(#256) CI: fix Docker tagging

General approach copied from https://github.com/ForNeVeR/fornever.me

.github/workflows/docker.yml

@@ -19,15 +19,13 @@ jobs:
   publish:
     runs-on: ubuntu-22.04
     steps:
-      - name: Extract metadata for Docker
-        if: github.event_name == 'push' && contains(github.ref, 'refs/tags/')
-        id: meta
-        uses: docker/metadata-action@v5
-        with:
-          images: |
-            codingteam/emulsion
-          tags: |
-            type=ref,event=branch
+      - name: Clone the repository
+        uses: actions/checkout@v4
+
+      - name: Read version from ref
+        id: version
+        shell: pwsh
+        run: echo "version=$(./scripts/Get-Version.ps1 -RefName $env:GITHUB_REF)" >> $env:GITHUB_OUTPUT
 
       - name: Login to Docker Hub
         if: github.event_name == 'push' && contains(github.ref, 'refs/tags/')
@@ -39,7 +37,5 @@ jobs:
       - name: Build and Push Docker Images
         uses: docker/build-push-action@v6
         with:
-          tags: |
-            ${{ steps.meta.outputs.tags }}
-            codingteam/emulsion:latest
+          tags: codingteam/emulsion:latest,codingteam/emulsion:v${{ steps.version.outputs.version }}
           push: ${{ github.event_name == 'push' && contains(github.ref, 'refs/tags/') && 'true' || 'false' }}

Emulsion.sln

@@ -68,6 +68,7 @@ EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "scripts", "scripts", "{E3091B22-752A-4260-B4F3-903B9043479F}"
 	ProjectSection(SolutionItems) = preProject
 		scripts\Test-Encoding.ps1 = scripts\Test-Encoding.ps1
+		scripts\Get-Version.ps1 = scripts\Get-Version.ps1
 	EndProjectSection
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "LICENSES", "LICENSES", "{BBA60ACE-9FB4-4F3B-89EC-16A5BB9F5686}"

scripts/Get-Version.ps1

@@ -0,0 +1,25 @@
+# SPDX-FileCopyrightText: 2024 Friedrich von Never <[email protected]>
+#
+# SPDX-License-Identifier: MIT
+
+param(
+    [string] $RefName,
+    [string] $RepositoryRoot = "$PSScriptRoot/..",
+
+    $ProjectFile = "$RepositoryRoot/Emulsion/Emulsion.fsproj"
+)
+
+$ErrorActionPreference = 'Stop'
+Set-StrictMode -Version Latest
+
+Write-Host "Determining version from ref `"$RefName`"…"
+if ($RefName -match '^refs/tags/v') {
+    $version = $RefName -replace '^refs/tags/v', ''
+    Write-Host "Pushed ref is a version tag, version: $version"
+} else {
+    [xml] $props = Get-Content $ProjectFile
+    $version = $props.Project.PropertyGroup.Version
+    Write-Host "Pushed ref is a not version tag, get version from $($ProjectFile): $version"
+}
+
+Write-Output $version