an optional config file and a new HTTP query string to override walk param

config/config.go

@@ -16,6 +16,7 @@ package config
 import (
 	"fmt"
 	"io/ioutil"
+	"os"
 	"regexp"
 	"time"
 
@@ -36,6 +37,23 @@ func LoadFile(filename string) (*Config, error) {
 	return cfg, nil
 }
 
+func LoadWalkParamFile(filename string) (WalkConfig, error) {
+	content, err := ioutil.ReadFile(filename)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return WalkConfig{}, nil
+		}
+		return nil, err
+	}
+	cfg := WalkConfig{}
+	err = yaml.UnmarshalStrict(content, &cfg)
+	if err != nil {
+		return nil, err
+	}
+
+	return cfg, nil
+}
+
 var (
 	DefaultAuth = Auth{
 		Community:     "public",
@@ -61,6 +79,8 @@ var (
 // Config for the snmp_exporter.
 type Config map[string]*Module
 
+type WalkConfig map[string]*WalkParams
+
 type WalkParams struct {
 	Version        int           `yaml:"version,omitempty"`
 	MaxRepetitions uint8         `yaml:"max_repetitions,omitempty"`
@@ -77,6 +97,47 @@ type Module struct {
 	WalkParams WalkParams `yaml:",inline"`
 }
 
+func (c *WalkParams) UnmarshalYAML(unmarshal func(interface{}) error) error {
+	*c = DefaultWalkParams
+	type plain WalkParams
+	if err := unmarshal((*plain)(c)); err != nil {
+		return err
+	}
+
+	wp := c
+
+	if wp.Version < 1 || wp.Version > 3 {
+		return fmt.Errorf("SNMP version must be 1, 2 or 3. Got: %d", wp.Version)
+	}
+	if wp.Version == 3 {
+		switch wp.Auth.SecurityLevel {
+		case "authPriv":
+			if wp.Auth.PrivPassword == "" {
+				return fmt.Errorf("priv password is missing, required for SNMPv3 with priv")
+			}
+			if wp.Auth.PrivProtocol != "DES" && wp.Auth.PrivProtocol != "AES" {
+				return fmt.Errorf("priv protocol must be DES or AES")
+			}
+			fallthrough
+		case "authNoPriv":
+			if wp.Auth.Password == "" {
+				return fmt.Errorf("auth password is missing, required for SNMPv3 with auth")
+			}
+			if wp.Auth.AuthProtocol != "MD5" && wp.Auth.AuthProtocol != "SHA" {
+				return fmt.Errorf("auth protocol must be SHA or MD5")
+			}
+			fallthrough
+		case "noAuthNoPriv":
+			if wp.Auth.Username == "" {
+				return fmt.Errorf("auth username is missing, required for SNMPv3")
+			}
+		default:
+			return fmt.Errorf("security level must be one of authPriv, authNoPriv or noAuthNoPriv")
+		}
+	}
+	return nil
+}
+
 func (c *Module) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	*c = DefaultModule
 	type plain Module
@@ -95,15 +156,15 @@ func (c *Module) UnmarshalYAML(unmarshal func(interface{}) error) error {
 			if wp.Auth.PrivPassword == "" {
 				return fmt.Errorf("priv password is missing, required for SNMPv3 with priv")
 			}
-			if wp.Auth.PrivProtocol != "DES" && wp.Auth.PrivProtocol != "AES" && wp.Auth.PrivProtocol != "AES192" && wp.Auth.PrivProtocol != "AES256" {
+			if wp.Auth.PrivProtocol != "DES" && wp.Auth.PrivProtocol != "AES" {
 				return fmt.Errorf("priv protocol must be DES or AES")
 			}
 			fallthrough
 		case "authNoPriv":
 			if wp.Auth.Password == "" {
 				return fmt.Errorf("auth password is missing, required for SNMPv3 with auth")
 			}
-			if wp.Auth.AuthProtocol != "MD5" && wp.Auth.AuthProtocol != "SHA" && wp.Auth.AuthProtocol != "SHA224" && wp.Auth.AuthProtocol != "SHA256" && wp.Auth.AuthProtocol != "SHA384" && wp.Auth.AuthProtocol != "SHA512" {
+			if wp.Auth.AuthProtocol != "MD5" && wp.Auth.AuthProtocol != "SHA" {
 				return fmt.Errorf("auth protocol must be SHA or MD5")
 			}
 			fallthrough
@@ -153,14 +214,6 @@ func (c WalkParams) ConfigureSNMP(g *gosnmp.GoSNMP) {
 		switch c.Auth.AuthProtocol {
 		case "SHA":
 			usm.AuthenticationProtocol = gosnmp.SHA
-		case "SHA224":
-			usm.AuthenticationProtocol = gosnmp.SHA224
-		case "SHA256":
-			usm.AuthenticationProtocol = gosnmp.SHA256
-		case "SHA384":
-			usm.AuthenticationProtocol = gosnmp.SHA384
-		case "SHA512":
-			usm.AuthenticationProtocol = gosnmp.SHA512
 		case "MD5":
 			usm.AuthenticationProtocol = gosnmp.MD5
 		}
@@ -172,10 +225,6 @@ func (c WalkParams) ConfigureSNMP(g *gosnmp.GoSNMP) {
 			usm.PrivacyProtocol = gosnmp.DES
 		case "AES":
 			usm.PrivacyProtocol = gosnmp.AES
-		case "AES192":
-			usm.PrivacyProtocol = gosnmp.AES192
-		case "AES256":
-			usm.PrivacyProtocol = gosnmp.AES256
 		}
 	}
 	g.SecurityParameters = usm

