zero/telemetry: calculate DAU and MAU (#4810)

internal/sets/hash.go

@@ -31,3 +31,12 @@ func (s *Hash[T]) Has(element T) bool {
 func (s *Hash[T]) Size() int {
 	return len(s.m)
 }
+
+// Items returns the set's elements as a slice.
+func (s *Hash[T]) Items() []T {
+	items := make([]T, 0, len(s.m))
+	for item := range s.m {
+		items = append(items, item)
+	}
+	return items
+}

internal/zero/analytics/activeusers.go

@@ -0,0 +1,80 @@
+package analytics
+
+import (
+	"time"
+
+	"github.com/pomerium/pomerium/pkg/counter"
+)
+
+const (
+	// activeUsersCap is the number of active users we would be able to track.
+	// for counter to work within the 1% error limit, actual number should be 80% of the cap.
+	activeUsersCap = 10_000
+)
+
+// IntervalResetFunc is a function that determines if a counter should be reset
+type IntervalResetFunc func(lastReset time.Time, now time.Time) bool
+
+// ResetMonthlyUTC resets the counter on a monthly interval
+func ResetMonthlyUTC(lastReset time.Time, now time.Time) bool {
+	lastResetUTC := lastReset.UTC()
+	nowUTC := now.UTC()
+	return lastResetUTC.Year() != nowUTC.Year() ||
+		lastResetUTC.Month() != nowUTC.Month()
+}
+
+// ResetDailyUTC resets the counter on a daily interval
+func ResetDailyUTC(lastReset time.Time, now time.Time) bool {
+	lastResetUTC := lastReset.UTC()
+	nowUTC := now.UTC()
+	return lastResetUTC.Year() != nowUTC.Year() ||
+		lastResetUTC.Month() != nowUTC.Month() ||
+		lastResetUTC.Day() != nowUTC.Day()
+}
+
+// ActiveUsersCounter is a counter that resets on a given interval
+type ActiveUsersCounter struct {
+	*counter.Counter
+	lastReset  time.Time
+	needsReset IntervalResetFunc
+}
+
+// NewActiveUsersCounter creates a new active users counter
+func NewActiveUsersCounter(needsReset IntervalResetFunc, now time.Time) *ActiveUsersCounter {
+	return &ActiveUsersCounter{
+		Counter:    counter.New(activeUsersCap),
+		lastReset:  now,
+		needsReset: needsReset,
+	}
+}
+
+// LoadActiveUsersCounter loads an active users counter from a binary state
+func LoadActiveUsersCounter(state []byte, lastReset time.Time, resetFn IntervalResetFunc) (*ActiveUsersCounter, error) {
+	c, err := counter.FromBinary(state)
+	if err != nil {
+		return nil, err
+	}
+	return &ActiveUsersCounter{
+		Counter:    c,
+		lastReset:  lastReset,
+		needsReset: resetFn,
+	}, nil
+}
+
+// Update updates the counter with the current users
+func (c *ActiveUsersCounter) Update(users []string, now time.Time) (current uint, wasReset bool) {
+	if c.needsReset(c.lastReset, now) {
+		c.Counter.Reset()
+		c.lastReset = now
+		wasReset = true
+	}
+	for _, user := range users {
+		c.Mark(user)
+	}
+	return c.Count(), wasReset
+}
+
+// GetLastReset returns the last time the counter was reset
+func (c *ActiveUsersCounter) GetLastReset() time.Time {
+	return c.lastReset
+}

internal/zero/analytics/activeusers_test.go

@@ -0,0 +1,37 @@
+package analytics_test
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/pomerium/pomerium/internal/zero/analytics"
+)
+
+func TestActiveUsers(t *testing.T) {
+	t.Parallel()
+
+	startTime := time.Now().UTC()
+
+	// Create a new counter that resets on a daily interval
+	c := analytics.NewActiveUsersCounter(analytics.ResetDailyUTC, startTime)
+
+	count, wasReset := c.Update([]string{"user1", "user2"}, startTime.Add(time.Minute))
+	assert.False(t, wasReset)
+	assert.EqualValues(t, 2, count)
+
+	count, wasReset = c.Update([]string{"user1", "user2", "user3"}, startTime.Add(time.Minute*2))
+	assert.False(t, wasReset)
+	assert.EqualValues(t, 3, count)
+
+	// Update the counter with a new user after lapse
+	count, wasReset = c.Update([]string{"user1", "user2", "user3", "user4"}, startTime.Add(time.Hour*25))
+	assert.True(t, wasReset)
+	assert.EqualValues(t, 4, count)
+
+	// Update the counter with a new user after lapse
+	count, wasReset = c.Update([]string{"user4"}, startTime.Add(time.Hour*25*2))
+	assert.True(t, wasReset)
+	assert.EqualValues(t, 1, count)
+}

