Updating grpc handler to gracefully close backend connections

This should address part 1 of #807 and #912

update grpc docs

config/config.go

@@ -93,6 +93,7 @@ type Proxy struct {
 	AuthSchemes           map[string]AuthScheme
 	GRPCMaxRxMsgSize      int
 	GRPCMaxTxMsgSize      int
+	GRPCGShutdownTimeout  time.Duration
 }
 
 type STSHeader struct {

config/default.go

@@ -42,18 +42,19 @@ var defaultConfig = &Config{
 		},
 	},
 	Proxy: Proxy{
-		MaxConn:             10000,
-		Strategy:            "rnd",
-		Matcher:             "prefix",
-		NoRouteStatus:       404,
-		DialTimeout:         30 * time.Second,
-		FlushInterval:       time.Second,
-		GlobalFlushInterval: 0,
-		LocalIP:             LocalIPString(),
-		AuthSchemes:         map[string]AuthScheme{},
-		IdleConnTimeout:     15 * time.Second,
-		GRPCMaxRxMsgSize:    4 * 1024 * 1024, // 4M
-		GRPCMaxTxMsgSize:    4 * 1024 * 1024, // 4M
+		MaxConn:              10000,
+		Strategy:             "rnd",
+		Matcher:              "prefix",
+		NoRouteStatus:        404,
+		DialTimeout:          30 * time.Second,
+		FlushInterval:        time.Second,
+		GlobalFlushInterval:  0,
+		LocalIP:              LocalIPString(),
+		AuthSchemes:          map[string]AuthScheme{},
+		IdleConnTimeout:      15 * time.Second,
+		GRPCMaxRxMsgSize:     4 * 1024 * 1024, // 4M
+		GRPCMaxTxMsgSize:     4 * 1024 * 1024, // 4M
+		GRPCGShutdownTimeout: time.Second * 2,
 	},
 	Registry: Registry{
 		Backend: "consul",

config/kvslice.go

@@ -8,15 +8,15 @@ import (
 
 // parseKVSlice parses a configuration string in the form
 //
-//	key=val;key=val,key=val;key=val
+//   key=val;key=val,key=val;key=val
 //
 // into a list of string maps. maps are separated by comma and key/value
 // pairs within a map are separated by semicolons. The first key/value
 // pair of a map can omit the key and its value will be stored under the
 // empty key. This allows support of legacy configuration formats which
 // are
 //
-//	val;opt1=val1;opt2=val2;...
+//   val;opt1=val1;opt2=val2;...
 func parseKVSlice(in string) ([]map[string]string, error) {
 	var keyOrFirstVal string
 	maps := []map[string]string{}

config/load.go

@@ -153,6 +153,7 @@ func load(cmdline, environ, envprefix []string, props *properties.Properties) (c
 	f.BoolVar(&cfg.Proxy.STSHeader.Preload, "proxy.header.sts.preload", defaultConfig.Proxy.STSHeader.Preload, "direct HSTS to pass the preload directive")
 	f.IntVar(&cfg.Proxy.GRPCMaxRxMsgSize, "proxy.grpcmaxrxmsgsize", defaultConfig.Proxy.GRPCMaxRxMsgSize, "max grpc receive message size (in bytes)")
 	f.IntVar(&cfg.Proxy.GRPCMaxTxMsgSize, "proxy.grpcmaxtxmsgsize", defaultConfig.Proxy.GRPCMaxTxMsgSize, "max grpc transmit message size (in bytes)")
+	f.DurationVar(&cfg.Proxy.GRPCGShutdownTimeout, "proxy.grpcshutdowntimeout", defaultConfig.Proxy.GRPCGShutdownTimeout, "amount of time to wait for graceful shutdown of grpc backend")
 	f.StringVar(&gzipContentTypesValue, "proxy.gzip.contenttype", defaultValues.GZIPContentTypesValue, "regexp of content types to compress")
 	f.StringVar(&listenerValue, "proxy.addr", defaultValues.ListenerValue, "listener config")
 	f.StringVar(&certSourcesValue, "proxy.cs", defaultValues.CertSourcesValue, "certificate sources")

