[CNS] add config snapshot event metrics at an interval (#3140)

* feat: add and expose new ConfigSnapshotIntervalInMins config

* feat: add interval event emitting of CNS config snapshot

* lint: address lint errors

* chore: send CNS config snapshot immediately

* test: refactor test to be less coupled

* lint

* fix: remove setting default ConfigSnapshotIntervalInMins

* chore: remove unnecessary comment

cns/configuration/cns_config.json

@@ -5,6 +5,7 @@
         "HeartBeatIntervalInMins": 30,
         "RefreshIntervalInSecs": 15,
         "SnapshotIntervalInMins": 60,
+        "ConfigSnapshotIntervalInMins": 60,
         "TelemetryBatchIntervalInSecs": 15,
         "TelemetryBatchSizeBytes": 16384
     },

cns/configuration/configuration.go

@@ -80,6 +80,8 @@ type TelemetrySettings struct {
 	DebugMode bool
 	// Interval for sending snapshot events.
 	SnapshotIntervalInMins int
+	// Interval for sending config snapshot events.
+	ConfigSnapshotIntervalInMins int
 	// AppInsightsInstrumentationKey allows the user to override the default appinsights ikey
 	AppInsightsInstrumentationKey string
 }

cns/configuration/configuration_test.go

@@ -80,6 +80,7 @@ func TestReadConfigFromFile(t *testing.T) {
 					HeartBeatIntervalInMins:      30,
 					RefreshIntervalInSecs:        15,
 					SnapshotIntervalInMins:       60,
+					ConfigSnapshotIntervalInMins: 60,
 					TelemetryBatchIntervalInSecs: 15,
 					TelemetryBatchSizeBytes:      16384,
 				},

cns/configuration/testdata/good.json

@@ -26,6 +26,7 @@
         "HeartBeatIntervalInMins": 30,
         "RefreshIntervalInSecs": 15,
         "SnapshotIntervalInMins": 60,
+        "ConfigSnapshotIntervalInMins": 60,
         "TelemetryBatchIntervalInSecs": 15,
         "TelemetryBatchSizeBytes": 16384
     },

cns/logger/constants.go

@@ -3,17 +3,20 @@ package logger
 
 const (
 	// Metrics
-	HeartBeatMetricStr = "HeartBeat"
+	HeartBeatMetricStr       = "HeartBeat"
+	ConfigSnapshotMetricsStr = "ConfigSnapshot"
 
 	// Dimensions
-	OrchestratorTypeStr = "OrchestratorType"
-	NodeIDStr           = "NodeID"
-	HomeAZStr           = "HomeAZ"
-	IsAZRSupportedStr   = "IsAZRSupported"
-	HomeAZErrorCodeStr  = "HomeAZErrorCode"
-	HomeAZErrorMsgStr   = "HomeAZErrorMsg"
+	OrchestratorTypeStr             = "OrchestratorType"
+	NodeIDStr                       = "NodeID"
+	HomeAZStr                       = "HomeAZ"
+	IsAZRSupportedStr               = "IsAZRSupported"
+	HomeAZErrorCodeStr              = "HomeAZErrorCode"
+	HomeAZErrorMsgStr               = "HomeAZErrorMsg"
+	CNSConfigPropertyStr            = "CNSConfiguration"
+	CNSConfigMD5CheckSumPropertyStr = "CNSConfigurationMD5Checksum"
 
-	// CNS Snspshot properties
+	// CNS NC Snspshot properties
 	CnsNCSnapshotEventStr         = "CNSNCSnapshot"
 	IpConfigurationStr            = "IPConfiguration"
 	LocalIPConfigurationStr       = "LocalIPConfiguration"

cns/metric/configsnapshot.go

@@ -0,0 +1,58 @@
+package metric
+
+import (
+	"context"
+	"crypto/md5" //nolint:gosec // used for checksum
+	"encoding/json"
+	"time"
+
+	"github.com/Azure/azure-container-networking/aitelemetry"
+	"github.com/Azure/azure-container-networking/cns/configuration"
+	"github.com/Azure/azure-container-networking/cns/logger"
+	"github.com/pkg/errors"
+)
+
+// SendCNSConfigSnapshot emits CNS config periodically
+func SendCNSConfigSnapshot(ctx context.Context, config *configuration.CNSConfig) {
+	ticker := time.NewTicker(time.Minute * time.Duration(config.TelemetrySettings.ConfigSnapshotIntervalInMins))
+	defer ticker.Stop()
+
+	event, err := createCNSConfigSnapshotEvent(config)
+	if err != nil {
+		logger.Errorf("[Azure CNS] SendCNSConfigSnapshot: %v", err)
+		return
+	}
+
+	// Log the first event immediately
+	logger.LogEvent(event)
+
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-ticker.C:
+			logger.LogEvent(event)
+		}
+	}
+}
+
+func createCNSConfigSnapshotEvent(config *configuration.CNSConfig) (aitelemetry.Event, error) {
+	bb, err := json.Marshal(config) //nolint:musttag // no tag needed for config
+	if err != nil {
+		return aitelemetry.Event{}, errors.Wrap(err, "failed to marshal config")
+	}
+
+	cs := md5.Sum(bb) //nolint:gosec // used for checksum
+	csStr := string(cs[:])
+
+	event := aitelemetry.Event{
+		EventName:  logger.ConfigSnapshotMetricsStr,
+		ResourceID: csStr, // not guaranteed unique, instead use VM ID and Subscription to correlate
+		Properties: map[string]string{
+			logger.CNSConfigPropertyStr:            string(bb),
+			logger.CNSConfigMD5CheckSumPropertyStr: csStr,
+		},
+	}
+
+	return event, nil
+}

cns/metric/configsnapshot_test.go

@@ -0,0 +1,30 @@
+package metric
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/Azure/azure-container-networking/cns/configuration"
+	"github.com/Azure/azure-container-networking/cns/logger"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestCreateCNSConfigSnapshotEvent(t *testing.T) {
+	logger.InitLogger("testlogs", 0, 0, "./")
+
+	config, err := configuration.ReadConfig("../configuration/testdata/good.json")
+	require.NoError(t, err)
+
+	event, err := createCNSConfigSnapshotEvent(config)
+	require.NoError(t, err)
+
+	assert.Equal(t, logger.ConfigSnapshotMetricsStr, event.EventName)
+	assert.NotEmpty(t, event.ResourceID)
+	assert.Contains(t, event.Properties[logger.CNSConfigPropertyStr], "\"TLSPort\":\"10091\"")
+
+	eventConfig := &configuration.CNSConfig{}
+	err = json.Unmarshal([]byte(event.Properties[logger.CNSConfigPropertyStr]), eventConfig) //nolint:musttag // no tag needed for config
+	require.NoError(t, err)
+	assert.EqualValues(t, config, eventConfig)
+}

cns/service/main.go

@@ -578,6 +578,10 @@ func main() {
 		} else {
 			logger.InitAI(aiConfig, ts.DisableTrace, ts.DisableMetric, ts.DisableEvent)
 		}
+
+		if cnsconfig.TelemetrySettings.ConfigSnapshotIntervalInMins > 0 {
+			go metric.SendCNSConfigSnapshot(rootCtx, cnsconfig)
+		}
 	}
 	logger.Printf("[Azure CNS] Using config: %+v", cnsconfig)