Set self-adjusting deadline for connection writing (#16068)

* Set self-adjusting deadline for connection writing

In #16055 it appears that the simple 5s deadline doesn't work for large
file writes. Now we can't - or at least shouldn't just set no deadline
as go will happily let these connections block indefinitely. However,
what seems reasonable is to set some minimum rate we expect for writing.

This PR suggests the following algorithm:

* Every write has a minimum timeout of 5s (adjustable at compile time.)
* If there has been a previous write - then consider its previous
deadline, add half of the minimum timeout + 2s per kb about to written.
* If that new deadline is after the minimum timeout use that.

Fix #16055

* Linearly increase timeout

* Make PerWriteTimeout, PerWritePerKbTimeouts configurable

Signed-off-by: Andrew Thornton <art27@cantab.net>

Co-authored-by: 6543 <6543@obermui.de>

Author: zeripath

custom/conf/app.example.ini

@@ -51,6 +51,12 @@ RUN_MODE = ; prod
 ;REDIRECT_OTHER_PORT = false
 ;PORT_TO_REDIRECT = 80
 ;;
+;; Timeout for any write to the connection. (Set to 0 to disable all timeouts.)
+;PER_WRITE_TIMEOUT = 30s
+;;
+;; Timeout per Kb written to connections.
+;PER_WRITE_PER_KB_TIMEOUT = 30s
+;;
 ;; Permission for unix socket
 ;UNIX_SOCKET_PERMISSION = 666
 ;;
@@ -144,6 +150,14 @@ RUN_MODE = ; prod
 ;; Enable exposure of SSH clone URL to anonymous visitors, default is false
 ;SSH_EXPOSE_ANONYMOUS = false
 ;;
+;; Timeout for any write to ssh connections. (Set to 0 to disable all timeouts.)
+;; Will default to the PER_WRITE_TIMEOUT.
+;SSH_PER_WRITE_TIMEOUT = 30s
+;;
+;; Timeout per Kb written to ssh connections.
+;; Will default to the PER_WRITE_PER_KB_TIMEOUT.
+;SSH_PER_WRITE_PER_KB_TIMEOUT = 30s
+;;
 ;; Indicate whether to check minimum key size with corresponding type
 ;MINIMUM_KEY_SIZE_CHECK = false
 ;;
@@ -1145,8 +1159,8 @@ PATH =
 ;;
 ;; When ISSUE_INDEXER_QUEUE_TYPE is levelqueue, this will be the path where the queue will be saved.
 ;; This can be overridden by `ISSUE_INDEXER_QUEUE_CONN_STR`.
-;; default is queues/common
-;ISSUE_INDEXER_QUEUE_DIR = queues/common
+;; default is queues/common
+;ISSUE_INDEXER_QUEUE_DIR = queues/common
 ;;
 ;; When `ISSUE_INDEXER_QUEUE_TYPE` is `redis`, this will store the redis connection string.
 ;; When `ISSUE_INDEXER_QUEUE_TYPE` is `levelqueue`, this is a directory or additional options of
@@ -1201,7 +1215,7 @@ PATH =
 ;; default to persistable-channel
 ;TYPE = persistable-channel
 ;;
-;; data-dir for storing persistable queues and level queues, individual queues will default to `queues/common` meaning the queue is shared.
+;; data-dir for storing persistable queues and level queues, individual queues will default to `queues/common` meaning the queue is shared.
 ;DATADIR = queues/
 ;;
 ;; Default queue length before a channel queue will block

docs/content/doc/advanced/config-cheat-sheet.en-us.md

@@ -251,6 +251,9 @@ The following configuration set `Content-Type: application/vnd.android.package-a
    most cases you do not need to change the default value. Alter it only if
    your SSH server node is not the same as HTTP node. Do not set this variable
    if `PROTOCOL` is set to `unix`.
+- `PER_WRITE_TIMEOUT`: **30s**: Timeout for any write to the connection. (Set to 0 to
+   disable all timeouts.)
+- `PER_WRITE_PER_KB_TIMEOUT`: **10s**: Timeout per Kb written to connections.
 
