Add Go pprof support to the orderer

Fixes FAB-813. The profiling service is disabled by default, and defaults to
using the 0.0.0.0:6060 interface if enabled.

Change-Id: Ia8abaaacf1a8524444af6c0697c622386c4939d9
Signed-off-by: Bishop Brock <bcbrock@us.ibm.com>

orderer/README.md

@@ -29,3 +29,9 @@ There are currently no other raw ledgers available, although it is anticipated t
 To experiment with the orderer service you may build the orderer binary by simply typing `go build` in the `hyperledger/fabric/orderer` directory.  You may then invoke the orderer binary with no parameters, or you can override the bind address, port, and backing ledger by setting the environment variables `ORDERER_LISTEN_ADDRESS`, `ORDERER_LISTEN_PORT` and `ORDERER_LEDGER_TYPE` respectively.  Presently, only the solo orderer is supported.  The deployment and configuration is very stopgap at this point, so expect for this to change noticably in the future.
 
 There are sample clients in the `fabric/orderer/sample_clients` directory.  The `broadcast_timestamp` client sends a message containing the timestamp to the `Broadcast` service.  The `deliver_stdout` client prints received batches to stdout from the `Deliver` interface.  These may both be build simply by typing `go build` in their respective directories.  Neither presently supports config, so editing the source manually to adjust address and port is required.
+
+### Profiling
+
+Profiling the orderer service is possible through a standard HTTP interface documented [here](https://golang.org/pkg/net/http/pprof). The profiling service can be configured using the **config.yaml** file, or through environment variables. To enable profiling set `ORDERER_GENERAL_PROFILE_ENABLED=true`, and optionally set `ORDERER_GENERAL_PROFILE_ADDRESS` to the desired network address for the profiling service. The default address is `0.0.0.0:6060` as in the Golang documentation.
+
+Note that failures of the profiling service, either at startup or anytime during the run, will cause the overall orderer service to fail. Therefore it is currently not recommended to enable profiling in production settings.

orderer/config/config.go

@@ -48,6 +48,13 @@ type General struct {
 	ListenAddress string
 	ListenPort    uint16
 	GenesisMethod string
+	Profile       Profile
+}
+
+// Profile contains configuration for Go pprof profiling
+type Profile struct {
+	Enabled bool
+	Address string
 }
 
 // RAMLedger contains config for the RAM ledger
@@ -99,6 +106,10 @@ var defaults = TopLevel{
 		ListenAddress: "127.0.0.1",
 		ListenPort:    5151,
 		GenesisMethod: "static",
+		Profile: Profile{
+			Enabled: false,
+			Address: "0.0.0.0:6060",
+		},
 	},
 	RAMLedger: RAMLedger{
 		HistorySize: 10000,
@@ -150,6 +161,9 @@ func (c *TopLevel) completeInitialization() {
 			c.General.ListenPort = defaults.General.ListenPort
 		case c.General.GenesisMethod == "":
 			c.General.GenesisMethod = defaults.General.GenesisMethod
+		case c.General.Profile.Enabled && (c.General.Profile.Address == ""):
+			logger.Infof("Profiling enabled and General.Profile.Address unset, setting to %s", defaults.General.Profile.Address)
+			c.General.Profile.Address = defaults.General.Profile.Address
 		case c.FileLedger.Prefix == "":
 			logger.Infof("FileLedger.Prefix unset, setting to %s", defaults.FileLedger.Prefix)
 			c.FileLedger.Prefix = defaults.FileLedger.Prefix

orderer/main.go

@@ -22,6 +22,8 @@ import (
 	"io/ioutil"
 	"log"
 	"net"
+	"net/http"
+	_ "net/http/pprof"
 	"os"
 	"os/signal"
 
@@ -45,9 +47,20 @@ import (
 	"google.golang.org/grpc"
 )
 
+var logger = logging.MustGetLogger("orderer/main")
+
 func main() {
 	conf := config.Load()
 
+	// Start the profiling service if enabled. The ListenAndServe()
+	// call does not return unless an error occurs.
+	if conf.General.Profile.Enabled {
+		go func() {
+			logger.Infof("Starting Go pprof profiling service on %s", conf.General.Profile.Address)
+			panic(fmt.Errorf("Go pprof service failed: %s", http.ListenAndServe(conf.General.Profile.Address, nil)))
+		}()
+	}
+
 	switch conf.General.OrdererType {
 	case "solo":
 		launchSolo(conf)

orderer/orderer.yaml

@@ -41,6 +41,12 @@ General:
     # Genesis method: The method by which to retrieve/generate the genesis block
     GenesisMethod: static
 
+    # Enable an HTTP service for Go "pprof" profiling as documented at
+    # https://golang.org/pkg/net/http/pprof
+    Profile:
+        Enabled: false
+        Address: 0.0.0.0:6060
+
 ################################################################################
 #
 #   SECTION: RAM Ledger