internal/zero/analytics/collector.go

@@ -0,0 +1,131 @@
+// Package analytics collects active user metrics and reports them to the cloud dashboard
+package analytics
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/pomerium/pomerium/internal/log"
+	"github.com/pomerium/pomerium/pkg/grpc/databroker"
+)
+
+// Collect collects metrics and reports them to the cloud
+func Collect(
+	ctx context.Context,
+	client databroker.DataBrokerServiceClient,
+	updateInterval time.Duration,
+) error {
+	c := &collector{
+		client:         client,
+		counters:       make(map[string]*ActiveUsersCounter),
+		updateInterval: updateInterval,
+	}
+
+	leaser := databroker.NewLeaser("pomerium-zero-analytics", c.leaseTTL(), c)
+	return leaser.Run(ctx)
+}
+
+type collector struct {
+	client         databroker.DataBrokerServiceClient
+	counters       map[string]*ActiveUsersCounter
+	updateInterval time.Duration
+}
+
+func (c *collector) RunLeased(ctx context.Context) error {
+	err := c.loadCounters(ctx)
+	if err != nil {
+		return fmt.Errorf("failed to load counters: %w", err)
+	}
+
+	err = c.runPeriodicUpdate(ctx)
+	if err != nil {
+		return fmt.Errorf("failed to run periodic update: %w", err)
+	}
+
+	return nil
+}
+
+func (c *collector) GetDataBrokerServiceClient() databroker.DataBrokerServiceClient {
+	return c.client
+}
+
+func (c *collector) loadCounters(ctx context.Context) error {
+	now := time.Now()
+	for key, resetFn := range map[string]IntervalResetFunc{
+		"mau": ResetMonthlyUTC,
+		"dau": ResetDailyUTC,
+	} {
+		state, err := LoadMetricState(ctx, c.client, key)
+		if err != nil && !databroker.IsNotFound(err) {
+			return err
+		}
+		if state == nil {
+			c.counters[key] = NewActiveUsersCounter(resetFn, now)
+			continue
+		}
+
+		counter, err := LoadActiveUsersCounter(state.Data, state.LastReset, resetFn)
+		if err != nil {
+			log.Ctx(ctx).Error().Err(err).Str("metric", key).Msg("failed to load metric state, resetting")
+			counter = NewActiveUsersCounter(resetFn, now)
+		}
+		c.counters[key] = counter
+	}
+
+	return nil
+}
+
+func (c *collector) runPeriodicUpdate(ctx context.Context) error {
+	ticker := time.NewTicker(c.updateInterval)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-ctx.Done():
+			return nil
+		case <-ticker.C:
+			if err := c.update(ctx); err != nil {
+				return err
+			}
+		}
+	}
+}
+
+func (c *collector) update(ctx context.Context) error {
+	users, err := CurrentUsers(ctx, c.client)
+	if err != nil {
+		return fmt.Errorf("failed to get current users: %w", err)
+	}
+
+	now := time.Now()
+	for key, counter := range c.counters {
+		before := counter.Count()
+		after, _ := counter.Update(users, now)
+		if before == after {
+			log.Ctx(ctx).Debug().Msgf("metric %s not changed: %d", key, counter.Count())
+			continue
+		}
+		log.Ctx(ctx).Debug().Msgf("metric %s updated: %d", key, counter.Count())
+
+		data, err := counter.ToBinary()
+		if err != nil {
+			return fmt.Errorf("failed to marshal metric %s: %w", key, err)
+		}
+
+		err = SaveMetricState(ctx, c.client, key, data, after, counter.GetLastReset())
+		if err != nil {
+			return fmt.Errorf("failed to save metric %s: %w", key, err)
+		}
+	}
+
+	return nil
+}
+
+func (c *collector) leaseTTL() time.Duration {
+	const defaultTTL = time.Minute * 5
+	if defaultTTL < c.updateInterval {
+		return defaultTTL
+	}
+	return c.updateInterval
+}

