zero/telemetry: collect DAU and MAU

internal/zero/analytics/collector.go

@@ -0,0 +1,100 @@
+// 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"
+)
+
+const (
+	updateInterval = time.Second * 30
+)
+
+// Collect collects metrics and reports them to the cloud
+func Collect(
+	ctx context.Context,
+	client databroker.DataBrokerServiceClient,
+) error {
+	c := &collector{
+		client:   client,
+		counters: make(map[string]*ActiveUsersCounter),
+	}
+
+	now := time.Now()
+	for key, resetFn := range map[string]IntervalResetFunc{
+		"mau": ResetMonthlyUTC,
+		"dau": ResetDailyUTC,
+	} {
+		state, err := LoadMetricState(ctx, 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 c.run(ctx, updateInterval)
+}
+
+type collector struct {
+	client   databroker.DataBrokerServiceClient
+	counters map[string]*ActiveUsersCounter
+}
+
+func (c *collector) run(ctx context.Context, interval time.Duration) error {
+	ticker := time.NewTicker(interval)
+	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 {
+		updated := counter.Update(users, now)
+		if !updated {
+			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, counter.GetLastReset())
+		if err != nil {
+			return fmt.Errorf("failed to save metric %s: %w", key, err)
+		}
+	}
+
+	return nil
+}