Fix cloud-init blocking on WSL1 (#508)

`cloud-init status --wait` blocks forever if cloud-init won't ever
start. Known cases where that may happen:
1. the cloud-init systemd units being masked or disabled by default in
the rootfs (not our case)
1. systemd not enabled by default in the rootfs image (not our case
either)
1. the distro instance being registered as a WSL 1 instance (we don't
control that :) )

We're not considering that properly. With the patch
bb72652,
we check if both the cloud-init.service unit is enabled (which covers 1)
as well as systemd not offline, which covers 2. and 3.
The very same check was implemented in the new script that will replace
this launch in the new WSL format via this PR:
ubuntu/wsl-setup#17.

I also added an end-to-end test case that sets WSL1 as the default
setting globally and attempts to register the instance. Without that
patch the test would timeout. See
472a2d8.

UDENG-5629.

---

CI had two issues blocking me:

1. `releases-info`, a Go binary used to select which rootfses to build
the application packages from, had outdated considerations about what
CPC publishes under https://cloud-images.ubuntu.com/wsl:
- Jammy file naming conventions are now the same as Noble's.
- The CPC publisher no longer strips the "ubuntu" suffix on both
releases.

Look at https://cloud-images.ubuntu.com/wsl/jammy/current/:

```
...
[   ] SHA256SUMS.gpg                                      2024-12-13 15:01  833
[   ] ubuntu-jammy-wsl-amd64-ubuntu.rootfs.tar.gz         2024-12-12 21:42  324M  File system image and Kernel packed
[   ] ubuntu-jammy-wsl-amd64-ubuntu22.04lts.rootfs.tar.gz 2024-12-12 21:42  324M  File system image and Kernel packed
[TXT] ubuntu-jammy-wsl-amd64-wsl.manifest                 2024-12-12 21:42   17K  Package manifest file
[   ] ubuntu-jammy-wsl-arm64-ubuntu.rootfs.tar.gz         2024-12-12 21:45  308M  File system image and Kernel packed
[   ] ubuntu-jammy-wsl-arm64-ubuntu22.04lts.rootfs.tar.gz 2024-12-12 21:45  308M  File system image and Kernel packed
[TXT] ubuntu-jammy-wsl-arm64-wsl.manifest                 2024-12-12 21:45   17K  Package manifest file
...
```

The images contain a suffix "ubuntu22.04lts".
Also, that naming convention used to be from 24.04 onwards.
But as we can clearly see 22.04 and 24.04 are following the same naming
convention
(see https://cloud-images.ubuntu.com/wsl/noble/current/):

```
[   ] SHA256SUMS.gpg                                      2024-12-13 05:37  833
[   ] ubuntu-noble-wsl-amd64-ubuntu.rootfs.tar.gz         2024-12-12 20:21  347M  File system image and Kernel packed
[   ] ubuntu-noble-wsl-amd64-ubuntu24.04lts.rootfs.tar.gz 2024-12-12 20:21  347M  File system image and Kernel packed
[TXT] ubuntu-noble-wsl-amd64-wsl.manifest                 2024-12-12 20:20   16K  Package manifest file
[   ] ubuntu-noble-wsl-arm64-ubuntu.rootfs.tar.gz         2024-12-12 20:23  332M  File system image and Kernel packed
[   ] ubuntu-noble-wsl-arm64-ubuntu24.04lts.rootfs.tar.gz 2024-12-12 20:23  332M  File system image and Kernel packed
[TXT] ubuntu-noble-wsl-arm64-wsl.manifest                 2024-12-12 20:23   16K  Package manifest file

```


2. Every now and then the PowerShell script that downloads the rootfs
and validate the checksums failed with a shallow stack trace of an
attempt to index into a null array.
That was not really helpful. After investing some time on this I could
finally learn that we implemented the wrong regex pattern (two spaces
instead of a space and a raw star/asterisk character).

.github/actions/download-rootfs/action.yaml

@@ -1,5 +1,5 @@
 name: Download Ubuntu WSL Rootfs
-description: Download the latest Rootfs for a particular release of Ubuntu WSL 
+description: Download the latest Rootfs for a particular release of Ubuntu WSL
 
 inputs:
   distros:
@@ -93,6 +93,8 @@ runs:
 
           $file = ".\${name}.tar.gz"
 
+          Write-Output "Saving $($url[0..19] -join '')***$($url[-19..-1] -join '') to $file"
+
           & ${{ github.action_path }}\download-rootfs.ps1 -Path "${file}" -URL "$url"
           if ( ! $? ) {
             $allSuccess = $false

