From 9a5d699f66b56f10576678f64aef9aa153685718 Mon Sep 17 00:00:00 2001
From: Andre Medeiros <me@andremedeiros.info>
Date: Sat, 14 Aug 2021 12:08:17 -0400
Subject: [PATCH] Remove stale devices

---
 internal/cmd/scheduler.go              | 27 ++++++++++++++++++++++++--
 internal/domain/device.go              |  2 ++
 internal/repository/postgres_device.go | 15 ++++++++++++++
 3 files changed, 42 insertions(+), 2 deletions(-)

diff --git a/internal/cmd/scheduler.go b/internal/cmd/scheduler.go
index 23c1d93..b42427e 100644
--- a/internal/cmd/scheduler.go
+++ b/internal/cmd/scheduler.go
@@ -23,6 +23,9 @@ const (
 	batchSize      = 250
 	checkTimeout   = 60 // how long until we force a check
 	enqueueTimeout = 5  // how long until we try to re-enqueue
+
+	staleAccountThreshold = 7200   // 2 hours
+	staleDeviceThreshold  = 604800 // 1 week
 )
 
 func SchedulerCmd(ctx context.Context) *cobra.Command {
@@ -72,6 +75,7 @@ func SchedulerCmd(ctx context.Context) *cobra.Command {
 			s.Every(1).Second().Do(func() { cleanQueues(ctx, logger, queue) })
 			s.Every(1).Minute().Do(func() { reportStats(ctx, logger, statsd, db, redis) })
 			s.Every(1).Minute().Do(func() { pruneAccounts(ctx, logger, db) })
+			s.Every(1).Minute().Do(func() { pruneDevices(ctx, logger, db) })
 			s.StartAsync()
 
 			<-ctx.Done()
@@ -105,10 +109,10 @@ func evalScript(ctx context.Context, redis *redis.Client) (string, error) {
 }
 
 func pruneAccounts(ctx context.Context, logger *logrus.Logger, pool *pgxpool.Pool) {
-	now := time.Now().Unix() - 7200
+	before := time.Now().Unix() - staleAccountThreshold
 	ar := repository.NewPostgresAccount(pool)
 
-	stale, err := ar.PruneStale(ctx, now)
+	stale, err := ar.PruneStale(ctx, before)
 	if err != nil {
 		logger.WithFields(logrus.Fields{
 			"err": err,
@@ -133,6 +137,25 @@ func pruneAccounts(ctx context.Context, logger *logrus.Logger, pool *pgxpool.Poo
 	}
 }
 
+func pruneDevices(ctx context.Context, logger *logrus.Logger, pool *pgxpool.Pool) {
+	before := time.Now().Unix() - staleDeviceThreshold
+	dr := repository.NewPostgresDevice(pool)
+
+	count, err := dr.PruneStale(ctx, before)
+	if err != nil {
+		logger.WithFields(logrus.Fields{
+			"err": err,
+		}).Error("failed cleaning stale devices")
+		return
+	}
+
+	if count > 0 {
+		logger.WithFields(logrus.Fields{
+			"count": count,
+		}).Info("pruned devices")
+	}
+}
+
 func cleanQueues(ctx context.Context, logger *logrus.Logger, jobsConn rmq.Connection) {
 	cleaner := rmq.NewCleaner(jobsConn)
 	count, err := cleaner.Clean()
diff --git a/internal/domain/device.go b/internal/domain/device.go
index cc2f4cd..40deeeb 100644
--- a/internal/domain/device.go
+++ b/internal/domain/device.go
@@ -15,4 +15,6 @@ type DeviceRepository interface {
 	Update(ctx context.Context, dev *Device) error
 	Create(ctx context.Context, dev *Device) error
 	Delete(ctx context.Context, token string) error
+
+	PruneStale(ctx context.Context, before int64) (int64, error)
 }
diff --git a/internal/repository/postgres_device.go b/internal/repository/postgres_device.go
index 5134a32..637023c 100644
--- a/internal/repository/postgres_device.go
+++ b/internal/repository/postgres_device.go
@@ -114,3 +114,18 @@ func (p *postgresDeviceRepository) Delete(ctx context.Context, token string) err
 	}
 	return err
 }
+
+func (p *postgresDeviceRepository) PruneStale(ctx context.Context, before int64) (int64, error) {
+	query := `
+		WITH deleted_devices AS (
+			DELETE FROM devices
+			WHERE last_pinged_at < $1
+			RETURNING id
+		)
+		DELETE FROM devices_accounts
+		WHERE device_id IN (SELECT id FROM deleted_devices)`
+
+	res, err := p.pool.Exec(ctx, query, before)
+
+	return res.RowsAffected(), err
+}