feat: add runtime modification of log level using config file

cmd/config/config.go

@@ -3,6 +3,7 @@ package config
 import (
 	"log"
 
+	"github.com/fsnotify/fsnotify"
 	"github.com/go-playground/validator/v10"
 	"github.com/spf13/pflag"
 	"github.com/spf13/viper"
@@ -11,21 +12,21 @@ import (
 var v = viper.GetViper()
 
 type UpfConfig struct {
-	InterfaceName     []string `mapstructure:"interface_name"`
-	XDPAttachMode     string   `mapstructure:"xdp_attach_mode" validate:"oneof=generic native offload"`
-	ApiAddress        string   `mapstructure:"api_address" validate:"hostname_port"`
-	PfcpAddress       string   `mapstructure:"pfcp_address" validate:"hostname_port"`
-	PfcpNodeId        string   `mapstructure:"pfcp_node_id" validate:"hostname|ip"`
-	MetricsAddress    string   `mapstructure:"metrics_address" validate:"hostname_port"`
-	N3Address         string   `mapstructure:"n3_address" validate:"ipv4"`
-	QerMapSize        uint32   `mapstructure:"qer_map_size" validate:"min=1"`
-	FarMapSize        uint32   `mapstructure:"far_map_size" validate:"min=1"`
-	PdrMapSize        uint32   `mapstructure:"pdr_map_size" validate:"min=1"`
-	EbpfMapResize     bool     `mapstructure:"resize_ebpf_maps"`
-	HeartbeatRetries  uint32   `mapstructure:"heartbeat_retries"`
-	HeartbeatInterval uint32   `mapstructure:"heartbeat_interval"`
-	HeartbeatTimeout  uint32   `mapstructure:"heartbeat_timeout"`
-	LoggingLevel      string   `mapstructure:"logging_level"`
+	InterfaceName     []string `mapstructure:"interface_name" json:"interface_name"`
+	XDPAttachMode     string   `mapstructure:"xdp_attach_mode" validate:"oneof=generic native offload" json:"xdp_attach_mode"`
+	ApiAddress        string   `mapstructure:"api_address" validate:"hostname_port" json:"api_address"`
+	PfcpAddress       string   `mapstructure:"pfcp_address" validate:"hostname_port" json:"pfcp_address"`
+	PfcpNodeId        string   `mapstructure:"pfcp_node_id" validate:"hostname|ip" json:"pfcp_node_id"`
+	MetricsAddress    string   `mapstructure:"metrics_address" validate:"hostname_port" json:"metrics_address"`
+	N3Address         string   `mapstructure:"n3_address" validate:"ipv4" json:"n3_address"`
+	QerMapSize        uint32   `mapstructure:"qer_map_size" validate:"min=1" json:"qer_map_size"`
+	FarMapSize        uint32   `mapstructure:"far_map_size" validate:"min=1" json:"far_map_size"`
+	PdrMapSize        uint32   `mapstructure:"pdr_map_size" validate:"min=1" json:"pdr_map_size"`
+	EbpfMapResize     bool     `mapstructure:"resize_ebpf_maps" json:"resize_ebpf_maps"`
+	HeartbeatRetries  uint32   `mapstructure:"heartbeat_retries" json:"heartbeat_retries"`
+	HeartbeatInterval uint32   `mapstructure:"heartbeat_interval" json:"heartbeat_interval"`
+	HeartbeatTimeout  uint32   `mapstructure:"heartbeat_timeout" json:"heartbeat_timeout"`
+	LoggingLevel      string   `mapstructure:"logging_level" validate:"required" json:"logging_level"`
 }
 
 func init() {
@@ -86,8 +87,11 @@ func init() {
 	v.SetEnvPrefix("upf")
 	v.AutomaticEnv()
 
+	configFileAvailable = true
+
 	if err := v.ReadInConfig(); err != nil {
 		log.Printf("Unable to read config file, %v", err)
+		configFileAvailable = false
 	}
 
 	log.Printf("Get raw config: %+v", v.AllSettings())
@@ -101,3 +105,12 @@ func (c *UpfConfig) Validate() error {
 func (c *UpfConfig) Unmarshal() error {
 	return v.UnmarshalExact(c)
 }
+
+var configFileAvailable bool
+
+func SetWatchConfig(onConfigChange func(e fsnotify.Event)) {
+	if configFileAvailable {
+		viper.OnConfigChange(onConfigChange)
+		viper.WatchConfig()
+	}
+}

cmd/config/startup.go

@@ -18,3 +18,19 @@ func Init() {
 
 	log.Printf("Apply eUPF config: %+v", Conf)
 }
+
+func GetUpdatedConf() (UpfConfig, error) {
+	var updatedConf UpfConfig
+	if err := updatedConf.Unmarshal(); err != nil {
+		log.Fatalf("Unable to decode into struct, %v", err)
+		return UpfConfig{}, err
+	}
+
+	if err := updatedConf.Validate(); err != nil {
+		log.Fatalf("eUPF config is invalid: %v", err)
+		return UpfConfig{}, err
+	}
+
+	log.Printf("Apply updated eUPF config: %+v", updatedConf)
+	return updatedConf, nil
+}

cmd/core/api.go

@@ -1,14 +1,15 @@
 package core
 
 import (
+	"fmt"
 	"net"
 	"net/http"
 	"strconv"
 	"unsafe"
 
+	"github.com/edgecomllc/eupf/cmd/config"
 	"github.com/edgecomllc/eupf/cmd/ebpf"
 