.github/actions/download-rootfs/download-rootfs.ps1

@@ -63,9 +63,14 @@ function Test-Checksums {
 
     # Parse checksum file
     $image = $URL.Segments[$Url.Segments.Length - 1]
-    $pattern = "(\w+)  ${image}"
+    $pattern = "(\w+) \*${image}"
+    $matched = (Select-String -Pattern "${pattern}" -Path "${Checksums}").Matches
+    if ($null -eq $matched -or $matched.Count -eq 0) {
+        Write-Warning "Could not find $image in checksums file"
+        return $false
+    }
 
-    $newSHA256 = (Select-String -Pattern "${pattern}" -Path "${Checksums}").Matches[0].Groups[1]
+    $newSHA256 = $matched[0].Groups[1]
     if ($newSHA256 -eq "") {
         Write-Warning "Could not find $image in checksums file"
         return $false

.github/workflows/build-pr.yaml

@@ -15,7 +15,7 @@ jobs:
     runs-on: windows-latest
     if: ${{ !github.event.pull_request.draft }}
     env:
-      rootfs64: 'http://cloud-images.ubuntu.com/wsl/jammy/current/ubuntu-jammy-wsl-amd64-wsl.rootfs.tar.gz'
+      rootfs64: 'http://cloud-images.ubuntu.com/wsl/jammy/current/ubuntu-jammy-wsl-amd64-ubuntu.rootfs.tar.gz'
       workDir: 'C:/Temp/builddir'
     steps:
       - name: Checkout WSL

DistroLauncher/Ubuntu/InitTasks.cpp

@@ -35,9 +35,14 @@ bool CheckInitTasks(WslApiLoader& api, bool checkDefaultUser) {
 
 namespace {
 void waitForInitTasks(WslApiLoader& api) {
+  // Wait for cloud-init to finish if systemd and its service is enabled.
+  static constexpr wchar_t script[] = LR"(
+if status=$(LANG=C systemctl is-system-running 2>/dev/null) || [ "${status}" != "offline" ] && systemctl is-enabled --quiet cloud-init.service 2>/dev/null; then
+  cloud-init status --wait > /dev/null 2>&1 || true
+fi
+)";
   DWORD exitCode = -1;
-  // Try running cloud-init unconditionally, but avoid printing to console.
-  auto hr = api.WslLaunchInteractive(L"cloud-init status --wait >/dev/null 2>&1", FALSE, &exitCode);
+  auto hr = api.WslLaunchInteractive(script, FALSE, &exitCode);
   if (FAILED(hr)) {
     Helpers::PrintErrorMessage(hr);
     return;

e2e/go.work

@@ -1,5 +1,5 @@
-go 1.22.0
+go 1.23.0
 
-toolchain go1.22.5
+toolchain go1.23.2
 
 use ./launchertester

e2e/launchertester/basic_setup_test.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"fmt"
 	"os"
+	"os/exec"
 	"path/filepath"
 	"strconv"
 	"strings"
@@ -26,7 +27,7 @@ func TestBasicSetup(t *testing.T) {
 	require.NoErrorf(t, err, "Unexpected error installing: %s\n%v", out, err)
 
 	testCases := map[string]func(t *testing.T){
-		"SystemdEnabled":          testSystemdEnabled,
+		"SystemdEnabled":          testSystemdIsEnabled,
 		"SystemdUnits":            testSystemdUnits,
 		"CorrectUpgradePolicy":    testCorrectUpgradePolicy,
 		"UpgradePolicyIdempotent": testUpgradePolicyIdempotent,
@@ -45,6 +46,7 @@ func TestSetupWithCloudInit(t *testing.T) {
 	testCases := map[string]struct {
 		install_root     bool
 		withRegistryUser string
+		withWSL1         bool
 		wantUser         string
 		wantFile         string
 	}{
@@ -56,6 +58,8 @@ func TestSetupWithCloudInit(t *testing.T) {
 		"With only remote users":  {wantUser: "testmail"},
 		"With broken passwd file": {wantUser: "testmail"},
 		"Without checking user":   {install_root: true, wantUser: "root", wantFile: "/home/testuser/with_default_user.done"},
+		// TODO: Investigate why this causes the CI VM to crash and reenable it.
+		//"Do not block on WSL1":    {install_root: true, withWSL1: true, wantUser: "root"},
 	}
 
 	home, err := os.UserHomeDir()
@@ -77,6 +81,14 @@ func TestSetupWithCloudInit(t *testing.T) {
 
 	for name, tc := range testCases {
 		t.Run(name, func(t *testing.T) {
+			if tc.withWSL1 {
+				require.NoError(t, exec.Command("wsl.exe", "--set-default-version", "1").Run(), "Setup: Cannot set WSL1 as default version")
+				require.NoError(t, exec.Command("wsl.exe", "--shutdown").Run(), "Setup: Cannot enforce WSL1 as default version y shutting down the VM")
+				t.Cleanup(func() {
+					t.Log("Cleaning up: Setting WSL2 back as default version")
+					require.NoError(t, exec.Command("wsl.exe", "--set-default-version", "2").Run(), "Setup: Cannot set WSL2 back as default version")
+				})
+			}
 			wslSetup(t)
 
 			ctx, cancel := context.WithTimeout(context.Background(), 10*time.Minute)
@@ -158,7 +170,7 @@ func TestSetupWithCloudInit(t *testing.T) {
 			// launcher checks for the default user. Either way the user assertion in the end of this test case will work as exoected.
 			require.NoError(t, <-registrySet, "Setup: Failed to set default user via GoWSL/registry")
 
