BGP: Implement dynamic labels from descriptions (#249)

Co-authored-by: Oliver Geiselhardt-Herms <ogh@deepl.com>

collectors.go

@@ -3,6 +3,8 @@
 package main
 
 import (
+	"regexp"
+
 	"github.com/czerwonk/junos_exporter/internal/config"
 	"github.com/czerwonk/junos_exporter/pkg/collector"
 	"github.com/czerwonk/junos_exporter/pkg/connector"
@@ -44,13 +46,13 @@ import (
 
 type collectors struct {
 	logicalSystem string
-	dynamicLabels *interfacelabels.DynamicLabels
+	dynamicLabels *interfacelabels.DynamicLabelManager
 	collectors    map[string]collector.RPCCollector
 	devices       map[string][]collector.RPCCollector
 	cfg           *config.Config
 }
 
-func collectorsForDevices(devices []*connector.Device, cfg *config.Config, logicalSystem string, dynamicLabels *interfacelabels.DynamicLabels) *collectors {
+func collectorsForDevices(devices []*connector.Device, cfg *config.Config, logicalSystem string, dynamicLabels *interfacelabels.DynamicLabelManager) *collectors {
 	c := &collectors{
 		logicalSystem: logicalSystem,
 		dynamicLabels: dynamicLabels,
@@ -60,13 +62,13 @@ func collectorsForDevices(devices []*connector.Device, cfg *config.Config, logic
 	}
 
 	for _, d := range devices {
-		c.initCollectorsForDevices(d)
+		c.initCollectorsForDevices(d, cfg.IfDescReg)
 	}
 
 	return c
 }
 
-func (c *collectors) initCollectorsForDevices(device *connector.Device) {
+func (c *collectors) initCollectorsForDevices(device *connector.Device, bgpDescRe *regexp.Regexp) {
 	f := c.cfg.FeaturesForDevice(device.Host)
 
 	c.devices[device.Host] = make([]collector.RPCCollector, 0)
@@ -78,7 +80,7 @@ func (c *collectors) initCollectorsForDevices(device *connector.Device) {
 	})
 	c.addCollectorIfEnabledForDevice(device, "bfd", f.BFD, bfd.NewCollector)
 	c.addCollectorIfEnabledForDevice(device, "bgp", f.BGP, func() collector.RPCCollector {
-		return bgp.NewCollector(c.logicalSystem)
+		return bgp.NewCollector(c.logicalSystem, bgpDescRe)
 	})
 	c.addCollectorIfEnabledForDevice(device, "env", f.Environment, environment.NewCollector)
 	c.addCollectorIfEnabledForDevice(device, "firewall", f.Firewall, firewall.NewCollector)

collectors_test.go

@@ -40,7 +40,7 @@ func TestCollectorsRegistered(t *testing.T) {
 
 	cols := collectorsForDevices([]*connector.Device{{
 		Host: "::1",
-	}}, c, "", interfacelabels.NewDynamicLabels())
+	}}, c, "", interfacelabels.NewDynamicLabelManager())
 
 	assert.Equal(t, 20, len(cols.collectors), "collector count")
 }
@@ -88,7 +88,7 @@ func TestCollectorsForDevices(t *testing.T) {
 	d2 := &connector.Device{
 		Host: "2001:678:1e0::2",
 	}
-	cols := collectorsForDevices([]*connector.Device{d1, d2}, c, "", interfacelabels.NewDynamicLabels())
+	cols := collectorsForDevices([]*connector.Device{d1, d2}, c, "", interfacelabels.NewDynamicLabelManager())
 
 	assert.Equal(t, 20, len(cols.collectorsForDevice(d1)), "device 1 collector count")
 

devices.go

@@ -3,6 +3,7 @@
 package main
 
 import (
+	"fmt"
 	"os"
 	"regexp"
 	"strings"
@@ -56,10 +57,15 @@ func deviceFromDeviceConfig(device *config.DeviceConfig, hostname string, cfg *c
 	}
 
 	// check whether there is a device specific regex otherwise fallback to global regex
-	if len(device.IfDescReg) == 0 {
+	if len(device.IfDescRegStr) == 0 {
 		device.IfDescReg = cfg.IfDescReg
 	} else {
-		regexp.MustCompile(device.IfDescReg)
+		re, err := regexp.Compile(device.IfDescRegStr)
+		if err != nil {
+			return nil, fmt.Errorf("unable to compile device description regex for %q: %q: %w", hostname, device.IfDescRegStr, err)
+		}
+
+		device.IfDescReg = re
 	}
 
 	return &connector.Device{

internal/config/config.go

@@ -3,6 +3,7 @@
 package config
 
 import (
+	"fmt"
 	"io"
 	"regexp"
 