main.go

@@ -30,19 +30,17 @@ import (
 	"github.com/prometheus/common/promlog"
 	"github.com/prometheus/common/promlog/flag"
 	"github.com/prometheus/common/version"
-	"github.com/prometheus/exporter-toolkit/web"
-	webflag "github.com/prometheus/exporter-toolkit/web/kingpinflag"
 	"gopkg.in/alecthomas/kingpin.v2"
 	yaml "gopkg.in/yaml.v2"
 
 	"github.com/prometheus/snmp_exporter/config"
 )
 
 var (
-	configFile    = kingpin.Flag("config.file", "Path to configuration file.").Default("snmp.yml").String()
-	webConfig     = webflag.AddFlags(kingpin.CommandLine)
-	listenAddress = kingpin.Flag("web.listen-address", "Address to listen on for web interface and telemetry.").Default(":9116").String()
-	dryRun        = kingpin.Flag("dry-run", "Only verify configuration is valid and exit.").Default("false").Bool()
+	walkParamConfigFile = kingpin.Flag("config.walkParam", "path to optional walk param configuration file").Default("wp.yml").String()
+	configFile          = kingpin.Flag("config.file", "Path to configuration file.").Default("snmp.yml").String()
+	listenAddress       = kingpin.Flag("web.listen-address", "Address to listen on for web interface and telemetry.").Default(":9116").String()
+	dryRun              = kingpin.Flag("dry-run", "Only verify configuration is valid and exit.").Default("false").Bool()
 
 	// Metrics about the SNMP exporter itself.
 	snmpDuration = prometheus.NewSummaryVec(
@@ -98,7 +96,28 @@ func handler(w http.ResponseWriter, r *http.Request, logger log.Logger) {
 		return
 	}
 
-	logger = log.With(logger, "module", moduleName, "target", target)
+	var wpName = query.Get("walkParam")
+	if len(query["walkParaM"]) > 1 {
+		http.Error(w, "'walkParam' parameter must only be specified once", 400)
+		snmpRequestErrors.Inc()
+		return
+	}
+	if wpName == "" {
+		//nothing to do
+	} else {
+		if wp, exist := sc.wp[wpName]; exist == false {
+			http.Error(w, fmt.Sprintf("unknown 'walkParam' parameter '%v'", wpName), 400)
+			snmpRequestErrors.Inc()
+			return
+		} else {
+			module.WalkParams = *wp
+		}
+	}
+	if wpName == "" {
+		logger = log.With(logger, "module", moduleName, "target", target)
+	} else {
+		logger = log.With(logger, "module", moduleName, "walkParam", wpName, "target", target)
+	}
 	level.Debug(logger).Log("msg", "Starting scrape")
 
 	start := time.Now()
@@ -128,16 +147,22 @@ func updateConfiguration(w http.ResponseWriter, r *http.Request) {
 
 type SafeConfig struct {
 	sync.RWMutex
-	C *config.Config
+	C  *config.Config
+	wp config.WalkConfig
 }
 
 func (sc *SafeConfig) ReloadConfig(configFile string) (err error) {
 	conf, err := config.LoadFile(configFile)
 	if err != nil {
 		return err
 	}
+	wp, err := config.LoadWalkParamFile(*walkParamConfigFile)
+	if err != nil {
+		return err
+	}
 	sc.Lock()
 	sc.C = conf
+	sc.wp = wp
 	sc.Unlock()
 	return nil
 }
@@ -159,6 +184,11 @@ func main() {
 		level.Error(logger).Log("msg", "Error parsing config file", "err", err)
 		os.Exit(1)
 	}
+	sc.wp, err = config.LoadWalkParamFile(*walkParamConfigFile)
+	if err != nil {
+		level.Error(logger).Log("msg", "Error parsing config file", "err", err)
+		os.Exit(1)
+	}
 
 	// Exit if in dry-run mode.
 	if *dryRun {
@@ -244,8 +274,7 @@ func main() {
 	})
 
 	level.Info(logger).Log("msg", "Listening on address", "address", *listenAddress)
-	srv := &http.Server{Addr: *listenAddress}
-	if err := web.ListenAndServe(srv, *webConfig, logger); err != nil {
+	if err := http.ListenAndServe(*listenAddress, nil); err != nil {
 		level.Error(logger).Log("msg", "Error starting HTTP server", "err", err)
 		os.Exit(1)
 	}