Allow to set a soft memory limit for the binary itself

The setting debug.memory_limit_mbytes should not be used in conjuction
with debug.force_gc because the memory limit influences the garbage
collector.

app/api/api.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"io"
 	golog "log"
+	"math"
 	gonet "net"
 	gohttp "net/http"
 	"net/url"
@@ -1119,6 +1120,12 @@ func (a *api) start() error {
 		}(ctx)
 	}
 
+	if cfg.Debug.MemoryLimit > 0 {
+		debug.SetMemoryLimit(cfg.Debug.MemoryLimit * 1024 * 1024)
+	} else {
+		debug.SetMemoryLimit(math.MaxInt64)
+	}
+
 	// Start the restream processes
 	restream.Start()
 

config/config.go

@@ -232,6 +232,7 @@ func (d *Config) init() {
 	// Debug
 	d.vars.Register(value.NewBool(&d.Debug.Profiling, false), "debug.profiling", "CORE_DEBUG_PROFILING", nil, "Enable profiling endpoint on /profiling", false, false)
 	d.vars.Register(value.NewInt(&d.Debug.ForceGC, 0), "debug.force_gc", "CORE_DEBUG_FORCEGC", nil, "Number of seconds between forcing GC to return memory to the OS", false, false)
+	d.vars.Register(value.NewInt64(&d.Debug.MemoryLimit, 0), "debug.memory_limit_mbytes", "CORE_DEBUG_MEMORY_LIMIT_MBYTES", nil, "Impose a soft memory limit for the core, in megabytes", false, false)
 
 	// Metrics
 	d.vars.Register(value.NewBool(&d.Metrics.Enable, false), "metrics.enable", "CORE_METRICS_ENABLE", nil, "Enable collecting historic metrics data", false, false)

config/data.go

@@ -135,8 +135,9 @@ type Data struct {
 		MaxPort int  `json:"max_port"`
 	} `json:"playout"`
 	Debug struct {
-		Profiling bool `json:"profiling"`
+		Profiling   bool  `json:"profiling"`
-		ForceGC   int  `json:"force_gc"`
+		ForceGC     int   `json:"force_gc"`
+		MemoryLimit int64 `json:"memory_limit_mbytes"`
 	} `json:"debug"`
 	Metrics struct {
 		Enable           bool  `json:"enable"`
@@ -189,7 +190,6 @@ func MergeV2toV3(data *Data, d *v2.Data) (*Data, error) {
 	data.SRT = d.SRT
 	data.FFmpeg = d.FFmpeg
 	data.Playout = d.Playout
-	data.Debug = d.Debug
 	data.Metrics = d.Metrics
 	data.Sessions = d.Sessions
 	data.Service = d.Service
@@ -228,6 +228,10 @@ func MergeV2toV3(data *Data, d *v2.Data) (*Data, error) {
 	data.Storage.Memory = d.Storage.Memory
 
 	// Actual changes
+	data.Debug.Profiling = d.Debug.Profiling
+	data.Debug.ForceGC = d.Debug.ForceGC
+	data.Debug.MemoryLimit = 0
+
 	data.TLS.Enable = d.TLS.Enable
 	data.TLS.Address = d.TLS.Address
 	data.TLS.Auto = d.TLS.Auto
@@ -267,7 +271,6 @@ func DowngradeV3toV2(d *Data) (*v2.Data, error) {
 	data.SRT = d.SRT
 	data.FFmpeg = d.FFmpeg
 	data.Playout = d.Playout
-	data.Debug = d.Debug
 	data.Metrics = d.Metrics
 	data.Sessions = d.Sessions
 	data.Service = d.Service
@@ -299,6 +302,9 @@ func DowngradeV3toV2(d *Data) (*v2.Data, error) {
 	data.Router.Routes = copy.StringMap(d.Router.Routes)
 
 	// Actual changes
+	data.Debug.Profiling = d.Debug.Profiling
+	data.Debug.ForceGC = d.Debug.ForceGC
+
 	data.TLS.Enable = d.TLS.Enable
 	data.TLS.Address = d.TLS.Address
 	data.TLS.Auto = d.TLS.Auto