-	"github.com/edgecomllc/eupf/cmd/config"
 	eupfDocs "github.com/edgecomllc/eupf/cmd/docs"
 	"github.com/gin-contrib/cors"
 	"github.com/gin-gonic/gin"
@@ -33,10 +34,15 @@ func CreateApiServer(bpfObjects *ebpf.BpfObjects, pfcpSrv *PfcpConnection, forwa
 	v1 := router.Group("/api/v1")
 	{
 		v1.GET("upf_pipeline", ListUpfPipeline(bpfObjects))
-		v1.GET("config", DisplayConfig())
 		v1.GET("xdp_stats", DisplayXdpStatistics(forwardPlaneStats))
 		v1.GET("packet_stats", DisplayPacketStats(forwardPlaneStats))
 
+		config := v1.Group("config")
+		{
+			config.GET("", DisplayConfig())
+			config.POST("", EditConfig)
+		}
+
 		qerMap := v1.Group("qer_map")
 		{
 			qerMap.GET("", ListQerMapContent(bpfObjects))
@@ -60,6 +66,24 @@ func CreateApiServer(bpfObjects *ebpf.BpfObjects, pfcpSrv *PfcpConnection, forwa
 	return &ApiServer{router: router}
 }
 
+func EditConfig(c *gin.Context) {
+	var conf config.UpfConfig
+	if err := c.BindJSON(&conf); err != nil {
+		c.IndentedJSON(http.StatusBadRequest, gin.H{
+			"message":       "Request body json has incorrect format. Use one or more fields from the following structure",
+			"correctFormat": config.UpfConfig{},
+		})
+		return
+	}
+	if err := SetConfig(conf); err != nil {
+		c.IndentedJSON(http.StatusBadRequest, gin.H{
+			"message": fmt.Sprintf("Error during editing config: %s", err.Error()),
+		})
+	} else {
+		c.Status(http.StatusOK)
+	}
+}
+
 type PacketStats struct {
 	RxArp      uint64 `json:"rx_arp"`
 	RxIcmp     uint64 `json:"rx_icmp"`

cmd/core/config_edit.go

@@ -0,0 +1,18 @@
+package core
+
+import (
+	"fmt"
+
+	"github.com/edgecomllc/eupf/cmd/config"
+
+	"github.com/rs/zerolog"
+)
+
+func SetConfig(conf config.UpfConfig) error {
+	// For now only logging_level parameter update in config.UpfConfig is supported.
+	if err := SetLoggerLevel(conf.LoggingLevel); err != nil {
+		return fmt.Errorf("Logger configuring error: %s. Using '%s' level",
+			err.Error(), zerolog.GlobalLevel().String())
+	}
+	return nil
+}

cmd/core/logger.go

@@ -0,0 +1,28 @@
+package core
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/edgecomllc/eupf/cmd/config"
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/log"
+)
+
+func InitLogger() {
+	output := zerolog.ConsoleWriter{Out: os.Stdout, TimeFormat: "2006/01/02 15:04:05"}
+	log.Logger = zerolog.New(output).With().Timestamp().Logger()
+}
+
+func SetLoggerLevel(loggingLevel string) error {
+	if loggingLevel == "" {
+		return fmt.Errorf("Logging level can't be empty")
+	}
+	if loglvl, err := zerolog.ParseLevel(loggingLevel); err == nil {
+		zerolog.SetGlobalLevel(loglvl)
+		config.Conf.LoggingLevel = zerolog.GlobalLevel().String()
+	} else {
+		return fmt.Errorf("Can't parse logging level: '%s'", loggingLevel)
+	}
+	return nil
+}

cmd/main.go

@@ -9,6 +9,7 @@ import (
 
 	"github.com/edgecomllc/eupf/cmd/core"
 	"github.com/edgecomllc/eupf/cmd/ebpf"
+	"github.com/fsnotify/fsnotify"
 
 	"github.com/cilium/ebpf/link"
 	"github.com/edgecomllc/eupf/cmd/config"
@@ -27,7 +28,10 @@ func main() {
 
 	// Warning: inefficient log writing.
 	// As zerolog docs says: "Pretty logging on the console is made possible using the provided (but inefficient) zerolog.ConsoleWriter."
-	ConfigureLogger()
+	core.InitLogger()
+	if err := core.SetLoggerLevel(config.Conf.LoggingLevel); err != nil {
+		log.Error().Msgf("Logger configuring error: %s. Using '%s' level", err.Error(), zerolog.GlobalLevel().String())
+	}
 
 	if err := ebpf.IncreaseResourceLimits(); err != nil {
 		log.Fatal().Msgf("Can't increase resource limits: %s", err.Error())
@@ -104,6 +108,9 @@ func main() {
 		}
 	}()
 
+	// Handle config file change.
+	config.SetWatchConfig(OnConfigFileChange)
+
 	// Print the contents of the BPF hash map (source IP address -> packet count).
 	ticker := time.NewTicker(5 * time.Second)
 	defer ticker.Stop()
@@ -137,13 +144,12 @@ func StringToXDPAttachMode(Mode string) link.XDPAttachFlags {
 	}
 }
 
-func ConfigureLogger() {
-	output := zerolog.ConsoleWriter{Out: os.Stdout, TimeFormat: "2006/01/02 15:04:05"}
-	log.Logger = zerolog.New(output).With().Timestamp().Logger()
-
-	if loglvl, err := zerolog.ParseLevel(config.Conf.LoggingLevel); err == nil {
-		zerolog.SetGlobalLevel(loglvl)
-	} else {
-		log.Warn().Msgf("Can't parse logging level: %s. Using \"info\" level.", err.Error())
+func OnConfigFileChange(e fsnotify.Event) {
+	if e.Has(fsnotify.Create) || e.Has(fsnotify.Write) {
+		if conf, err := config.GetUpdatedConf(); err == nil {
+			if err := core.SetConfig(conf); err != nil {
+				log.Error().Msgf("Error during config file change handling: %s", err.Error())
+			}
+		}
 	}
 }