 - `DISABLE_SSH`: **false**: Disable SSH feature when it's not available.
 - `START_SSH_SERVER`: **false**: When enabled, use the built-in SSH server.
@@ -274,6 +277,9 @@ The following configuration set `Content-Type: application/vnd.android.package-a
 - `SSH_KEY_TEST_PATH`: **/tmp**: Directory to create temporary files in when testing public keys using ssh-keygen, default is the system temporary directory.
 - `SSH_KEYGEN_PATH`: **ssh-keygen**: Path to ssh-keygen, default is 'ssh-keygen' which means the shell is responsible for finding out which one to call.
 - `SSH_EXPOSE_ANONYMOUS`: **false**: Enable exposure of SSH clone URL to anonymous visitors, default is false.
+- `SSH_PER_WRITE_TIMEOUT`: **30s**: Timeout for any write to the SSH connections. (Set to
+  0 to disable all timeouts.)
+- `SSH_PER_WRITE_PER_KB_TIMEOUT`: **10s**: Timeout per Kb written to SSH connections.
 - `MINIMUM_KEY_SIZE_CHECK`: **true**: Indicate whether to check minimum key size with corresponding type.
 
 - `OFFLINE_MODE`: **false**: Disables use of CDN for static files and Gravatar for profile pictures.
@@ -350,7 +356,7 @@ relation to port exhaustion.
 - `ISSUE_INDEXER_PATH`: **indexers/issues.bleve**: Index file used for issue search; available when ISSUE_INDEXER_TYPE is bleve and elasticsearch.
 - The next 4 configuration values are deprecated and should be set in `queue.issue_indexer` however are kept for backwards compatibility:
 - `ISSUE_INDEXER_QUEUE_TYPE`: **levelqueue**: Issue indexer queue, currently supports:`channel`, `levelqueue`, `redis`.
-- `ISSUE_INDEXER_QUEUE_DIR`: **queues/common**: When `ISSUE_INDEXER_QUEUE_TYPE` is `levelqueue`, this will be the path where the queue will be saved. (Previously this was `indexers/issues.queue`.)
+- `ISSUE_INDEXER_QUEUE_DIR`: **queues/common**: When `ISSUE_INDEXER_QUEUE_TYPE` is `levelqueue`, this will be the path where the queue will be saved. (Previously this was `indexers/issues.queue`.)
 - `ISSUE_INDEXER_QUEUE_CONN_STR`: **addrs=127.0.0.1:6379 db=0**: When `ISSUE_INDEXER_QUEUE_TYPE` is `redis`, this will store the redis connection string. When `ISSUE_INDEXER_QUEUE_TYPE` is `levelqueue`, this is a directory or additional options of the form `leveldb://path/to/db?option=value&....`, and overrides `ISSUE_INDEXER_QUEUE_DIR`.
 - `ISSUE_INDEXER_QUEUE_BATCH_NUMBER`: **20**: Batch queue number.
 
@@ -370,7 +376,7 @@ relation to port exhaustion.
 ## Queue (`queue` and `queue.*`)
 
 - `TYPE`: **persistable-channel**: General queue type, currently support: `persistable-channel` (uses a LevelDB internally), `channel`, `level`, `redis`, `dummy`
-- `DATADIR`: **queues/**: Base DataDir for storing persistent and level queues. `DATADIR` for individual queues can be set in `queue.name` sections but will default to `DATADIR/`**`common`**. (Previously each queue would default to `DATADIR/`**`name`**.)
+- `DATADIR`: **queues/**: Base DataDir for storing persistent and level queues. `DATADIR` for individual queues can be set in `queue.name` sections but will default to `DATADIR/`**`common`**. (Previously each queue would default to `DATADIR/`**`name`**.)
 - `LENGTH`: **20**: Maximal queue size before channel queues block
 - `BATCH_LENGTH`: **20**: Batch data before passing to the handler
 - `CONN_STR`: **redis://127.0.0.1:6379/0**: Connection string for the redis queue type. Options can be set using query params. Similarly LevelDB options can also be set using: **leveldb://relative/path?option=value** or **leveldb:///absolute/path?option=value**, and will override `DATADIR`

modules/graceful/server.go

@@ -17,6 +17,7 @@ import (
 	"time"
 
 	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/setting"
 )
 
 var (
@@ -26,11 +27,12 @@ var (
 	DefaultWriteTimeOut time.Duration
 	// DefaultMaxHeaderBytes default max header bytes
 	DefaultMaxHeaderBytes int
+	// PerWriteWriteTimeout timeout for writes
+	PerWriteWriteTimeout = 30 * time.Second
+	// PerWriteWriteTimeoutKbTime is a timeout taking account of how much there is to be written
+	PerWriteWriteTimeoutKbTime = 10 * time.Second
 )
 