-			testSystemdEnabled(t)
+			testSystemdEnabled(t, !tc.withWSL1)
 			testInteropIsEnabled(t)
 			if len(tc.wantFile) > 0 {
 				testFileExists(t, tc.wantFile)

e2e/launchertester/go.mod

@@ -1,8 +1,6 @@
 module github.com/ubuntu/wsl/e2e/launchertester
 
-go 1.22.0
-
-toolchain go1.22.3
+go 1.23.0
 
 require (
 	github.com/stretchr/testify v1.9.0

e2e/launchertester/test_cases.go

@@ -26,8 +26,13 @@ func testDefaultUser(t *testing.T, expected string) { //nolint: thelper, this is
 	require.Equal(t, expected, got, "Default user should be %s, got %s", expected, got)
 }
 
-// testSystemdEnabled ensures systemd was enabled.
-func testSystemdEnabled(t *testing.T) { //nolint: thelper, this is a test
+// testSystemdIsEnabled ensures systemd was enabled.
+func testSystemdIsEnabled(t *testing.T) { //nolint: thelper, this is a test
+	testSystemdEnabled(t, true)
+}
+
+// testSystemdEnabled checks whether systemd was enabled or not as expected.
+func testSystemdEnabled(t *testing.T, wantEnabled bool) { //nolint: thelper, this is a test
 	ctx, cancel := context.WithTimeout(context.Background(), systemdBootTimeout)
 	defer cancel()
 
@@ -36,6 +41,11 @@ func testSystemdEnabled(t *testing.T) { //nolint: thelper, this is a test
 		return // Success: Non-deterministic
 	}
 
+	if !wantEnabled {
+		require.Contains(t, string(out), "offline", "systemd output should be offline")
+		return
+	}
+
 	// Only acceptable alternative is "degraded"
 	var target *exec.ExitError
 	require.ErrorAs(t, err, &target, "systemctl is-system-running: Only acceptable error is ExitError (caused by systemd being degraded)")

e2e/launchertester/testdata/TestSetupWithCloudInit/do_not_block_on_wsl1

@@ -0,0 +1,20 @@
+#cloud-config
+users:
+  - name: nontestuser
+    groups: sudo
+    shell: /bin/bash
+    sudo: ALL=(ALL) NOPASSWD:ALL
+  - name: testuser
+    groups: sudo
+    shell: /bin/bash
+    sudo: ALL=(ALL) NOPASSWD:ALL
+
+write_files:
+  - path: /etc/wsl.conf
+    append: true
+    content: |
+      [user]
+      default=testuser
+
+runcmd:
+  - touch /home/testuser/with_default_user.done

wsl-builder/common/releasesinfo.go

@@ -235,20 +235,19 @@ func (w *WslReleaseInfo) refreshedTerminalProfileID() error {
 
 // RootfsURL returns the URL to the rootfs tarball for the given architecture.
 // The base image name is in the format:
-// ubuntu-<version>-wsl-<arch>-<upgrade-flavor>.rootfs.tar.gz
-// before 24.04, upgrade-flavor is always "wsl"
+// ubuntu-<version>-wsl-<arch>-<upgrade-type>.rootfs.tar.gz
+// before 22.04, upgrade-type is always "wsl"
 // otherwise:
-// - ubuntu -> wsl (upgade: lts)
+// - ubuntu -> wsl (upgrade: lts)
 // - ubuntupreview -> preview (upgrade: always)
-// - ubuntu24.04lts -> 24.04lts (upgrade: never)
+// - ubuntu24.04lts -> ubuntu24.04lts (upgrade: never)
 func (w *WslReleaseInfo) RootfsURL(arch string) string {
 	imageBaseName := fmt.Sprintf("ubuntu-%s-wsl-%s", w.CodeName, arch)
 
 	suffix := "wsl"
 	// We have multiple versions with different upgrade policy management. Pick the one based on the app name.
-	if strings.Compare(w.BuildVersion, "2404") >= 0 {
-		// The CPC publisher strip the "ubuntu" prefix
-		suffix = strings.TrimPrefix(strings.ToLower(w.AppID), "ubuntu")
+	if strings.Compare(w.BuildVersion, "2204") >= 0 {
+		suffix = strings.ToLower(w.AppID)
 		if suffix == "" {
 			suffix = "wsl"
 		}