@@ -11,12 +12,26 @@ import (
 
 // Config represents the configuration for the exporter
 type Config struct {
-	Password  string          `yaml:"password"`
-	Targets   []string        `yaml:"targets,omitempty"`
-	Devices   []*DeviceConfig `yaml:"devices,omitempty"`
-	Features  FeatureConfig   `yaml:"features,omitempty"`
-	LSEnabled bool            `yaml:"logical_systems,omitempty"`
-	IfDescReg string          `yaml:"interface_description_regex,omitempty"`
+	Password    string          `yaml:"password"`
+	Targets     []string        `yaml:"targets,omitempty"`
+	Devices     []*DeviceConfig `yaml:"devices,omitempty"`
+	Features    FeatureConfig   `yaml:"features,omitempty"`
+	LSEnabled   bool            `yaml:"logical_systems,omitempty"`
+	IfDescReStr string          `yaml:"interface_description_regex,omitempty"`
+	IfDescReg   *regexp.Regexp  `yaml:"-"`
+}
+
+func (c *Config) load() error {
+	if c.IfDescReStr != "" {
+		re, err := regexp.Compile(c.IfDescReStr)
+		if err != nil {
+			return fmt.Errorf("unable to compile interfce description regex %q: %w", c.IfDescReStr, err)
+		}
+
+		c.IfDescReg = re
+	}
+
+	return nil
 }
 
 // DeviceConfig is the config representation of 1 device
@@ -27,7 +42,8 @@ type DeviceConfig struct {
 	KeyFile       string         `yaml:"key_file,omitempty"`
 	KeyPassphrase string         `yaml:"key_passphrase,omitempty"`
 	Features      *FeatureConfig `yaml:"features,omitempty"`
-	IfDescReg     string         `yaml:"interface_description_regex,omitempty"`
+	IfDescRegStr  string         `yaml:"interface_description_regex,omitempty"`
+	IfDescReg     *regexp.Regexp `yaml:"-"`
 	IsHostPattern bool           `yaml:"host_pattern,omitempty"`
 	HostPattern   *regexp.Regexp
 }
@@ -94,6 +110,11 @@ func Load(reader io.Reader) (*Config, error) {
 		return nil, err
 	}
 
+	err = c.load()
+	if err != nil {
+		return nil, err
+	}
+
 	for _, device := range c.Devices {
 		if device.IsHostPattern {
 			hostPattern, err := regexp.Compile(device.Host)
@@ -110,7 +131,6 @@ func Load(reader io.Reader) (*Config, error) {
 func setDefaultValues(c *Config) {
 	c.Password = ""
 	c.LSEnabled = false
-	c.IfDescReg = ""
 	f := &c.Features
 	f.Alarm = true
 	f.BGP = true

junos_collector.go

@@ -40,7 +40,7 @@ type junosCollector struct {
 }
 
 func newJunosCollector(ctx context.Context, devices []*connector.Device, logicalSystem string) *junosCollector {
-	l := interfacelabels.NewDynamicLabels()
+	l := interfacelabels.NewDynamicLabelManager()
 
 	clients := make(map[*connector.Device]*rpc.Client)
 
@@ -78,22 +78,13 @@ func newJunosCollector(ctx context.Context, devices []*connector.Device, logical
 func deviceInterfaceRegex(host string) *regexp.Regexp {
 	dc := cfg.FindDeviceConfig(host)
 
-	if len(dc.IfDescReg) > 0 {
-		regex, err := regexp.Compile(dc.IfDescReg)
+	if len(dc.IfDescRegStr) > 0 {
+		regex, err := regexp.Compile(dc.IfDescRegStr)
 		if err == nil {
 			return regex
 		}
 
-		log.Errorf("device specific dynamic label regex %s invalid: %v", dc.IfDescReg, err)
-	}
-
-	if len(cfg.IfDescReg) > 0 {
-		regex, err := regexp.Compile(cfg.IfDescReg)
-		if err == nil {
-			return regex
-		}
-
-		log.Errorf("global dynamic label regex (%s) invalid: %v", cfg.IfDescReg, err)
+		log.Errorf("device specific dynamic label regex %s invalid: %v", dc.IfDescRegStr, err)
 	}
 
 	return interfacelabels.DefaultInterfaceDescRegex()

main.go

@@ -212,7 +212,7 @@ func loadConfigFromFlags() *config.Config {
 	c := config.New()
 	c.Targets = strings.Split(*sshHosts, ",")
 	c.LSEnabled = *lsEnabled
-	c.IfDescReg = *interfaceDescriptionRegex
+	c.IfDescReStr = *interfaceDescriptionRegex
 
 	f := &c.Features
 	f.Alarm = *alarmEnabled