Windows support

.github/workflows/test.yml

@@ -12,17 +12,32 @@ on:
 permissions:
   contents: read
 
+env:
+  CACHE_BUST: v2
+
 jobs:
-  build-with-snapshot:
-    name: Build with Snapshot
-    runs-on: runs-on=${{ github.run_id }}/image=ubuntu24-full-x64/family=c7a.2xlarge
+  test-linux-with-save-docker:
+    name: Test Linux with save (docker)
+    runs-on: runs-on=${{ github.run_id }}/image=ubuntu24-full-x64/family=c7a.xlarge
     steps:
-      - uses: actions/checkout@v4
-      - uses: ./
+      - uses: actions/checkout@v5
+      - name: snapshot
+        id: snapshot
+        uses: ./
         with:
+          version: ${{ env.CACHE_BUST }}-${{ github.job }}
           path: /var/lib/docker
           volume_size: 60
+      - name: Check test file exists if cache hit
+        if: steps.snapshot.outputs.cache-hit == 'true'
+        run: |
+          test -f /var/lib/docker/test-file.txt || (echo "Error: test-file.txt should exist when cache-hit is true" && exit 1)
+          echo "✓ test-file.txt exists as expected"
       - run: df -ah && sudo ls -al /var/lib/docker
+      - name: Create test file
+        run: |
+          echo "Test file created at $(date)" | sudo tee /var/lib/docker/test-file.txt
+          sudo ls -lh /var/lib/docker/test-file.txt
       - uses: docker/setup-buildx-action@v3
         with:
           name: runs-on
@@ -32,21 +47,133 @@ jobs:
           repository: runs-on-demo/benchmark-posthog
           submodules: recursive
           path: repo
+      - name: Determine upstream commit SHA
+        id: upstream
+        run: echo "sha=$(cd repo/upstream && git rev-parse HEAD)" >> $GITHUB_OUTPUT
       - uses: docker/build-push-action@v4
         with:
-          context: ./repo/upstream
+          context: https://github.com/PostHog/posthog.git#${{ steps.upstream.outputs.sha }}
+          build-args: |
+            BUILDKIT_CONTEXT_KEEP_GIT_DIR=1
 
