[FEAT] Only implement used API of Redis client

- Currently for the `nosql` module (which simply said provides a manager
for redis clients) returns the
[`redis.UniversalClient`](https://pkg.go.dev/github.com/redis/go-redis/v9#UniversalClient)
interface. The interfaces exposes all available commands.
- In generalm, dead code elimination should be able to take care of not
generating the machine code for methods that aren't being used. However
in this specific case, dead code elimination either is disabled or gives
up on trying because of exhaustive call stack the client by
`GetRedisClient` is used.
- Help the Go compiler by explicitly specifying which methods we use.
This reduces the binary size by ~400KB (397312 bytes). As Go no longer
generate machine code for commands that aren't being used.
- There's a **CAVEAT** with this, if a developer wants to use a new
method that isn't specified, they will have to know about this
hack (by following the definition of existing Redis methods) and add the
method definition from the Redis library to the `RedisClient` interface.

modules/cache/cache_redis.go

@@ -12,12 +12,11 @@ import (
 	"code.gitea.io/gitea/modules/nosql"
 
 	"code.forgejo.org/go-chi/cache"
-	"github.com/redis/go-redis/v9"
 )
 
 // RedisCacher represents a redis cache adapter implementation.
 type RedisCacher struct {
-	c          redis.UniversalClient
+	c          nosql.RedisClient
 	prefix     string
 	hsetName   string
 	occupyMode bool

modules/nosql/manager.go

@@ -27,8 +27,46 @@ type Manager struct {
 	LevelDBConnections map[string]*levelDBHolder
 }
 
+// RedisClient is a subset of redis.UniversalClient, it exposes less methods
+// to avoid generating machine code for unused methods. New method definitions
+// should be copied from the definitions in the Redis library github.com/redis/go-redis.
+type RedisClient interface {
+	// redis.GenericCmdable
+	Del(ctx context.Context, keys ...string) *redis.IntCmd
+	Exists(ctx context.Context, keys ...string) *redis.IntCmd
+
+	// redis.ListCmdable
+	RPush(ctx context.Context, key string, values ...any) *redis.IntCmd
+	LPop(ctx context.Context, key string) *redis.StringCmd
+	LLen(ctx context.Context, key string) *redis.IntCmd
+
+	// redis.StringCmdable
+	Decr(ctx context.Context, key string) *redis.IntCmd
+	Incr(ctx context.Context, key string) *redis.IntCmd
+	Set(ctx context.Context, key string, value any, expiration time.Duration) *redis.StatusCmd
+	Get(ctx context.Context, key string) *redis.StringCmd
+
+	// redis.HashCmdable
+	HSet(ctx context.Context, key string, values ...any) *redis.IntCmd
+	HDel(ctx context.Context, key string, fields ...string) *redis.IntCmd
+	HKeys(ctx context.Context, key string) *redis.StringSliceCmd
+
+	// redis.SetCmdable
+	SAdd(ctx context.Context, key string, members ...any) *redis.IntCmd
+	SRem(ctx context.Context, key string, members ...any) *redis.IntCmd
+	SIsMember(ctx context.Context, key string, member any) *redis.BoolCmd
+
+	// redis.Cmdable
+	DBSize(ctx context.Context) *redis.IntCmd
+	FlushDB(ctx context.Context) *redis.StatusCmd
+	Ping(ctx context.Context) *redis.StatusCmd
+
+	// redis.UniversalClient
+	Close() error
+}
+
 type redisClientHolder struct {
-	redis.UniversalClient
+	RedisClient
 	name  []string
 	count int64
 }

modules/nosql/manager_redis.go

@@ -39,11 +39,11 @@ func (m *Manager) CloseRedisClient(connection string) error {
 	for _, name := range client.name {
 		delete(m.RedisConnections, name)
 	}
-	return client.UniversalClient.Close()
+	return client.RedisClient.Close()
 }
 
