PRODENG-3471: fix Windows MCR install for FIPS channels

For FIPS channels (e.g. stable-29.2.1/fips) the Windows MCR installer
repo publishes versioned artifacts (docker-29.2.1+fips.zip) but does
NOT publish docker-latest+fips.zip.  Launchpad was hardcoding
DOCKER_VERSION=latest, which caused the installer to construct a
non-existent URL and exit 1 on all Windows nodes.

Linux nodes were unaffected because the Linux installers use
package-manager channels, not this download URL.

Fix: add MCRConfig.WindowsInstallerVersion() which returns 'latest'
for all non-FIPS channels (preserving current behaviour — only
docker-latest.zip is published for non-FIPS) and extracts the version
from the channel string for FIPS channels:
  stable-29.2.1/fips  → 29.2.1
  stable-29.4.1/fips  → 29.4.1
  test-29.4.1-rc3/fips → 29.4.1-rc3

The installer script appends +fips automatically when CHANNEL contains
/fips, so only the numeric version needs to be supplied.

Note: the ticket's proposed Version() method extracted the version for
all versioned channels (e.g. stable-29.2 → 29.2), which would break
non-FIPS installs since docker-29.2.zip is not published.
WindowsInstallerVersion() guards on the /fips suffix to avoid this.

Signed-off-by: James Nesbitt <jnesbitt@mirantis.com>

Author: james-nesbitt

pkg/configurer/windows.go

@@ -60,7 +60,7 @@ func (c WindowsConfigurer) InstallMCRLicense(h os.Host, lic string) error {
 
 // InstallMCR install MCR on Windows.
 func (c WindowsConfigurer) InstallMCR(h os.Host, engineConfig commonconfig.MCRConfig) error {
-	version := "latest"
+	version := engineConfig.WindowsInstallerVersion()
 
 	installerPath, getInstallerErr := GetInstaller(engineConfig.InstallURLWindows)
 	if getInstallerErr != nil {

pkg/product/common/config/mcr_config.go

@@ -1,6 +1,8 @@
 package config
 
 import (
+	"strings"
+
 	"github.com/Mirantis/launchpad/pkg/constant"
 )
 
@@ -70,3 +72,35 @@ func (c *MCRConfig) SetDefaults() {
 		c.InstallURLWindows = constant.MCRInstallURLWindows
 	}
 }
+
+// WindowsInstallerVersion returns the version token to pass as DOCKER_VERSION
+// to the Windows MCR installer script (install.ps1).
+//
+// For non-FIPS channels (e.g. "stable-29.2", "stable-25.0") the installer
+// repo publishes only a single "docker-latest.zip" artifact, so "latest" is
+// always correct.
+//
+// For FIPS channels (e.g. "stable-29.2.1/fips") the repo publishes versioned
+// artifacts ("docker-29.2.1+fips.zip") but NOT a "docker-latest+fips.zip",
+// so the version must be extracted from the channel string.  The installer
+// script appends "+fips" automatically when it detects the /fips suffix in
+// CHANNEL, so we only need to supply the numeric version here.
+func (c *MCRConfig) WindowsInstallerVersion() string {
+	if !strings.HasSuffix(c.Channel, "/fips") {
+		return "latest"
+	}
+	// Strip the /fips suffix, then walk the dash-separated parts looking for
+	// the first segment that starts with a digit — that is the version.
+	// e.g. "stable-29.2.1/fips" → "stable-29.2.1" → ["stable","29.2.1"] → "29.2.1"
+	// e.g. "test-29.4.1-rc3/fips" → "test-29.4.1-rc3" → ["test","29.4.1-rc3"] → "29.4.1-rc3"
+	ch := strings.TrimSuffix(c.Channel, "/fips")
+	parts := strings.Split(ch, "-")
+	for i, p := range parts {
+		if len(p) > 0 && p[0] >= '0' && p[0] <= '9' {
+			return strings.Join(parts[i:], "-")
+		}
+	}
+	// FIPS channel with no parseable version — fall back to latest and let the
+	// installer fail with a clear error rather than silently downloading wrong.
+	return "latest"
+}

pkg/product/common/config/mcr_config_test.go

@@ -30,3 +30,30 @@ func TestSwarmUpdateCommands(t *testing.T) {
 	require.Equal(t, 1, slices.Index(cfg.SwarmUpdateCommands, "command2"))
 	require.Equal(t, 2, slices.Index(cfg.SwarmUpdateCommands, "command3"))
 }
+
+func TestWindowsInstallerVersion(t *testing.T) {
+	tests := []struct {
+		channel string
+		want    string
+	}{
+		// Standard channels — always "latest" regardless of minor version
+		{"stable-29.2", "latest"},
+		{"stable-25.0", "latest"},
+		{"ee-stable-29.2", "latest"},
+		// FIPS channels — version extracted from channel string
+		{"stable-29.2.1/fips", "29.2.1"},
+		{"stable-29.4.1/fips", "29.4.1"},
+		{"test-29.4.1/fips", "29.4.1"},
+		// FIPS RC channel — full version including rc suffix
+		{"test-29.4.1-rc3/fips", "29.4.1-rc3"},
+		// FIPS channel with no version — falls back to latest
+		{"stable/fips", "latest"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.channel, func(t *testing.T) {
+			cfg := commonconfig.MCRConfig{Channel: tt.channel}
+			got := cfg.WindowsInstallerVersion()
+			require.Equal(t, tt.want, got, "channel=%q", tt.channel)
+		})
+	}
+}