-  restore-only:
-    name: "save: false"
-    runs-on: runs-on=${{ github.run_id }}/image=ubuntu24-full-x64/family=c7a.2xlarge
+  test-linux-with-save-simple:
+    name: Test Linux with save (simple)
+    runs-on: runs-on=${{ github.run_id }}/image=ubuntu24-full-x64/family=c7a.large
     steps:
-      - uses: actions/checkout@v4
-      - uses: ./
+      - uses: actions/checkout@v5
+      - name: snapshot
+        id: snapshot
+        uses: ./
         with:
+          version: ${{ env.CACHE_BUST }}-${{ github.job }}
+          path: /path/to/volume
+          volume_throughput: 125
+          volume_size: 5
+      - name: Check test file exists if cache hit
+        if: steps.snapshot.outputs.cache-hit == 'true'
+        run: |
+          test -f /path/to/volume/test-file.txt || (echo "Error: test-file.txt should exist when cache-hit is true" && exit 1)
+          echo "✓ test-file.txt exists as expected"
+      - name: Create test file
+        run: |
+          echo "Test file created at $(date)" | sudo tee /path/to/volume/test-file.txt
+          sudo ls -lh /path/to/volume/test-file.txt
+
+  test-linux-no-save:
+    name: Test Linux without save
+    runs-on: runs-on=${{ github.run_id }}/image=ubuntu24-full-x64/family=c7a.large
+    steps:
+      - uses: actions/checkout@v5
+      - name: snapshot
+        id: snapshot
+        uses: ./
+        with:
+          version: ${{ env.CACHE_BUST }}-${{ github.job }}-v2
           path: /path/to/volume
           volume_size: 10
           save: false
       - run: |
-          sudo chown -R runner:runner /path/to/volume
           dd if=/dev/zero of=/path/to/volume/test-file-1gb bs=1M count=1024
           ls -lh /path/to/volume/
+
+  test-windows-with-save:
+    name: Test Windows with save
+    runs-on: runs-on=${{ github.run_id }}/image=windows25-full-x64/family=m7a.large
+    steps:
+      - uses: actions/checkout@v5
+      - name: snapshot
+        id: snapshot
+        uses: ./
+        with:
+          version: ${{ env.CACHE_BUST }}-${{ github.job }}
+          path: C:\test-volume
+          volume_size: 10
+          save: true
+      - name: Check test file exists if cache hit
+        if: steps.snapshot.outputs.cache-hit == 'true'
+        shell: pwsh
+        run: |
+          $testFile = "C:\test-volume\test-file.txt"
+          if (Test-Path $testFile) {
+            Write-Host "✓ test-file.txt exists as expected"
+            Get-Item $testFile | Format-List FullName, Length, LastWriteTime
+            Write-Host "File contents:"
+            Get-Content $testFile
+          } else {
+            Write-Error "Error: test-file.txt should exist when cache-hit is true"
+            exit 1
+          }
+      - name: Display all disks and mountpoints
+        shell: pwsh
+        run: |
+          Write-Host "=== All Disks ==="
+          Get-Disk | Format-Table Number, PartitionStyle, OperationalStatus, Size, FriendlyName -AutoSize
+          Write-Host "`n=== All Partitions ==="
+          Get-Partition | Format-Table DiskNumber, PartitionNumber, DriveLetter, AccessPaths, Size -AutoSize
+          Write-Host "`n=== All Volumes ==="
+          Get-Volume | Format-Table DriveLetter, FileSystemLabel, FileSystem, Size, SizeRemaining -AutoSize
+          Write-Host "`n=== Mount Points ==="
+          Get-Partition | Where-Object { $_.AccessPaths } | ForEach-Object {
+            Write-Host "Disk $($_.DiskNumber), Partition $($_.PartitionNumber):"
+            $_.AccessPaths | ForEach-Object { Write-Host "  $_" }
+          }
+      - name: Test write to mounted volume
+        shell: pwsh
+        run: |
+          $testFile = "C:\test-volume\test-file.txt"
+          $testContent = "Test file written at $(Get-Date -Format 'yyyy-MM-dd HH:mm:ss')"
+          Write-Host "Writing test file to $testFile"
+          Set-Content -Path $testFile -Value $testContent
+          Write-Host "File written successfully"
+          Write-Host "`n=== Verifying file ==="
+          Get-Item $testFile | Format-List FullName, Length, LastWriteTime
+          Write-Host "File contents:"
+          Get-Content $testFile
+          Write-Host "`n=== Directory listing ==="
+          Get-ChildItem C:\test-volume | Format-Table Name, Length, LastWriteTime -AutoSize
+
+  test-windows-no-save:
+    name: Test Windows without save
+    runs-on: runs-on=${{ github.run_id }}/image=windows25-full-x64/family=m7a.large
+    steps:
+      - uses: actions/checkout@v5
+      - uses: ./
+        with:
+          version: ${{ env.CACHE_BUST }}-${{ github.job }}
+          path: C:\test-volume
+          volume_size: 10
+          save: false
+      - name: Display all disks and mountpoints
+        shell: pwsh
+        run: |
+          Write-Host "=== All Disks ==="
+          Get-Disk | Format-Table Number, PartitionStyle, OperationalStatus, Size, FriendlyName -AutoSize
+          Write-Host "`n=== All Partitions ==="
+          Get-Partition | Format-Table DiskNumber, PartitionNumber, DriveLetter, AccessPaths, Size -AutoSize
+          Write-Host "`n=== All Volumes ==="
+          Get-Volume | Format-Table DriveLetter, FileSystemLabel, FileSystem, Size, SizeRemaining -AutoSize
+          Write-Host "`n=== Mount Points ==="
+          Get-Partition | Where-Object { $_.AccessPaths } | ForEach-Object {
+            Write-Host "Disk $($_.DiskNumber), Partition $($_.PartitionNumber):"
+            $_.AccessPaths | ForEach-Object { Write-Host "  $_" }
+          }