demo/server/server.go

@@ -4,33 +4,34 @@
 //
 // During startup the server performs the following steps:
 //
-//   - Add a handler for each prefix which provides a unique
-//     response for that instance and endpoint
-//   - Add a `/health` handler for the consul health check
-//   - Register the service in consul with the listen address,
-//     a health check under the given name and with one `urlprefix-`
-//     tag per prefix
-//   - Install a signal handler to deregister the service on exit
+// * Add a handler for each prefix which provides a unique
+//   response for that instance and endpoint
+// * Add a `/health` handler for the consul health check
+// * Register the service in consul with the listen address,
+//   a health check under the given name and with one `urlprefix-`
+//   tag per prefix
+// * Install a signal handler to deregister the service on exit
 //
 // If the protocol is set to "ws" the registered endpoints function
 // as websocket echo servers.
 //
 // Example:
 //
-//	# http server
-//	./server -addr 127.0.0.1:5000 -name svc-a -prefix /foo -prefix /bar
-//	./server -addr 127.0.0.1:5001 -name svc-b -prefix /baz -prefix /bar
-//	./server -addr 127.0.0.1:5002 -name svc-c -prefix "/gogl redirect=301,https://www.google.de/"
+//   # http server
+//   ./server -addr 127.0.0.1:5000 -name svc-a -prefix /foo -prefix /bar
+//   ./server -addr 127.0.0.1:5001 -name svc-b -prefix /baz -prefix /bar
+//   ./server -addr 127.0.0.1:5002 -name svc-c -prefix "/gogl redirect=301,https://www.google.de/"
 //
-//	# https server
-//	./server -addr 127.0.0.1:5000 -name svc-a -proto https -certFile ... -keyFile ... -prefix /foo
-//	./server -addr 127.0.0.1:5000 -name svc-a -proto https -certFile ... -keyFile ... -prefix "/foo tlsskipverify=true"
+//   # https server
+//   ./server -addr 127.0.0.1:5000 -name svc-a -proto https -certFile ... -keyFile ... -prefix /foo
+//   ./server -addr 127.0.0.1:5000 -name svc-a -proto https -certFile ... -keyFile ... -prefix "/foo tlsskipverify=true"
 //
-//	# websocket server
-//	./server -addr 127.0.0.1:6000 -name ws-a -proto ws -prefix /echo1 -prefix /echo2
+//   # websocket server
+//   ./server -addr 127.0.0.1:6000 -name ws-a -proto ws -prefix /echo1 -prefix /echo2
+//
+//   # tcp server
+//   ./server -addr 127.0.0.1:7000 -name tcp-a -proto tcp -prefix :1234
 //
-//	# tcp server
-//	./server -addr 127.0.0.1:7000 -name tcp-a -proto tcp -prefix :1234
 package main
 
 import (

docs/content/ref/proxy.grpcmaxrxmsgsize.md

@@ -0,0 +1,10 @@
+---
+title: "proxy.grpcmaxrxmsgsize"
+---
+
+`proxy.grpcmaxrxmsgsize` configures the grpc max receive message size in bytes.  The default
+value is
+
+    proxy.grpcmaxrxmsgsize = 4194304
+
+which is 4MB

docs/content/ref/proxy.grpcmaxtxmsgsize.md

@@ -0,0 +1,10 @@
+---
+title: "proxy.grpcmaxtxmsgsize"
+---
+
+`proxy.grpcmaxtxmsgsize` configures the grpc max transmit message size in bytes.  The default
+value is
+
+    proxy.grpcmaxtxmsgsize = 4194304
+
+which is 4MB

docs/content/ref/proxy.grpcshutdowntimeout.md

@@ -0,0 +1,9 @@
+---
+title: "proxy.grpcshutdowntimeout"
+---
+
+`proxy.grpcshutdowntimeout` configures the amount of time fabio will wait to attempt
+to close the connection while waiting for grpc traffic to finish to a backend that's been
+deregistered.  The default value is
+
+    proxy.grpcshutdowntimeout = 2s

fabio.properties

@@ -561,6 +561,12 @@
 # The default is
 # proxy.grpcmaxtxmsgsize = 4194304
 #
+#
+# proxy.grpcshutdowntimeout configures the amount of time fabio will wait to attempt
+# to close the connection while waiting for grpc traffic to finish to a backend that's been
+# deregistered.  Default value is
+# proxy.grpcshutdowntimeout = 2s
+# setting to 0s disables the wait.
 
