From d65bab79703461cc6ebbc42d0fab53e170d4a975 Mon Sep 17 00:00:00 2001
From: Andre Medeiros <me@andremedeiros.info>
Date: Thu, 8 Jul 2021 22:09:14 -0400
Subject: [PATCH] rejig sql

---
 cmd/apollo-scheduler/main.go | 44 ++++++++++++++++++++++++++++--------
 1 file changed, 35 insertions(+), 9 deletions(-)

diff --git a/cmd/apollo-scheduler/main.go b/cmd/apollo-scheduler/main.go
index cc9e424..25f1e58 100644
--- a/cmd/apollo-scheduler/main.go
+++ b/cmd/apollo-scheduler/main.go
@@ -9,6 +9,7 @@ import (
 	"syscall"
 	"time"
 
+	"github.com/DataDog/datadog-go/statsd"
 	"github.com/adjust/rmq/v4"
 	"github.com/go-co-op/gocron"
 	"github.com/go-redis/redis/v8"
@@ -39,6 +40,13 @@ func main() {
 		}
 	}
 
+	statsd, err := statsd.New("127.0.0.1:8125")
+	if err != nil {
+		logger.WithFields(logrus.Fields{
+			"err": err,
+		}).Error("failed to set up stats")
+	}
+
 	// Set up Postgres connection
 	var pool *pgxpool.Pool
 	{
@@ -89,7 +97,7 @@ func main() {
 	}
 
 	s := gocron.NewScheduler(time.UTC)
-	s.Every(1).Second().Do(func() { enqueueAccounts(ctx, logger, pool, redisConn, notificationsQueue) })
+	s.Every(1).Second().Do(func() { enqueueAccounts(ctx, logger, statsd, pool, redisConn, notificationsQueue) })
 	s.StartAsync()
 
 	signals := make(chan os.Signal, 1)
@@ -106,11 +114,16 @@ func main() {
 	s.Stop()
 }
 
-func enqueueAccounts(ctx context.Context, logger *logrus.Logger, pool *pgxpool.Pool, redisConn *redis.Client, queue rmq.Queue) {
+func enqueueAccounts(ctx context.Context, logger *logrus.Logger, statsd *statsd.Client, pool *pgxpool.Pool, redisConn *redis.Client, queue rmq.Queue) {
 	now := float64(time.Now().UnixNano()/int64(time.Millisecond)) / 1000
 
-	start := time.Now().Unix()
+	// Start looking for accounts that were last checked at least 5 seconds ago
+	// and at most 6 seconds ago. Also look for accounts that haven't been checked
+	// in over a minute.
+	ts := time.Now().Unix()
+	start := ts - 6
 	end := start + 1
+	expired := ts - 60
 
 	ids := []int64{}
 
@@ -120,15 +133,15 @@ func enqueueAccounts(ctx context.Context, logger *logrus.Logger, pool *pgxpool.P
 			  SELECT id
 				FROM accounts
 				WHERE
-					(last_checked_at + 5) BETWEEN $1 and $2
-					OR last_checked_at + 60 <= $1
+					last_checked_at BETWEEN $1 AND $2
+					OR last_checked_at < $3
 				ORDER BY last_checked_at
 			)
 			UPDATE accounts
-			SET last_enqueued_at = $3
+			SET last_enqueued_at = $4
 			WHERE accounts.id IN(SELECT id FROM account)
 			RETURNING accounts.id`
-		rows, err := tx.Query(ctx, stmt, start, end, now)
+		rows, err := tx.Query(ctx, stmt, start, end, expired, now)
 		if err != nil {
 			return err
 		}
@@ -156,6 +169,7 @@ func enqueueAccounts(ctx context.Context, logger *logrus.Logger, pool *pgxpool.P
 
 	enqueued := 0
 	skipped := 0
+	failed := 0
 	for _, id := range ids {
 		payload := fmt.Sprintf("%d", id)
 		lockKey := fmt.Sprintf("locks:accounts:%s", payload)
@@ -178,13 +192,25 @@ func enqueueAccounts(ctx context.Context, logger *logrus.Logger, pool *pgxpool.P
 			}).Error("failed to lock account")
 		}
 
-		enqueued++
-		_ = queue.Publish(payload)
+		if err = queue.Publish(payload); err != nil {
+			logger.WithFields(logrus.Fields{
+				"accountID": payload,
+				"err":       err,
+			}).Error("failed to enqueue account")
+			failed++
+		} else {
+			enqueued++
+		}
 	}
 
+	statsd.Histogram("apollo.queue.enqueued", float64(enqueued), []string{}, 1)
+	statsd.Histogram("apollo.queue.skipped", float64(skipped), []string{}, 1)
+	statsd.Histogram("apollo.queue.failed", float64(failed), []string{}, 1)
+
 	logger.WithFields(logrus.Fields{
 		"count":   enqueued,
 		"skipped": skipped,
+		"failed":  failed,
 		"start":   start,
 		"end":     end,
 	}).Info("done enqueueing account batch")