From 7c292905a833ad03fc63c38d12311d60706bef8b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C5=81ukasz=20Magiera?= <magik6k@gmail.com>
Date: Thu, 18 Apr 2024 12:56:22 +0200
Subject: [PATCH] curio: Make sector index GC work

---
 curiosrc/gc/storage_endpoint_gc.go        | 24 +++++++++++++++--------
 lib/harmony/harmonytask/singleton_task.go |  2 +-
 2 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/curiosrc/gc/storage_endpoint_gc.go b/curiosrc/gc/storage_endpoint_gc.go
index 1dd26ee03..191945773 100644
--- a/curiosrc/gc/storage_endpoint_gc.go
+++ b/curiosrc/gc/storage_endpoint_gc.go
@@ -2,7 +2,6 @@ package gc
 
 import (
 	"context"
-	"os"
 	"strings"
 	"sync"
 	"time"
@@ -149,13 +148,27 @@ func (s *StorageEndpointGC) Do(taskID harmonytask.TaskID, stillOwned func() bool
 				lastDeadReason = pingResult.res.Error.Error()
 			}
 
+			// This function updates the liveness data for a URL in the `sector_path_url_liveness` table.
+			//
+			// On conflict, where the same `storage_id` and `url` are found:
+			// - last_checked is always updated to the current timestamp.
+			// - last_live is updated to the new `last_live` if it is not null; otherwise, it retains the existing value.
+			// - last_dead is conditionally updated based on two criteria:
+			//   1. It is set to the new `last_dead` if the existing `last_dead` is null (indicating this is the first recorded failure).
+			//   2. It is updated to the new `last_dead` if there has been a live instance recorded after the most recent dead timestamp, indicating the resource was alive again before this new failure.
+			//   3. It retains the existing value if none of the above conditions are met.
+			// - last_dead_reason is updated similarly to `last_live`, using COALESCE to prefer the new reason if it's provided.
 			_, err := tx.Exec(`
 					INSERT INTO sector_path_url_liveness (storage_id, url, last_checked, last_live, last_dead, last_dead_reason)
 					VALUES ($1, $2, $3, $4, $5, $6)
 					ON CONFLICT (storage_id, url) DO UPDATE
 					SET last_checked = EXCLUDED.last_checked,
 						last_live = COALESCE(EXCLUDED.last_live, sector_path_url_liveness.last_live),
-						last_dead = COALESCE(EXCLUDED.last_dead, sector_path_url_liveness.last_dead),
+						last_dead = CASE
+							WHEN sector_path_url_liveness.last_dead IS NULL THEN EXCLUDED.last_dead
+							WHEN sector_path_url_liveness.last_dead IS NOT NULL AND sector_path_url_liveness.last_live > sector_path_url_liveness.last_dead THEN EXCLUDED.last_dead
+							ELSE sector_path_url_liveness.last_dead
+						END,
 						last_dead_reason = COALESCE(EXCLUDED.last_dead_reason, sector_path_url_liveness.last_dead_reason)
 				`, pingResult.storageID, pingResult.url, currentTime, lastLive, lastDead, lastDeadReason)
 			if err != nil {
@@ -186,7 +199,7 @@ func (s *StorageEndpointGC) Do(taskID harmonytask.TaskID, stillOwned func() bool
 		}
 		err = tx.Select(&deadURLs, `
 			SELECT storage_id, url FROM sector_path_url_liveness
-			WHERE last_dead > last_live AND last_dead < $1
+			WHERE last_dead > COALESCE(last_live, '1970-01-01') AND last_dead < $1
 		`, currentTime.Add(-StorageEndpointDeadTime).UTC())
 		if err != nil {
 			return false, xerrors.Errorf("selecting dead URLs: %w", err)
@@ -211,11 +224,6 @@ func (s *StorageEndpointGC) Do(taskID harmonytask.TaskID, stillOwned func() bool
 
 			log.Debugw("filtered urls", "urls", urls, "dead_url", du.URL, "storage_id", du.StorageID)
 
-			if os.Getenv("CURIO_STORAGE_META_GC_DRYRUN") != "no" { // todo drop this after testing
-				log.Debugw("dryrun: not updating storage path", "storage_id", du.StorageID, "urls", urls, "dead_url", du.URL, "current_urls", URLs, "dead_urls", deadURLs)
-				continue
-			}
-
 			if len(urls) == 0 {
 				// If no URLs left, remove the storage path entirely
 				_, err = tx.Exec("DELETE FROM storage_path WHERE storage_id = $1", du.StorageID)
diff --git a/lib/harmony/harmonytask/singleton_task.go b/lib/harmony/harmonytask/singleton_task.go
index a7b2d45a2..720033410 100644
--- a/lib/harmony/harmonytask/singleton_task.go
+++ b/lib/harmony/harmonytask/singleton_task.go
@@ -26,7 +26,7 @@ func SingletonTaskAdder(minInterval time.Duration, task TaskInterface) func(AddT
 				}
 			}
 
-			now := time.Now()
+			now := time.Now().UTC()
 			// Determine if the task should run based on the absence of a record or outdated last_run_time
 			shouldRun := err == pgx.ErrNoRows || (existingTaskID == nil && lastRunTime.Add(minInterval).Before(now))
 			if !shouldRun {