feat: runtime manager

rtmanager/internal/adapters/redisstate/gamelease/store.go

@@ -0,0 +1,117 @@
+// Package gamelease implements the Redis-backed adapter for
+// `ports.GameLeaseStore`.
+//
+// The lease guards every lifecycle operation Runtime Manager runs
+// against one game (start, stop, restart, patch, cleanup, plus the
+// reconciler's drift mutations). Acquisition uses `SET NX PX <ttl>`
+// with a random caller token; release runs a Lua compare-and-delete
+// so a holder that lost the lease through TTL expiry cannot wipe
+// another caller's claim.
+package gamelease
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strings"
+	"time"
+
+	"galaxy/rtmanager/internal/adapters/redisstate"
+	"galaxy/rtmanager/internal/ports"
+
+	"github.com/redis/go-redis/v9"
+)
+
+// releaseScript removes the per-game lease only when the supplied token
+// still owns it. Compare-and-delete prevents a TTL-expired holder from
+// clearing another caller's claim.
+var releaseScript = redis.NewScript(`
+if redis.call("GET", KEYS[1]) == ARGV[1] then
+	return redis.call("DEL", KEYS[1])
+end
+return 0
+`)
+
+// Config configures one Redis-backed game lease store instance. The
+// store does not own the redis client lifecycle; the caller (typically
+// the service runtime) opens and closes it.
+type Config struct {
+	// Client stores the Redis client the store uses for every command.
+	Client *redis.Client
+}
+
+// Store persists the per-game lifecycle lease in Redis.
+type Store struct {
+	client *redis.Client
+	keys   redisstate.Keyspace
+}
+
+// New constructs one Redis-backed game lease store from cfg.
+func New(cfg Config) (*Store, error) {
+	if cfg.Client == nil {
+		return nil, errors.New("new rtmanager game lease store: nil redis client")
+	}
+	return &Store{
+		client: cfg.Client,
+		keys:   redisstate.Keyspace{},
+	}, nil
+}
+
+// TryAcquire attempts to acquire the per-game lease for gameID owned by
+// token for ttl. The acquired return is true on a successful claim and
+// false when another caller still owns the lease. A non-nil error
+// reports a transport failure and must not be confused with a missed
+// lease.
+func (store *Store) TryAcquire(ctx context.Context, gameID, token string, ttl time.Duration) (bool, error) {
+	if store == nil || store.client == nil {
+		return false, errors.New("try acquire game lease: nil store")
+	}
+	if ctx == nil {
+		return false, errors.New("try acquire game lease: nil context")
+	}
+	if strings.TrimSpace(gameID) == "" {
+		return false, errors.New("try acquire game lease: game id must not be empty")
+	}
+	if strings.TrimSpace(token) == "" {
+		return false, errors.New("try acquire game lease: token must not be empty")
+	}
+	if ttl <= 0 {
+		return false, errors.New("try acquire game lease: ttl must be positive")
+	}
+
+	acquired, err := store.client.SetNX(ctx, store.keys.GameLease(gameID), token, ttl).Result()
+	if err != nil {
+		return false, fmt.Errorf("try acquire game lease: %w", err)
+	}
+	return acquired, nil
+}
+
+// Release removes the per-game lease for gameID only when token still
+// matches the stored owner value. A token mismatch is a silent no-op.
+func (store *Store) Release(ctx context.Context, gameID, token string) error {
+	if store == nil || store.client == nil {
+		return errors.New("release game lease: nil store")
+	}
+	if ctx == nil {
+		return errors.New("release game lease: nil context")
+	}
+	if strings.TrimSpace(gameID) == "" {
+		return errors.New("release game lease: game id must not be empty")
+	}
+	if strings.TrimSpace(token) == "" {
+		return errors.New("release game lease: token must not be empty")
+	}
+
+	if err := releaseScript.Run(
+		ctx,
+		store.client,
+		[]string{store.keys.GameLease(gameID)},
+		token,
+	).Err(); err != nil {
+		return fmt.Errorf("release game lease: %w", err)
+	}
+	return nil
+}
+
+// Compile-time assertion: Store implements ports.GameLeaseStore.
+var _ ports.GameLeaseStore = (*Store)(nil)