases may also be built using the Github GUI. From the releases page:
+
+1. Draft a new release
+1. Create your new tag under "Choose a tag", choosing "Create new tag <TAG> on publish"
+1. Create your release notes or choose "Generate release notes"
+1. Give your release a title.
+1. Click Publish.
+
+This will generate a new git tag with the tag you've created. It will run the github action to build the artifacts and will then overwrite the release with a new release which contains the binaries attached.
+

build/artifacts.sh

@@ -1,4 +1,9 @@
 #!/bin/bash
+set -euo pipefail
+
+# Set the VERSION to $1, otherwise get it from `git describe`
+GIT_VERSION=$(git describe || echo "NONE")
+VERSION="${1:-$GIT_VERSION}"
 
 declare -a arr=(
 	"linux/amd64"
@@ -11,7 +16,6 @@ mkdir -p bin/artifacts
 
 for i in "${arr[@]}"
 do
-	VERSION=$(git describe)
 	GOOSARCH=$i
 	GOOS=${GOOSARCH%/*}
 	GOARCH=${GOOSARCH#*/}

build/release.sh

@@ -0,0 +1,29 @@
+#!/bin/bash
+
+set -euo pipefail
+
+if [ $# -ne 1 ]; then
+  echo "No release tag name given. Failing"
+  exit 1
+fi
+
+
+if ! command -v gh 2>&1 >/dev/null
+then
+  echo "Github CLI could not be found"
+  exit 2
+fi
+
+if gh release edit $1 --verify-tag ;
+then
+  # Release exists, upload binaries
+  gh release upload \
+    $1 \
+    bin/artifacts/*
+else
+  gh release create \
+    $1 \
+    bin/artifacts/* \
+    --generate-notes
+fi
+