-// PerWriteWriteTimeout timeout for writes
-const PerWriteWriteTimeout = 5 * time.Second
-
 func init() {
 	DefaultMaxHeaderBytes = 0 // use http.DefaultMaxHeaderBytes - which currently is 1 << 20 (1MB)
 }
@@ -40,14 +42,16 @@ type ServeFunction = func(net.Listener) error
 
 // Server represents our graceful server
 type Server struct {
-	network     string
-	address     string
-	listener    net.Listener
-	wg          sync.WaitGroup
-	state       state
-	lock        *sync.RWMutex
-	BeforeBegin func(network, address string)
-	OnShutdown  func()
+	network              string
+	address              string
+	listener             net.Listener
+	wg                   sync.WaitGroup
+	state                state
+	lock                 *sync.RWMutex
+	BeforeBegin          func(network, address string)
+	OnShutdown           func()
+	PerWriteTimeout      time.Duration
+	PerWritePerKbTimeout time.Duration
 }
 
 // NewServer creates a server on network at provided address
@@ -58,11 +62,13 @@ func NewServer(network, address, name string) *Server {
 		log.Info("Starting new %s server: %s:%s on PID: %d", name, network, address, os.Getpid())
 	}
 	srv := &Server{
-		wg:      sync.WaitGroup{},
-		state:   stateInit,
-		lock:    &sync.RWMutex{},
-		network: network,
-		address: address,
+		wg:                   sync.WaitGroup{},
+		state:                stateInit,
+		lock:                 &sync.RWMutex{},
+		network:              network,
+		address:              address,
+		PerWriteTimeout:      setting.PerWriteTimeout,
+		PerWritePerKbTimeout: setting.PerWritePerKbTimeout,
 	}
 
 	srv.BeforeBegin = func(network, addr string) {
@@ -224,9 +230,11 @@ func (wl *wrappedListener) Accept() (net.Conn, error) {
 	closed := int32(0)
 
 	c = wrappedConn{
-		Conn:   c,
-		server: wl.server,
-		closed: &closed,
+		Conn:                 c,
+		server:               wl.server,
+		closed:               &closed,
+		perWriteTimeout:      wl.server.PerWriteTimeout,
+		perWritePerKbTimeout: wl.server.PerWritePerKbTimeout,
 	}
 
 	wl.server.wg.Add(1)
@@ -249,13 +257,23 @@ func (wl *wrappedListener) File() (*os.File, error) {
 
 type wrappedConn struct {
 	net.Conn
-	server *Server
-	closed *int32
+	server               *Server
+	closed               *int32
+	deadline             time.Time
+	perWriteTimeout      time.Duration
+	perWritePerKbTimeout time.Duration
 }
 
 func (w wrappedConn) Write(p []byte) (n int, err error) {
-	if PerWriteWriteTimeout > 0 {
-		_ = w.Conn.SetWriteDeadline(time.Now().Add(PerWriteWriteTimeout))
+	if w.perWriteTimeout > 0 {
+		minTimeout := time.Duration(len(p)/1024) * w.perWritePerKbTimeout
+		minDeadline := time.Now().Add(minTimeout).Add(w.perWriteTimeout)
+
+		w.deadline = w.deadline.Add(minTimeout)
+		if minDeadline.After(w.deadline) {
+			w.deadline = minDeadline
+		}
+		_ = w.Conn.SetWriteDeadline(w.deadline)
 	}
 	return w.Conn.Write(p)
 }

modules/setting/setting.go

@@ -117,6 +117,8 @@ var (
 	GracefulRestartable  bool
 	GracefulHammerTime   time.Duration
 	StartupTimeout       time.Duration
+	PerWriteTimeout      = 30 * time.Second
+	PerWritePerKbTimeout = 10 * time.Second
 	StaticURLPrefix      string
 	AbsoluteAssetURL     string
 