Makefile

@@ -7,7 +7,9 @@ help:
 	@echo '   make js                    Generate `index.js` and `post.js` files'
 	@echo '   make main-linux-amd64      Build static binary for linux/amd64'
 	@echo '   make main-linux-arm64      Build static binary for linux/arm64'
+	@echo '   make main-windows-amd64    Build static binary for windows/amd64'
 	@echo '   make build	             Build all static binaries + `index.js` and `post.js`'
+	@echo '   make test                  Run all tests'
 	@echo ''
 
 UPX_BIN := $(shell command -v upx 2> /dev/null)
@@ -31,8 +33,14 @@ main-linux-arm64: _require-upx
 	CGO_ENABLED=0 GOOS=linux GOARCH=arm64 go build -ldflags="-s -w" -installsuffix static -o "main-linux-arm64" $(COMMAND)
 	upx -q -9 "main-linux-arm64"
 
+.PHONY: main-windows-amd64
+main-windows-amd64: _require-upx
+	rm -f main-windows-amd64.exe
+	CGO_ENABLED=0 GOOS=windows GOARCH=amd64 go build -ldflags="-s -w" -installsuffix static -o "main-windows-amd64.exe" $(COMMAND)
+	upx -q -9 "main-windows-amd64.exe"
+
 .PHONY: build
-build: main-linux-amd64 main-linux-arm64 js
+build: main-linux-amd64 main-linux-arm64 main-windows-amd64 js
 
 .PHONY: _require-upx
 _require-upx:
@@ -54,4 +62,8 @@ release: tag
 	gh release create $(TAG) --generate-notes
 
 upgrade:
-	mise exec -- go get -u -t ./...
+	mise exec -- go get -u -t ./...
+
+.PHONY: test
+test:
+	mise exec -- go test ./...

README.md

@@ -39,10 +39,32 @@ jobs:
 | volume_initialization_rate | Initialization rate to use for the volume. Useful for very large volumes. 100 MB/s - 200 MB/s: $0.00240/GB, 201 MB/s - 300 MB/s $0.00360/GB | No | 0 |
 | wait_for_completion | Wait for snapshot completion before exiting. Note that the first snapshot will always be waited for | No | false |
 | save | Save the volume in the post step. When false, the volume is not saved, only restored | No | true |
+| key | Custom snapshot key used to segregate snapshots. Defaults to `${{ github.ref_name }}-${{ github.ref }}` | No | auto |
+| restore-keys | Multi-line list of fallback snapshot key prefixes, evaluated top-to-bottom. Defaults to `${{ github.ref_name }}-` and `${{ github.default_branch }}-` | No | auto |
 
 ## Snapshot selection
 
-When restoring a snapshot, the most recent snapshot for the current branch is fetched. If none is found, the most recent snapshot for the repository default branch will be taken. If none found, a new empty volume is used instead.
+Snapshot lookup now mirrors GitHub's cache action semantics:
+
+1. Try the exact `key`.
+2. Fall back through each `restore-keys` prefix (latest snapshot whose key starts with the prefix).
+3. As a compatibility fallback, use the latest snapshot for the current branch, then the repository default branch.
+4. If there's still no match, create a new empty volume.
+
+This keeps the legacy branch-based behavior working while enabling deterministic cache keys for large directories.
+
+### Example: isolation with custom keys
+
+```yaml
+- name: Unity Library Snapshot
+  uses: runs-on/snapshot@v1
+  with:
+    path: ${{ github.workspace }}/Library
+    key: unity-library-${{ hashFiles('Packages/manifest.json') }}
+    restore-keys: |
+      unity-library-${{ github.ref_name }}-
+      unity-library-
+```
 