 # log.access.format configures the format of the access log.
 #

logger/logger.go

@@ -5,37 +5,38 @@
 // takes place. Text between two fields is printed verbatim. See the common
 // log file formats for an example.
 //
-//	$header.<name>           - request http header (name: [a-zA-Z0-9-]+)
-//	$remote_addr             - host:port of remote client
-//	$remote_host             - host of remote client
-//	$remote_port             - port of remote client
-//	$request                 - request <method> <uri> <proto>
-//	$request_args            - request query parameters
-//	$request_host            - request host header (aka server name)
-//	$request_method          - request method
-//	$request_scheme          - request scheme
-//	$request_uri             - request URI
-//	$request_url             - request URL
-//	$request_proto           - request protocol
-//	$response_body_size      - response body size in bytes
-//	$response_status         - response status code
-//	$response_time_ms        - response time in S.sss format
-//	$response_time_us        - response time in S.ssssss format
-//	$response_time_ns        - response time in S.sssssssss format
-//	$time_rfc3339            - log timestamp in YYYY-MM-DDTHH:MM:SSZ format
-//	$time_rfc3339_ms         - log timestamp in YYYY-MM-DDTHH:MM:SS.sssZ format
-//	$time_rfc3339_us         - log timestamp in YYYY-MM-DDTHH:MM:SS.ssssssZ format
-//	$time_rfc3339_ns         - log timestamp in YYYY-MM-DDTHH:MM:SS.sssssssssZ format
-//	$time_unix_ms            - log timestamp in unix epoch ms
-//	$time_unix_us            - log timestamp in unix epoch us
-//	$time_unix_ns            - log timestamp in unix epoch ns
-//	$time_common             - log timestamp in DD/MMM/YYYY:HH:MM:SS -ZZZZ
-//	$upstream_addr           - host:port of upstream server
-//	$upstream_host           - host of upstream server
-//	$upstream_port           - port of upstream server
-//	$upstream_request_scheme - upstream request scheme
-//	$upstream_request_uri    - upstream request URI
-//	$upstream_request_url    - upstream request URL
+//   $header.<name>           - request http header (name: [a-zA-Z0-9-]+)
+//   $remote_addr             - host:port of remote client
+//   $remote_host             - host of remote client
+//   $remote_port             - port of remote client
+//   $request                 - request <method> <uri> <proto>
+//   $request_args            - request query parameters
+//   $request_host            - request host header (aka server name)
+//   $request_method          - request method
+//   $request_scheme          - request scheme
+//   $request_uri             - request URI
+//   $request_url             - request URL
+//   $request_proto           - request protocol
+//   $response_body_size      - response body size in bytes
+//   $response_status         - response status code
+//   $response_time_ms        - response time in S.sss format
+//   $response_time_us        - response time in S.ssssss format
+//   $response_time_ns        - response time in S.sssssssss format
+//   $time_rfc3339            - log timestamp in YYYY-MM-DDTHH:MM:SSZ format
+//   $time_rfc3339_ms         - log timestamp in YYYY-MM-DDTHH:MM:SS.sssZ format
+//   $time_rfc3339_us         - log timestamp in YYYY-MM-DDTHH:MM:SS.ssssssZ format
+//   $time_rfc3339_ns         - log timestamp in YYYY-MM-DDTHH:MM:SS.sssssssssZ format
+//   $time_unix_ms            - log timestamp in unix epoch ms
+//   $time_unix_us            - log timestamp in unix epoch us
+//   $time_unix_ns            - log timestamp in unix epoch ns
+//   $time_common             - log timestamp in DD/MMM/YYYY:HH:MM:SS -ZZZZ
+//   $upstream_addr           - host:port of upstream server
+//   $upstream_host           - host of upstream server
+//   $upstream_port           - port of upstream server
+//   $upstream_request_scheme - upstream request scheme
+//   $upstream_request_uri    - upstream request URI
+//   $upstream_request_url    - upstream request URL
+//
 package logger
 
 import (

proxy/grpc_handler.go

@@ -299,14 +299,21 @@ func (p *grpcConnectionPool) cleanup() {
 		p.lock.Lock()
 		table := route.GetTable()
 		for tKey, cs := range p.connections {
-			if cs.GetState() == connectivity.Shutdown {
+			state := cs.GetState()
+			if state == connectivity.Shutdown {
 				delete(p.connections, tKey)
 				continue
 			}
 
 			if !hasTarget(tKey, table) {
 				log.Println("[DEBUG] grpc: cleaning up connection to", tKey)
-				cs.Close()
+				go func(cs *grpc.ClientConn, state connectivity.State) {
+					ctx, cancel := context.WithTimeout(context.Background(), p.cfg.Proxy.GRPCGShutdownTimeout)
+					defer cancel()
+					// wait for state to change, or timeout, before closing, in case it's still handling traffic.
+					cs.WaitForStateChange(ctx, state)
+					cs.Close()
+				}(cs, state)
 				delete(p.connections, tKey)
 			}
 		}