inlet/snmp: do not deprecate default-community

We did not handle all cases, notably the case where default-community
was not set explicitely by the user. This seems a lot of code for
little gain, let's keep things simple.

common/helpers/subnetmap.go

@@ -24,7 +24,7 @@ type SubnetMap[V any] struct {
 // Lookup will search for the most specific subnet matching the
 // provided IP address and return the value associated with it.
 func (sm *SubnetMap[V]) Lookup(ip net.IP) (V, bool) {
-	if sm.tree == nil {
+	if sm == nil || sm.tree == nil {
 		var value V
 		return value, false
 	}

console/data/docs/00-intro.md

@@ -40,8 +40,8 @@ documentation.
 
 - `clickhouse` → `asns` to give names to your internal AS numbers
 - `clickhouse` → `networks` to attach attributes to your networks
-- `inlet` → `snmp` → `communities` to set the communities to use for
+- `inlet` → `snmp` → `default-community` to set the default community
-  SNMP queries
+  to use for SNMP queries
 - `inlet` → `core` → `exporter-classifiers` to define rules to attach
   attributes to your exporters
 - `inlet` → `core` → `interface-classifiers` to define rules to attach

console/data/docs/02-configuration.md

@@ -255,10 +255,10 @@ continuously the exporters. The following keys are accepted:
   about to expire or need an update
 - `cache-persist-file` tells where to store cached data on shutdown and
   read them back on startup
+- `default-community` tells which community to use when polling exporters
 - `communities` is a map from a subnets to the community to use for
-  exporters in the provided subnet. Use `::/0` to set the default
+  exporters in the provided subnet, overriding the default value
-  value. Alternatively, it also accepts a string to use for all
+  above.
-  exporters.
 - `poller-retries` is the number of retries on unsuccessful SNMP requests.
 - `poller-timeout` tells how much time should the poller wait for an answer.
 - `workers` tell how many workers to spawn to handle SNMP polling.

console/data/docs/99-changelog.md

@@ -23,7 +23,7 @@ details.
 - 🩹 *orchestrator*: fix `SrcCountry`/`DstCountry` columns in aggregated tables [PR #61][]
 - 🌱 *inlet*: `inlet.geoip.country-database` has been renamed to `inlet.geoip.geo-database`
 - 🌱 *inlet*: add counters for GeoIP database hit/miss
-- 🌱 *inlet*: `inlet.snmp.communities` accepts subnets as keys, `inlet.snmp.default-community` is now deprecated
+- 🌱 *inlet*: `inlet.snmp.communities` accepts subnets as keys
 - 🌱 *docker-compose*: disable healthcheck for the conntrack-fixer container
 
 [PR #61]: https://github.com/vincentbernat/akvorado/pull/61

inlet/snmp/config.go

@@ -4,12 +4,9 @@
 package snmp
 
 import (
-	"reflect"
 	"time"
 
 	"akvorado/common/helpers"
-
-	"github.com/mitchellh/mapstructure"
 )
 
 // Configuration describes the configuration for the SNMP client
@@ -22,6 +19,8 @@ type Configuration struct {
 	CacheCheckInterval time.Duration `validate:"ltefield=CacheRefresh"`
 	// CachePersist defines a file to store cache and survive restarts
 	CachePersistFile string
+	// DefaultCommunity is the default SNMP community to use
+	DefaultCommunity string `validate:"required"`
 	// Communities is a mapping from exporter IPs to communities
 	Communities *helpers.SubnetMap[string]
 	// PollerRetries tell how many time a poller should retry before giving up
@@ -36,18 +35,12 @@ type Configuration struct {
 
 // DefaultConfiguration represents the default configuration for the SNMP client.
 func DefaultConfiguration() Configuration {
-	communities, err := helpers.NewSubnetMap(map[string]string{
-		"::/0": "public",
-	})
-	if err != nil {
-		panic(err)
-	}
 	return Configuration{
 		CacheDuration:      30 * time.Minute,
 		CacheRefresh:       time.Hour,
 		CacheCheckInterval: 2 * time.Minute,
 		CachePersistFile:   "",
-		Communities:        communities,
+		DefaultCommunity:   "public",
 		PollerRetries:      1,
 		PollerTimeout:      time.Second,
 		PollerCoalesce:     10,
@@ -55,42 +48,6 @@ func DefaultConfiguration() Configuration {
 	}
 }
 