internal/zero/analytics/sessions.go

@@ -0,0 +1,53 @@
+package analytics
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/pomerium/pomerium/internal/sets"
+	"github.com/pomerium/pomerium/pkg/grpc/databroker"
+	"github.com/pomerium/pomerium/pkg/grpc/session"
+	"github.com/pomerium/pomerium/pkg/protoutil"
+)
+
+var (
+	sessionTypeURL = protoutil.GetTypeURL(new(session.Session))
+)
+
+// CurrentUsers returns a list of users active within the current UTC day
+func CurrentUsers(
+	ctx context.Context,
+	client databroker.DataBrokerServiceClient,
+) ([]string, error) {
+	records, _, _, err := databroker.InitialSync(ctx, client, &databroker.SyncLatestRequest{
+		Type: sessionTypeURL,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("fetching sessions: %w", err)
+	}
+
+	users := sets.NewHash[string]()
+	utcNow := time.Now().UTC()
+	threshold := time.Date(utcNow.Year(), utcNow.Month(), utcNow.Day(), 0, 0, 0, 0, time.UTC)
+
+	for _, record := range records {
+		var s session.Session
+		err := record.GetData().UnmarshalTo(&s)
+		if err != nil {
+			return nil, fmt.Errorf("unmarshaling session: %w", err)
+		}
+		if s.UserId == "" { // session creation is in progress
+			continue
+		}
+		if s.AccessedAt == nil {
+			continue
+		}
+		if s.AccessedAt.AsTime().Before(threshold) {
+			continue
+		}
+		users.Add(s.UserId)
+	}
+
+	return users.Items(), nil
+}

internal/zero/analytics/storage.go

@@ -0,0 +1,126 @@
+package analytics
+
+import (
+	"context"
+	"encoding/base64"
+	"fmt"
+	"time"
+
+	"google.golang.org/protobuf/types/known/anypb"
+	"google.golang.org/protobuf/types/known/structpb"
+
+	"github.com/pomerium/pomerium/pkg/grpc/databroker"
+	"github.com/pomerium/pomerium/pkg/protoutil"
+)
+
+const (
+	metricStateTypeURL = "pomerium.io/ActiveUsersMetricState"
+)
+
+// SaveMetricState saves the state of a metric to the databroker
+func SaveMetricState(
+	ctx context.Context,
+	client databroker.DataBrokerServiceClient,
+	id string,
+	data []byte,
+	value uint,
+	lastReset time.Time,
+) error {
+	_, err := client.Put(ctx, &databroker.PutRequest{
+		Records: []*databroker.Record{{
+			Type: metricStateTypeURL,
+			Id:   id,
+			Data: (&MetricState{
+				Data:      data,
+				LastReset: lastReset,
+				Count:     value,
+			}).ToAny(),
+		}},
+	})
+	return err
+}
+
+// LoadMetricState loads the state of a metric from the databroker
+func LoadMetricState(
+	ctx context.Context, client databroker.DataBrokerServiceClient, id string,
+) (*MetricState, error) {
+	resp, err := client.Get(ctx, &databroker.GetRequest{
+		Type: metricStateTypeURL,
+		Id:   id,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("load metric state: %w", err)
+	}
+
+	var state MetricState
+	err = state.FromAny(resp.GetRecord().GetData())
+	if err != nil {
+		return nil, fmt.Errorf("load metric state: %w", err)
+	}
+
+	return &state, nil
+}
+
+// MetricState is the persistent state of a metric
+type MetricState struct {
+	Data      []byte
+	LastReset time.Time
+	Count     uint
+}
+
+const (
+	countKey     = "count"
+	dataKey      = "data"
+	lastResetKey = "last_reset"
+)
+
+// ToAny marshals a MetricState into an anypb.Any
+func (r *MetricState) ToAny() *anypb.Any {
+	return protoutil.NewAny(&structpb.Struct{
+		Fields: map[string]*structpb.Value{
+			countKey:     structpb.NewNumberValue(float64(r.Count)),
+			dataKey:      structpb.NewStringValue(base64.StdEncoding.EncodeToString(r.Data)),
+			lastResetKey: structpb.NewStringValue(r.LastReset.Format(time.RFC3339)),
+		},
+	})
+}
+
+// FromAny unmarshals an anypb.Any into a MetricState
+func (r *MetricState) FromAny(any *anypb.Any) error {
+	var s structpb.Struct
+	err := any.UnmarshalTo(&s)
+	if err != nil {
+		return fmt.Errorf("unmarshal struct: %w", err)
+	}
+
+	vData, ok := s.GetFields()[dataKey]
+	if !ok {
+		return fmt.Errorf("missing %s field", dataKey)
+	}
+	data, err := base64.StdEncoding.DecodeString(vData.GetStringValue())
+	if err != nil {
+		return fmt.Errorf("decode state: %w", err)
+	}
+	if len(data) == 0 {
+		return fmt.Errorf("empty data")
+	}
+
+	vLastReset, ok := s.GetFields()[lastResetKey]
+	if !ok {
+		return fmt.Errorf("missing %s field", lastResetKey)
+	}
+	lastReset, err := time.Parse(time.RFC3339, vLastReset.GetStringValue())
+	if err != nil {
+		return fmt.Errorf("parse last reset: %w", err)
+	}
+	vCount, ok := s.GetFields()[countKey]
+	if !ok {
+		return fmt.Errorf("missing %s field", countKey)
+	}
+
+	r.Data = data
+	r.LastReset = lastReset
+	r.Count = uint(vCount.GetNumberValue())
+
+	return nil
+}

