feat(core): add naming, RCON, store, config, and image-build libraries

Foundational libraries: deterministic resource naming, the RCON client, the Postgres store with embedded SQL migrations, configuration loading, and container image-build helpers.

internal/naming/naming.go

@@ -0,0 +1,96 @@
+// Package naming enforces the portability and admission rules (spec §2, §22):
+// a server name matches ^[a-z0-9-]{3,32}$ and is non-reserved, and every
+// hostname must be a single label under the configured root_domain. The root
+// domain is never hardcoded — it is always supplied by config — so this package
+// stays free of any deployment-specific domain.
+package naming
+
+import (
+	"fmt"
+	"regexp"
+	"strings"
+)
+
+var (
+	serverNameRE = regexp.MustCompile(`^[a-z0-9-]{3,32}$`)
+	dnsLabelRE   = regexp.MustCompile(`^[a-z0-9]([a-z0-9-]{0,61}[a-z0-9])?$`)
+)
+
+// reserved subdomains/server names that users may not claim: proxy/lobby and
+// the platform's own faces.
+var reserved = map[string]struct{}{
+	"lobby":    {},
+	"admin":    {},
+	"panel":    {},
+	"api":      {},
+	"felis":    {},
+	"velocity": {},
+	"registry": {},
+	"internal": {},
+	"www":      {},
+}
+
+// ValidateServerName checks the §22 name rule and reservation list.
+func ValidateServerName(name string) error {
+	if !serverNameRE.MatchString(name) {
+		return fmt.Errorf("naming: invalid server name %q: must match ^[a-z0-9-]{3,32}$", name)
+	}
+	if strings.HasPrefix(name, "-") || strings.HasSuffix(name, "-") {
+		return fmt.Errorf("naming: server name %q must not start or end with '-'", name)
+	}
+	if _, ok := reserved[name]; ok {
+		return fmt.Errorf("naming: server name %q is reserved", name)
+	}
+	return nil
+}
+
+// IsReserved reports whether label is on the reserved list.
+func IsReserved(label string) bool {
+	_, ok := reserved[label]
+	return ok
+}
+
+// worldVolumeName mirrors operator.dataVolumeName: the per-server StatefulSet's
+// volumeClaimTemplate is named "world", so a single-replica server's world PVC
+// is "world-<name>-0". This is the one naming convention shared by the operator
+// (which creates the PVC), the reaper (which deletes it), and restore (which
+// mounts it), so it lives here rather than being duplicated per subsystem.
+const worldVolumeName = "world"
+
+// WorldPVCName returns the world PersistentVolumeClaim name for a server,
+// matching the operator's StatefulSet volumeClaimTemplate naming
+// ("world-<name>-0" for the sole replica).
+func WorldPVCName(server string) string {
+	return worldVolumeName + "-" + server + "-0"
+}
+
+// Hostname composes subdomain.rootDomain after validating the subdomain.
+func Hostname(subdomain, rootDomain string) (string, error) {
+	if err := ValidateServerName(subdomain); err != nil {
+		return "", err
+	}
+	if rootDomain == "" {
+		return "", fmt.Errorf("naming: root domain is empty")
+	}
+	return subdomain + "." + rootDomain, nil
+}
+
+// ValidateHostname enforces the §2 invariant that host is a single label
+// directly under rootDomain.
+func ValidateHostname(host, rootDomain string) error {
+	if rootDomain == "" {
+		return fmt.Errorf("naming: root domain is empty")
+	}
+	suffix := "." + rootDomain
+	if !strings.HasSuffix(host, suffix) {
+		return fmt.Errorf("naming: hostname %q must be under %q", host, rootDomain)
+	}
+	label := strings.TrimSuffix(host, suffix)
+	if label == "" || strings.Contains(label, ".") {
+		return fmt.Errorf("naming: hostname %q must be a single label under %q", host, rootDomain)
+	}
+	if !dnsLabelRE.MatchString(label) {
+		return fmt.Errorf("naming: invalid hostname label %q", label)
+	}
+	return nil
+}