Initial commit: stalwart-migrator design and scaffolding

In-place upgrade tool for Stalwart Mail Server (0.15.5 -> latest) with checkpointed rollback and post-migration validation. Design stage; see ARCHITECTURE.md.
2026-08-22 18:17:17 -07:00
commit 719a945d64
71 changed files with 6677 additions and 0 deletions
@@ -0,0 +1,78 @@
+package preflight
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"os/exec"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+// semver is a minimal major.minor.patch version - enough for this tool's
+// comparisons since Stalwart's pre-1.0 release tags don't use pre-release
+// or build metadata.
+type semver struct {
+	Major, Minor, Patch int
+}
+
+var versionPattern = regexp.MustCompile(`v?(\d+)\.(\d+)\.(\d+)`)
+
+func parseSemver(s string) (semver, error) {
+	m := versionPattern.FindStringSubmatch(s)
+	if m == nil {
+		return semver{}, fmt.Errorf("preflight: no version number found in %q", s)
+	}
+	major, _ := strconv.Atoi(m[1])
+	minor, _ := strconv.Atoi(m[2])
+	patch, _ := strconv.Atoi(m[3])
+	return semver{major, minor, patch}, nil
+}
+
+func (v semver) String() string { return fmt.Sprintf("%d.%d.%d", v.Major, v.Minor, v.Patch) }
+
+// Compare returns -1, 0, or 1 as v is less than, equal to, or greater than o.
+func (v semver) Compare(o semver) int {
+	if v.Major != o.Major {
+		return cmp(v.Major, o.Major)
+	}
+	if v.Minor != o.Minor {
+		return cmp(v.Minor, o.Minor)
+	}
+	return cmp(v.Patch, o.Patch)
+}
+
+func cmp(a, b int) int {
+	switch {
+	case a < b:
+		return -1
+	case a > b:
+		return 1
+	default:
+		return 0
+	}
+}
+
+// minSupportedSource is the oldest version this tool will start a migration
+// from. Stalwart's own upgrade guidance says older installs need to reach
+// 0.15.x first before crossing the 0.15/0.16 schema boundary this tool
+// automates - see ARCHITECTURE.md §1/§4.1.
+var minSupportedSource = semver{0, 15, 0}
+
+// DetectVersion runs the installed binary's --version flag and extracts a
+// semver from its output.
+func DetectVersion(ctx context.Context, binaryPath string) (string, error) {
+	cmd := exec.CommandContext(ctx, binaryPath, "--version")
+	var out bytes.Buffer
+	cmd.Stdout = &out
+	cmd.Stderr = &out
+	if err := cmd.Run(); err != nil {
+		return "", fmt.Errorf("preflight: run %s --version: %w (output: %s)", binaryPath, err, strings.TrimSpace(out.String()))
+	}
+	v, err := parseSemver(out.String())
+	if err != nil {
+		return "", fmt.Errorf("preflight: parse version from %s --version output %q: %w", binaryPath, strings.TrimSpace(out.String()), err)
+	}
+	return v.String(), nil
+}