Added support for memory ballast

Author: foram-splunk

README.md

@@ -97,6 +97,7 @@ This is recommended for dev environments only.
 * `ENABLE_EVENT_TRACING`: Enables event trace logging. Splunk events will now contain a UUID, Splunk Nozzle Event Counts, and a Subscription-ID for Splunk correlation searches. (Default: false)
 * `STATUS_MONITOR_INTERVAL`: Time interval (in s/m/h. For example, 3600s or 60m or 1h) for monitoring memory queue pressure. Use to help with back-pressure insights. (Increases CPU load. Use for insights purposes only) Default is 0s (Disabled).
 * `DROP_WARN_THRESHOLD`: Threshold for the count of dropped events in case the downstream is slow. Based on the threshold, the errors will be logged.
+* `MEMORY_BALLAST_SIZE`: Size of memory allocated to reduce GC cycles. Default is 0, Size should be less than the total memory.
 
 __About app cache params:__
 

main.go

@@ -27,6 +27,11 @@ func main() {
 	signal.Notify(shutdownChan, syscall.SIGINT, syscall.SIGTERM)
 
 	config := splunknozzle.NewConfigFromCmdFlags(version, branch, commit, buildos)
+	if config.MemoryBallastSize > 0 {
+		ballast := make([]byte, config.MemoryBallastSize<<20)
+		_ = ballast
+	}
+
 	if config.AppCacheTTL == 0 && config.OrgSpaceCacheTTL > 0 {
 		logger.Info("Apps are not being cached. When apps are not cached, the org and space caching TTL is ineffective")
 	}

splunknozzle/config.go

@@ -56,6 +56,7 @@ type Config struct {
 	Debug                 bool          `json:"debug"`
 	StatusMonitorInterval time.Duration `json:"mem-queue-monitor-interval"`
 	DropWarnThreshold     int           `json:"drop-warn-threshold"`
+	MemoryBallastSize     int           `json:"memory-ballast-size"`
 }
 
 func NewConfigFromCmdFlags(version, branch, commit, buildos string) *Config {
@@ -138,6 +139,8 @@ func NewConfigFromCmdFlags(version, branch, commit, buildos string) *Config {
 		OverrideDefaultFromEnvar("STATUS_MONITOR_INTERVAL").Default("0s").DurationVar(&c.StatusMonitorInterval)
 	kingpin.Flag("drop-warn-threshold", "Log error with dropped events count at each threshold count due to slow downstream").
 		OverrideDefaultFromEnvar("DROP_WARN_THRESHOLD").Default("1000").IntVar(&c.DropWarnThreshold)
+	kingpin.Flag("memory-ballast-size", "Size of ballast in MB").
+		OverrideDefaultFromEnvar("MEMORY_BALLAST_SIZE").Default("0").IntVar(&c.MemoryBallastSize)
 
 	kingpin.Parse()
 	c.ApiEndpoint = strings.TrimSpace(c.ApiEndpoint)

splunknozzle/config_test.go

@@ -64,6 +64,7 @@ var _ = Describe("Config", func() {
 			os.Setenv("ENABLE_EVENT_TRACING", "true")
 			os.Setenv("DEBUG", "true")
 			os.Setenv("DROP_WARN_THRESHOLD", "100")
+			os.Setenv("MEMORY_BALLAST_SIZE", "512")
 
 			c := NewConfigFromCmdFlags(version, branch, commit, buildos)
 
@@ -110,6 +111,7 @@ var _ = Describe("Config", func() {
 			Expect(c.TraceLogging).To(BeTrue())
 			Expect(c.Debug).To(BeTrue())
 			Expect(c.DropWarnThreshold).To(Equal(100))
+			Expect(c.MemoryBallastSize).To(Equal(512))
 		})
 
 		It("check defaults", func() {
@@ -142,6 +144,7 @@ var _ = Describe("Config", func() {
 			Expect(c.TraceLogging).To(BeFalse())
 			Expect(c.Debug).To(BeFalse())
 			Expect(c.DropWarnThreshold).To(Equal(1000))
+			Expect(c.MemoryBallastSize).To(Equal(0))
 		})
 	})
 
@@ -188,6 +191,7 @@ var _ = Describe("Config", func() {
 				"--enable-event-tracing",
 				"--debug",
 				"--drop-warn-threshold=10",
+				"--memory-ballast-size=512",
 			}
 			os.Args = args
 		})
@@ -232,6 +236,7 @@ var _ = Describe("Config", func() {
 			Expect(c.Debug).To(BeTrue())
 			Expect(c.TraceLogging).To(BeTrue())
 			Expect(c.DropWarnThreshold).To(Equal(10))
+			Expect(c.MemoryBallastSize).To(Equal(512))
 
 			Expect(c.Version).To(Equal(version))
 			Expect(c.Branch).To(Equal(branch))

tile/tile.yml

@@ -199,6 +199,11 @@ forms:
     label: Drop Warn Threshold
     default: 1000
     description: Log error with dropped events count at each threshold count due to slow downstream
+  - name: memory_ballast_size
+    type: integer
+    label: Memory Ballast Size
+    default: 0
+    description: Size of memory allocated to reduce GC cycles. Default is 0, Size should be less than the total memory.
 
 migration: |
   if (typeof properties['properties']['.properties.add_app_info']['value'] == "boolean") {