band-aid fix to avoid random window faults

cr: https://code.amazon.com/reviews/CR-54083211

README.md

@@ -216,6 +216,8 @@ To set up your own custom configuration for the agent:
         * Default: 7
     * LongRunningWorkerMonitorIntervalSeconds (int)
         * Default: 60
+    * GoMaxProcForAgentWorker (int)
+        * Default: 0
 * Os - represents os related information, will be logged in reply messages
     * Lang (string)
         * Default: "en-US"

agent/agent_unix.go

@@ -2,9 +2,18 @@
 
 package main
 
-import logger "github.com/aws/amazon-ssm-agent/agent/log/ssmlog"
+import (
+	"runtime"
+
+	"github.com/aws/amazon-ssm-agent/agent/appconfig"
+	logger "github.com/aws/amazon-ssm-agent/agent/log/ssmlog"
+)
 
 func main() {
+	config, _ := appconfig.Config(false)
+	// will use default when the value is less than one
+	runtime.GOMAXPROCS(config.Agent.GoMaxProcForAgentWorker)
+
 	// initialize logger
 	log := logger.SSMLogger(true)
 	defer log.Close()

agent/agent_windows.go

@@ -3,6 +3,9 @@
 package main
 
 import (
+	"runtime"
+
+	"github.com/aws/amazon-ssm-agent/agent/appconfig"
 	"github.com/aws/amazon-ssm-agent/agent/log/ssmlog"
 	"github.com/aws/amazon-ssm-agent/agent/longrunning/plugin/cloudwatch"
 )
@@ -11,6 +14,10 @@ const serviceName = "AmazonSSMAgent"
 const imageStateComplete = "IMAGE_STATE_COMPLETE"
 
 func main() {
+	config, _ := appconfig.Config(false)
+	// will use default when the value is less than one
+	runtime.GOMAXPROCS(config.Agent.GoMaxProcForAgentWorker)
+
 	// initialize logger
 	log := ssmlog.SSMLogger(true)
 	defer log.Close()

agent/appconfig/appconfig.go

@@ -127,6 +127,7 @@ func DefaultConfig() SsmagentConfig {
 		AuditExpirationDay:                      DefaultAuditExpirationDay,
 		LongRunningWorkerMonitorIntervalSeconds: defaultLongRunningWorkerMonitorIntervalSeconds,
 		ForceFileIPC:                            false,
+		GoMaxProcForAgentWorker:                 0,
 	}
 	var os = OsInfo{
 		Lang:    "en-US",

agent/appconfig/appconfig_parser.go

@@ -17,6 +17,7 @@ package appconfig
 
 import (
 	"log"
+	"runtime"
 )
 
 //func parser(config *T) {
@@ -45,6 +46,11 @@ func parser(config *SsmagentConfig) {
 		DefaultSsmSelfUpdateFrequencyDaysMin,
 		DefaultSsmSelfUpdateFrequencyDaysMax,
 		DefaultSsmSelfUpdateFrequencyDays)
+	config.Agent.GoMaxProcForAgentWorker = getNumericValue(config.Agent.GoMaxProcForAgentWorker,
+		1,
+		runtime.NumCPU(),
+		0)
+
 	config.Agent.AuditExpirationDay = getNumericValue(
 		config.Agent.AuditExpirationDay,
 		DefaultAuditExpirationDayMin,

agent/appconfig/contracts.go

@@ -68,6 +68,8 @@ type AgentInfo struct {
 	LongRunningWorkerMonitorIntervalSeconds int
 	AuditExpirationDay                      int
 	ForceFileIPC                            bool
+	// denotes GOMAXPROCS value for legacy agent worker
+	GoMaxProcForAgentWorker int
 }
 
 // MgsConfig represents configuration for Message Gateway service