feature: read timeout filter and write timeout filter (zalando#2271)

* feature: readTimeout filter and writeTimeout filters
docs: add readTimeout and writeTimeout
docs: move backendTimeout to Timeouts section

Signed-off-by: Sandor Szücs <[email protected]>

* drop implicit integer to ms value

Signed-off-by: Sandor Szücs <[email protected]>

---------

Signed-off-by: Sandor Szücs <[email protected]>

Author: szuecs

docs/reference/filters.md

@@ -536,23 +536,6 @@ Examples:
 
 You may use https://github.com/AlexanderYastrebov/unrepeat to decompose binary file into prefix, repeating content and suffix.
 
-### backendTimeout
-
-Configure backend timeout. Skipper responds with `504 Gateway Timeout` status if obtaining a connection,
-sending the request, and reading the backend response headers and body takes longer than the configured timeout.
-However, if response streaming has already started it will be terminated, i.e. client will receive backend response
-status and truncated response body.
-
-Parameters:
-
-* timeout [(duration string)](https://godoc.org/time#ParseDuration)
-
-Example:
-
-```
-* -> backendTimeout("10ms") -> "https://www.example.org";
-```
-
 ### latency
 
 Enable adding artificial latency
@@ -705,6 +688,64 @@ Example:
 * -> logHeader("request", "response") -> "https://www.example.org";
 ```
 
+## Timeout
+
+### backendTimeout
+
+Configure backend timeout. Skipper responds with `504 Gateway Timeout` status if obtaining a connection,
+sending the request, and reading the backend response headers and body takes longer than the configured timeout.
+However, if response streaming has already started it will be terminated, i.e. client will receive backend response
+status and truncated response body.
+
+Parameters:
+
+* timeout [(duration string)](https://godoc.org/time#ParseDuration)
+
+Example:
+
+```
+* -> backendTimeout("10ms") -> "https://www.example.org";
+```
+
+### readTimeout
+
+Configure read timeout will set a read deadline on the server socket
+connected to the client connecting to the proxy. Skipper will log 499
+client timeout with context canceled. We are not able to differentiate
+between client hang up and read timeout.
+
+Parameters:
+
+* timeout [(duration string)](https://godoc.org/time#ParseDuration)
+
+Example:
+
+```
+* -> readTimeout("10ms") -> "https://www.example.org";
+```
+
+### writeTimeout
+
+Configure write timeout will set a write deadline on the server socket
+connected to the client connecting to the proxy. Skipper will show
+access logs as if the response was served as expected, but the client can
+show an error. You can observe an increase in streaming errors via
+metrics or a in opentracing proxy span you can see Tag
+`streamBody.byte` with value `streamBody error` or in debug logs
+something like
+`error while copying the response stream: write tcp 127.0.0.1:9090->127.0.0.1:38574: i/o timeout`.
+
+Parameters:
+
+* timeout [(duration string)](https://godoc.org/time#ParseDuration)
+
+Example:
+
+```
+* -> writeTimeout("10ms") -> "https://www.example.org";
+```
+
+
 ## Shadow Traffic
 ### tee
 

filters/builtin/builtin.go

@@ -156,6 +156,8 @@ func Filters() []filters.Spec {
 		NewHeaderToQuery(),
 		NewQueryToHeader(),
 		NewBackendTimeout(),
+		NewReadTimeout(),
+		NewWriteTimeout(),
 		NewSetDynamicBackendHostFromHeader(),
 		NewSetDynamicBackendSchemeFromHeader(),
 		NewSetDynamicBackendUrlFromHeader(),

filters/builtin/timeout.go

@@ -6,22 +6,56 @@ import (
 	"github.com/zalando/skipper/filters"
 )
 
+type timeoutType int
+
+const (
+	backendTimeout timeoutType = iota + 1
+	readTimeout
+	writeTimeout
+)
+
 type timeout struct {
+	typ     timeoutType
 	timeout time.Duration
 }
 
 func NewBackendTimeout() filters.Spec {
-	return &timeout{}
+	return &timeout{
+		typ: backendTimeout,
+	}
 }
 
-func (*timeout) Name() string { return filters.BackendTimeoutName }
+func NewReadTimeout() filters.Spec {
+	return &timeout{
+		typ: readTimeout,
+	}
+}
 
-func (*timeout) CreateFilter(args []interface{}) (filters.Filter, error) {
+func NewWriteTimeout() filters.Spec {
+	return &timeout{
+		typ: writeTimeout,
+	}
+}
+
+func (t *timeout) Name() string {
+	switch t.typ {
+	case backendTimeout:
+		return filters.BackendTimeoutName
+	case readTimeout:
+		return filters.ReadTimeoutName
+	case writeTimeout:
+		return filters.WriteTimeoutName
+	}
+	return "unknownFilter"
+}
+
+func (t *timeout) CreateFilter(args []interface{}) (filters.Filter, error) {
 	if len(args) != 1 {
 		return nil, filters.ErrInvalidFilterParameters
 	}
 
 	var tf timeout
+	tf.typ = t.typ
 	switch v := args[0].(type) {
 	case string:
 		d, err := time.ParseDuration(v)
@@ -37,9 +71,26 @@ func (*timeout) CreateFilter(args []interface{}) (filters.Filter, error) {
 	return &tf, nil
 }
 
+// Request allows overwrite of timeout settings.
+//
+// Type backend timeout sets the timeout for the backend roundtrip.
+//
+// Type read timeout sets the timeout to read the request including the body.
+// It uses http.ResponseController to SetReadDeadline().
+//
+// Type write timeout allows to set a timeout for writing the response.
+// It uses http.ResponseController to SetWriteDeadline().
+//
+// All these timeouts are set at specific points in proxy.Proxy.
 func (t *timeout) Request(ctx filters.FilterContext) {
-	// allows overwrite
-	ctx.StateBag()[filters.BackendTimeout] = t.timeout
+	switch t.typ {
+	case backendTimeout:
+		ctx.StateBag()[filters.BackendTimeout] = t.timeout
+	case readTimeout:
+		ctx.StateBag()[filters.ReadTimeout] = t.timeout
+	case writeTimeout:
+		ctx.StateBag()[filters.WriteTimeout] = t.timeout
+	}
 }
 
-func (t *timeout) Response(filters.FilterContext) {}
+func (*timeout) Response(filters.FilterContext) {}