 ## Snapshot cleanup
 

action.yml

@@ -43,3 +43,15 @@ inputs:
     description: 'Save the volume in the post step. When false, the volume is not saved.'
     required: false
     default: 'true'
+  key:
+    description: 'Custom snapshot key. Defaults to github.ref_name-github.ref when unset.'
+    required: false
+    default: ''
+  restore-keys:
+    description: 'Multiline list of fallback snapshot key prefixes (one per line). Defaults to github.ref_name- and github.default_branch- prefixes.'
+    required: false
+    default: ''
+
+outputs:
+  cache-hit:
+    description: 'Whether the volume was restored from an existing snapshot (true) or created as a new volume (false).'

index.js

@@ -1,8 +1,9 @@
 const childProcess = require('child_process')
 const os = require('os')
 const process = require('process')
+const path = require('path')
 
-const ARGS = ''.split(',')
+const ARGS = ''.split(',').filter(arg => arg !== '')
 const WINDOWS = 'win32'
 const LINUX = 'linux'
 const AMD64 = 'x64'
@@ -19,21 +20,18 @@ function chooseBinary() {
         return `main-linux-arm64`
     }
     if (platform === WINDOWS && arch === AMD64) {
-        return `main-windows-amd64`
+        return `main-windows-amd64.exe`
     }
 
     console.error(`Unsupported platform (${platform}) and architecture (${arch})`)
-    process.exit(1)
+    process.exit(0)
 }
 
 function main() {
     const binary = chooseBinary()
-    const mainScript = `${__dirname}/${binary}`
+    const mainScript = path.join(__dirname, binary)
     if (os.platform() === WINDOWS) {
-        childProcess.execFileSync('powershell', [
-            '-Command',
-            `Start-Process -FilePath "${mainScript}" -ArgumentList "${ARGS.join(' ')}" -Verb RunAs -WindowStyle Hidden -Wait`
-        ], { stdio: 'inherit' })
+        childProcess.execFileSync(mainScript, ARGS, { stdio: 'inherit' })
     } else {
         childProcess.execFileSync('sudo', ['-n', '-E', mainScript, ...ARGS], { stdio: 'inherit' })
     }

index.template.js

@@ -1,8 +1,9 @@
 const childProcess = require('child_process')
 const os = require('os')
 const process = require('process')
+const path = require('path')
 
-const ARGS = '{{ .Args }}'.split(',')
+const ARGS = '{{ .Args }}'.split(',').filter(arg => arg !== '')
 const WINDOWS = 'win32'
 const LINUX = 'linux'
 const AMD64 = 'x64'
@@ -19,21 +20,18 @@ function chooseBinary() {
         return `main-linux-arm64`
     }
     if (platform === WINDOWS && arch === AMD64) {
-        return `main-windows-amd64`
+        return `main-windows-amd64.exe`
     }
 
     console.error(`Unsupported platform (${platform}) and architecture (${arch})`)
-    process.exit(1)
+    process.exit(0)
 }
 
 function main() {
     const binary = chooseBinary()
-    const mainScript = `${__dirname}/${binary}`
+    const mainScript = path.join(__dirname, binary)
     if (os.platform() === WINDOWS) {
-        childProcess.execFileSync('powershell', [
-            '-Command',
-            `Start-Process -FilePath "${mainScript}" -ArgumentList "${ARGS.join(' ')}" -Verb RunAs -WindowStyle Hidden -Wait`
-        ], { stdio: 'inherit' })
+        childProcess.execFileSync(mainScript, ARGS, { stdio: 'inherit' })
     } else {
         childProcess.execFileSync('sudo', ['-n', '-E', mainScript, ...ARGS], { stdio: 'inherit' })
     }