@@ -147,18 +149,22 @@ var (
 		TrustedUserCAKeys              []string          `ini:"SSH_TRUSTED_USER_CA_KEYS"`
 		TrustedUserCAKeysFile          string            `ini:"SSH_TRUSTED_USER_CA_KEYS_FILENAME"`
 		TrustedUserCAKeysParsed        []gossh.PublicKey `ini:"-"`
+		PerWriteTimeout                time.Duration     `ini:"SSH_PER_WRITE_TIMEOUT"`
+		PerWritePerKbTimeout           time.Duration     `ini:"SSH_PER_WRITE_PER_KB_TIMEOUT"`
 	}{
-		Disabled:            false,
-		StartBuiltinServer:  false,
-		Domain:              "",
-		Port:                22,
-		ServerCiphers:       []string{"aes128-ctr", "aes192-ctr", "aes256-ctr", "aes128-gcm@openssh.com", "arcfour256", "arcfour128"},
-		ServerKeyExchanges:  []string{"diffie-hellman-group1-sha1", "diffie-hellman-group14-sha1", "ecdh-sha2-nistp256", "ecdh-sha2-nistp384", "ecdh-sha2-nistp521", "curve25519-sha256@libssh.org"},
-		ServerMACs:          []string{"hmac-sha2-256-etm@openssh.com", "hmac-sha2-256", "hmac-sha1", "hmac-sha1-96"},
-		KeygenPath:          "ssh-keygen",
-		MinimumKeySizeCheck: true,
-		MinimumKeySizes:     map[string]int{"ed25519": 256, "ed25519-sk": 256, "ecdsa": 256, "ecdsa-sk": 256, "rsa": 2048},
-		ServerHostKeys:      []string{"ssh/gitea.rsa", "ssh/gogs.rsa"},
+		Disabled:             false,
+		StartBuiltinServer:   false,
+		Domain:               "",
+		Port:                 22,
+		ServerCiphers:        []string{"aes128-ctr", "aes192-ctr", "aes256-ctr", "aes128-gcm@openssh.com", "arcfour256", "arcfour128"},
+		ServerKeyExchanges:   []string{"diffie-hellman-group1-sha1", "diffie-hellman-group14-sha1", "ecdh-sha2-nistp256", "ecdh-sha2-nistp384", "ecdh-sha2-nistp521", "curve25519-sha256@libssh.org"},
+		ServerMACs:           []string{"hmac-sha2-256-etm@openssh.com", "hmac-sha2-256", "hmac-sha1", "hmac-sha1-96"},
+		KeygenPath:           "ssh-keygen",
+		MinimumKeySizeCheck:  true,
+		MinimumKeySizes:      map[string]int{"ed25519": 256, "ed25519-sk": 256, "ecdsa": 256, "ecdsa-sk": 256, "rsa": 2048},
+		ServerHostKeys:       []string{"ssh/gitea.rsa", "ssh/gogs.rsa"},
+		PerWriteTimeout:      PerWriteTimeout,
+		PerWritePerKbTimeout: PerWritePerKbTimeout,
 	}
 
 	// Security settings
@@ -612,6 +618,8 @@ func NewContext() {
 	GracefulRestartable = sec.Key("ALLOW_GRACEFUL_RESTARTS").MustBool(true)
 	GracefulHammerTime = sec.Key("GRACEFUL_HAMMER_TIME").MustDuration(60 * time.Second)
 	StartupTimeout = sec.Key("STARTUP_TIMEOUT").MustDuration(0 * time.Second)
+	PerWriteTimeout = sec.Key("PER_WRITE_TIMEOUT").MustDuration(PerWriteTimeout)
+	PerWritePerKbTimeout = sec.Key("PER_WRITE_PER_KB_TIMEOUT").MustDuration(PerWritePerKbTimeout)
 
 	defaultAppURL := string(Protocol) + "://" + Domain
 	if (Protocol == HTTP && HTTPPort != "80") || (Protocol == HTTPS && HTTPPort != "443") {
@@ -777,6 +785,8 @@ func NewContext() {
 	}
 
 	SSH.ExposeAnonymous = sec.Key("SSH_EXPOSE_ANONYMOUS").MustBool(false)
+	SSH.PerWriteTimeout = sec.Key("SSH_PER_WRITE_TIMEOUT").MustDuration(PerWriteTimeout)
+	SSH.PerWritePerKbTimeout = sec.Key("SSH_PER_WRITE_PER_KB_TIMEOUT").MustDuration(PerWritePerKbTimeout)
 
 	if err = Cfg.Section("oauth2").MapTo(&OAuth2); err != nil {
 		log.Fatal("Failed to OAuth2 settings: %v", err)

modules/ssh/ssh_graceful.go

@@ -7,12 +7,15 @@ package ssh
 import (
 	"code.gitea.io/gitea/modules/graceful"
 	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/setting"
 
 	"github.com/gliderlabs/ssh"
 )
 
 func listen(server *ssh.Server) {
 	gracefulServer := graceful.NewServer("tcp", server.Addr, "SSH")
+	gracefulServer.PerWriteTimeout = setting.SSH.PerWriteTimeout
+	gracefulServer.PerWritePerKbTimeout = setting.SSH.PerWritePerKbTimeout
 
 	err := gracefulServer.ListenAndServe(server.Serve)
 	if err != nil {