internal/zero/analytics/storage_test.go

@@ -0,0 +1,29 @@
+package analytics_test
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/pomerium/pomerium/internal/zero/analytics"
+)
+
+func TestStorage(t *testing.T) {
+	t.Parallel()
+
+	now := time.Date(2020, 1, 2, 3, 4, 5, 6, time.UTC)
+	state := &analytics.MetricState{
+		Data:      []byte("data"),
+		LastReset: now,
+	}
+
+	pbany := state.ToAny()
+	assert.NotNil(t, pbany)
+
+	var newState analytics.MetricState
+	err := newState.FromAny(pbany)
+	assert.NoError(t, err)
+	assert.EqualValues(t, state.Data, newState.Data)
+	assert.EqualValues(t, state.LastReset.Truncate(time.Second), newState.LastReset.Truncate(time.Second))
+}

internal/zero/controller/controller.go

@@ -5,11 +5,13 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"time"
 
 	"github.com/rs/zerolog"
 	"golang.org/x/sync/errgroup"
 
 	"github.com/pomerium/pomerium/internal/log"
+	"github.com/pomerium/pomerium/internal/zero/analytics"
 	"github.com/pomerium/pomerium/internal/zero/bootstrap"
 	"github.com/pomerium/pomerium/internal/zero/reconciler"
 	"github.com/pomerium/pomerium/pkg/cmd/pomerium"
@@ -43,6 +45,7 @@ func Run(ctx context.Context, opts ...Option) error {
 	eg.Go(func() error { return run(ctx, "pomerium-core", c.runPomeriumCore, src.WaitReady) })
 	eg.Go(func() error { return run(ctx, "zero-reconciler", c.runReconciler, src.WaitReady) })
 	eg.Go(func() error { return run(ctx, "connect-log", c.RunConnectLog, nil) })
+	eg.Go(func() error { return run(ctx, "zero-analytics", c.runAnalytics, src.WaitReady) })
 	return eg.Wait()
 }
 
@@ -117,3 +120,13 @@ func (c *controller) runReconciler(ctx context.Context) error {
 		reconciler.WithDataBrokerClient(c.GetDataBrokerServiceClient()),
 	)
 }
+
+func (c *controller) runAnalytics(ctx context.Context) error {
+	err := analytics.Collect(ctx, c.GetDataBrokerServiceClient(), time.Second*30)
+	if err != nil && ctx.Err() == nil {
+		log.Ctx(ctx).Error().Err(err).Msg("error collecting analytics, disabling")
+		return nil
+	}
+
+	return err
+}

pkg/grpc/databroker/databroker.go

@@ -8,6 +8,8 @@ import (
 	"fmt"
 	"io"
 
+	"google.golang.org/grpc/codes"
+	status "google.golang.org/grpc/status"
 	"google.golang.org/protobuf/encoding/protojson"
 	"google.golang.org/protobuf/proto"
 	structpb "google.golang.org/protobuf/types/known/structpb"
@@ -33,6 +35,11 @@ func NewRecord(object recordObject) *Record {
 	}
 }
 
+// IsNotFound returns true if the error is a not found error.
+func IsNotFound(err error) bool {
+	return status.Code(err) == codes.NotFound
+}
+
 // Get gets a record from the databroker and unmarshals it into the object.
 func Get(ctx context.Context, client DataBrokerServiceClient, object recordObject) error {
 	res, err := client.Get(ctx, &GetRequest{