From 6e46469592f587c71379f26e561f07c89b25cee3 Mon Sep 17 00:00:00 2001
From: JasonPowr <japower@redhat.com>
Date: Wed, 20 Nov 2024 15:01:00 +0000
Subject: [PATCH] set-up-index-tracking-for-backfill-index

Signed-off-by: JasonPowr <japower@redhat.com>
---
 cmd/backfill-index/main.go | 63 ++++++++++++++++++++++++++++++++++++--
 1 file changed, 61 insertions(+), 2 deletions(-)

diff --git a/cmd/backfill-index/main.go b/cmd/backfill-index/main.go
index 6169b2a57..9db656d06 100644
--- a/cmd/backfill-index/main.go
+++ b/cmd/backfill-index/main.go
@@ -38,6 +38,7 @@ import (
 	"log"
 	"os"
 	"os/signal"
+	"strconv"
 	"strings"
 	"syscall"
 	"time"
@@ -90,6 +91,10 @@ const (
 	providerMySQL
 )
 
+const (
+	redisLastProcessedIndexKey = "last_processed_index"
+)
+
 type indexClient interface {
 	idempotentAddToIndex(ctx context.Context, key, value string) error
 }
@@ -127,6 +132,7 @@ var (
 	redisPassword           = flag.String("redis-password", "", "Password for Redis authentication")
 	redisEnableTLS          = flag.Bool("redis-enable-tls", false, "Enable TLS for Redis client")
 	redisInsecureSkipVerify = flag.Bool("redis-insecure-skip-verify", false, "Whether to skip TLS verification for Redis client or not")
+	enableRedisIndexResume  = flag.Bool("enable-redis-index-resume", false, "Enable resuming from the last processed index stored in Redis. When enabled, the '--start' flag becomes optional for the Redis provider.")
 	mysqlDSN                = flag.String("mysql-dsn", "", "MySQL Data Source Name")
 	startIndex              = flag.Int("start", -1, "First index to backfill")
 	endIndex                = flag.Int("end", -1, "Last index to backfill")
@@ -158,7 +164,7 @@ func main() {
 	if *mysqlDSN != "" {
 		provider = providerMySQL
 	}
-	if *redisHostname != "" || *redisPort != "" || *redisPassword != "" {
+	if *redisHostname != "" || *redisPort != "" || *redisPassword != "" || enableRedisIndexResume != nil {
 		provider = providerRedis
 	}
 	if provider == providerUnset {
@@ -172,7 +178,10 @@ func main() {
 			log.Fatal("Redis port must be set")
 		}
 	}
-	if *startIndex == -1 {
+	if *enableRedisIndexResume && *startIndex != -1 {
+		log.Fatal("--enable-redis-index-resume and --start cannot be set simultaneously")
+	}
+	if *startIndex == -1 && !*enableRedisIndexResume {
 		log.Fatal("start must be set to >=0")
 	}
 	if *endIndex == -1 {
@@ -276,6 +285,24 @@ func populate(indexClient indexClient, rekorClient *rekorclient.Rekor) (err erro
 		}
 	}()
 
+	var lastFilled int
+	if *enableRedisIndexResume && !*dryRun {
+		redisClient, ok := indexClient.(*redisClient)
+		if !ok {
+			log.Fatal("enableRedisIndexResume is only supported with Redis backend")
+		}
+		lastFilled, err = redisClient.getLastFilledIndex(ctx)
+		if err != nil {
+			log.Fatalf("Failed to retrieve last filled index: %v", err)
+		}
+		if lastFilled == -1 {
+			log.Printf("%s not found, starting from index 0", redisLastProcessedIndexKey)
+			*startIndex = 0
+		} else {
+			*startIndex = lastFilled + 1 // Start from the next index
+		}
+	}
+
 	for i := *startIndex; i <= *endIndex; i++ {
 		index := i // capture loop variable for closure
 		group.Go(func() error {
@@ -345,6 +372,19 @@ func populate(indexClient indexClient, rekorClient *rekorclient.Rekor) (err erro
 			return nil
 		})
 	}
+
+	if *enableRedisIndexResume && !*dryRun {
+		redisClient, ok := indexClient.(*redisClient)
+		if !ok {
+			log.Fatal("enableRedisIndexResume is only supported with Redis backend")
+		}
+		if err := redisClient.setLastFilledIndex(ctx, *endIndex); err != nil {
+			log.Printf("Failed to set last filled index: %v", err)
+		} else {
+			fmt.Printf("Last filled index updated to %d\n", *endIndex)
+		}
+	}
+
 	err = group.Wait()
 	if err != nil {
 		return fmt.Errorf("error running backfill: %v", err)
@@ -393,3 +433,22 @@ func (c *mysqlClient) idempotentAddToIndex(ctx context.Context, key, value strin
 	_, err := c.client.NamedExecContext(ctx, mysqlWriteStmt, map[string]any{"key": key, "uuid": value})
 	return err
 }
+
+func (c *redisClient) getLastFilledIndex(ctx context.Context) (int, error) {
+	val, err := c.client.Get(ctx, redisLastProcessedIndexKey).Result()
+	if err != nil {
+		if err == redis.Nil {
+			return -1, nil // No index has been filled yet
+		}
+		return 0, fmt.Errorf("failed to get last filled index from Redis: %w", err)
+	}
+	index, err := strconv.Atoi(val)
+	if err != nil {
+		return 0, fmt.Errorf("invalid last filled index value in Redis: %w", err)
+	}
+	return index, nil
+}
+
+func (c *redisClient) setLastFilledIndex(ctx context.Context, index int) error {
+	return c.client.Set(ctx, redisLastProcessedIndexKey, index, 0).Err()
+}