 // GetRedisClient gets a redis client for a particular connection
-func (m *Manager) GetRedisClient(connection string) (client redis.UniversalClient) {
+func (m *Manager) GetRedisClient(connection string) (client RedisClient) {
 	// Because we want associate any goroutines created by this call to the main nosqldb context we need to
 	// wrap this in a goroutine labelled with the nosqldb context
 	done := make(chan struct{})
@@ -67,7 +67,7 @@ func (m *Manager) GetRedisClient(connection string) (client redis.UniversalClien
 	return client
 }
 
-func (m *Manager) getRedisClient(connection string) redis.UniversalClient {
+func (m *Manager) getRedisClient(connection string) RedisClient {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 	client, ok := m.RedisConnections[connection]
@@ -102,24 +102,24 @@ func (m *Manager) getRedisClient(connection string) redis.UniversalClient {
 		opts.TLSConfig = tlsConfig
 		fallthrough
 	case "redis+sentinel":
-		client.UniversalClient = redis.NewFailoverClient(opts.Failover())
+		client.RedisClient = redis.NewFailoverClient(opts.Failover())
 	case "redis+clusters":
 		fallthrough
 	case "rediss+cluster":
 		opts.TLSConfig = tlsConfig
 		fallthrough
 	case "redis+cluster":
-		client.UniversalClient = redis.NewClusterClient(opts.Cluster())
+		client.RedisClient = redis.NewClusterClient(opts.Cluster())
 	case "redis+socket":
 		simpleOpts := opts.Simple()
 		simpleOpts.Network = "unix"
 		simpleOpts.Addr = path.Join(uri.Host, uri.Path)
-		client.UniversalClient = redis.NewClient(simpleOpts)
+		client.RedisClient = redis.NewClient(simpleOpts)
 	case "rediss":
 		opts.TLSConfig = tlsConfig
 		fallthrough
 	case "redis":
-		client.UniversalClient = redis.NewClient(opts.Simple())
+		client.RedisClient = redis.NewClient(opts.Simple())
 	default:
 		return nil
 	}

modules/queue/base_redis.go

@@ -16,7 +16,7 @@ import (
 )
 
 type baseRedis struct {
-	client   redis.UniversalClient
+	client   nosql.RedisClient
 	isUnique bool
 	cfg      *BaseConfig
 	prefix   string
@@ -26,7 +26,7 @@ type baseRedis struct {
 
 var _ baseQueue = (*baseRedis)(nil)
 
-func newBaseRedisGeneric(cfg *BaseConfig, unique bool, client redis.UniversalClient) (baseQueue, error) {
+func newBaseRedisGeneric(cfg *BaseConfig, unique bool, client nosql.RedisClient) (baseQueue, error) {
 	if client == nil {
 		client = nosql.GetManager().GetRedisClient(cfg.ConnStr)
 	}

modules/session/redis.go

@@ -26,12 +26,11 @@ import (
 	"code.gitea.io/gitea/modules/nosql"
 
 	"code.forgejo.org/go-chi/session"
-	"github.com/redis/go-redis/v9"
 )
 
 // RedisStore represents a redis session store implementation.
 type RedisStore struct {
-	c           redis.UniversalClient
+	c           nosql.RedisClient
 	prefix, sid string
 	duration    time.Duration
 	lock        sync.RWMutex
@@ -39,7 +38,7 @@ type RedisStore struct {
 }
 
 // NewRedisStore creates and returns a redis session store.
-func NewRedisStore(c redis.UniversalClient, prefix, sid string, dur time.Duration, kv map[any]any) *RedisStore {
+func NewRedisStore(c nosql.RedisClient, prefix, sid string, dur time.Duration, kv map[any]any) *RedisStore {
 	return &RedisStore{
 		c:        c,
 		prefix:   prefix,
@@ -106,7 +105,7 @@ func (s *RedisStore) Flush() error {
 
 // RedisProvider represents a redis session provider implementation.
 type RedisProvider struct {
-	c        redis.UniversalClient
+	c        nosql.RedisClient
 	duration time.Duration
 	prefix   string
 }