-// ConfigurationUnmarshallerHook normalize SNMP configuration:
-//  - append default-community to communities (as ::/0)
-func ConfigurationUnmarshallerHook() mapstructure.DecodeHookFunc {
-	return func(from, to reflect.Value) (interface{}, error) {
-		if from.Kind() != reflect.Map || from.IsNil() || from.Type().Key().Kind() != reflect.String || to.Type() != reflect.TypeOf(Configuration{}) {
-			return from.Interface(), nil
-		}
-
-		// default-community → communities
-		var defaultKey, mapKey *reflect.Value
-		fromMap := from.MapKeys()
-		for i, k := range fromMap {
-			if helpers.MapStructureMatchName(k.String(), "DefaultCommunity") {
-				defaultKey = &fromMap[i]
-			} else if helpers.MapStructureMatchName(k.String(), "Communities") {
-				mapKey = &fromMap[i]
-			}
-		}
-		if defaultKey != nil {
-			if mapKey == nil {
-				from.SetMapIndex(reflect.ValueOf("communities"), from.MapIndex(*defaultKey))
-			} else {
-				communities := from.MapIndex(*mapKey)
-				if communities.Kind() == reflect.Interface {
-					communities = communities.Elem()
-				}
-				communities.SetMapIndex(reflect.ValueOf("::/0"), from.MapIndex(*defaultKey))
-			}
-			from.SetMapIndex(*defaultKey, reflect.Value{})
-		}
-
-		return from.Interface(), nil
-	}
-}
-
 func init() {
-	helpers.AddMapstructureUnmarshallerHook(ConfigurationUnmarshallerHook())
 	helpers.AddMapstructureUnmarshallerHook(helpers.SubnetMapUnmarshallerHook[string]())
 }

inlet/snmp/config_test.go

@@ -5,12 +5,8 @@ package snmp
 
 import (
 	"testing"
-	"time"
 
 	"akvorado/common/helpers"
-
-	"github.com/gin-gonic/gin"
-	"github.com/mitchellh/mapstructure"
 )
 
 func TestDefaultConfiguration(t *testing.T) {
@@ -18,84 +14,3 @@ func TestDefaultConfiguration(t *testing.T) {
 		t.Fatalf("validate.Struct() error:\n%+v", err)
 	}
 }
-
-func TestConfigurationUnmarshallerHook(t *testing.T) {
-	cases := []struct {
-		Description string
-		Input       gin.H
-		Output      Configuration
-	}{
-		{
-			Description: "nil",
-			Input:       nil,
-		}, {
-			Description: "empty",
-			Input:       gin.H{},
-		}, {
-			Description: "no communities, no default community",
-			Input: gin.H{
-				"cache-refresh":  "10s",
-				"poller-retries": 10,
-			},
-			Output: Configuration{
-				CacheRefresh:  10 * time.Second,
-				PollerRetries: 10,
-			},
-		}, {
-			Description: "communities, no default community",
-			Input: gin.H{
-				"communities": gin.H{
-					"203.0.113.0/25":   "public",
-					"203.0.113.128/25": "private",
-				},
-			},
-			Output: Configuration{
-				Communities: helpers.MustNewSubnetMap(map[string]string{
-					"::ffff:203.0.113.0/121":   "public",
-					"::ffff:203.0.113.128/121": "private",
-				}),
-			},
-		}, {
-			Description: "no communities, default community",
-			Input: gin.H{
-				"default-community": "private",
-			},
-			Output: Configuration{
-				Communities: helpers.MustNewSubnetMap(map[string]string{
-					"::/0": "private",
-				}),
-			},
-		}, {
-			Description: "communities, default community",
-			Input: gin.H{
-				"default-community": "private",
-				"communities": gin.H{
-					"203.0.113.0/25":   "public",
-					"203.0.113.128/25": "private",
-				},
-			},
-			Output: Configuration{
-				Communities: helpers.MustNewSubnetMap(map[string]string{
-					"::/0":                     "private",
-					"::ffff:203.0.113.0/121":   "public",
-					"::ffff:203.0.113.128/121": "private",
-				}),
-			},
-		},
-	}
-	for _, tc := range cases {
-		t.Run(tc.Description, func(t *testing.T) {
-			var got Configuration
-			decoder, err := mapstructure.NewDecoder(helpers.GetMapStructureDecoderConfig(&got))
-			if err != nil {
-				t.Fatalf("NewDecoder() error:\n%+v", err)
-			}
-			err = decoder.Decode(tc.Input)
-			if err != nil {
-				t.Fatalf("Decode() error:\n%+v", err)
-			} else if diff := helpers.Diff(got, tc.Output); diff != "" {
-				t.Fatalf("Decode() (-got, +want):\n%s", diff)
-			}
-		})
-	}
-}

inlet/snmp/root.go

@@ -285,7 +285,7 @@ func (c *Component) dispatchIncomingRequest(request lookupRequest) {
 func (c *Component) pollerIncomingRequest(request lookupRequest) {
 	community, ok := c.config.Communities.Lookup(net.ParseIP(request.ExporterIP))
 	if !ok {
-		community = "public"
+		community = c.config.DefaultCommunity
 	}
 
 	// Avoid querying too much exporters with errors

inlet/snmp/root_test.go

@@ -41,8 +41,8 @@ func TestLookup(t *testing.T) {
 func TestSNMPCommunities(t *testing.T) {
 	r := reporter.NewMock(t)
 	configuration := DefaultConfiguration()
-	configuration.Communities, _ = helpers.NewSubnetMap(map[string]string{
+	configuration.DefaultCommunity = "notpublic"
-		"::/0":                 "notpublic",
+	configuration.Communities = helpers.MustNewSubnetMap(map[string]string{
 		"::ffff:127.0.0.1/128": "public",
 		"::ffff:127.0.0.2/128": "private",
 	})