1 files changed, 51 insertions, 0 deletions
diff --git a/pkgs/servers/monitoring/prometheus/smartctl-exporter/0001-Return-the-cached-value-if-it-s-not-time-to-scan-aga.patch b/pkgs/servers/monitoring/prometheus/smartctl-exporter/0001-Return-the-cached-value-if-it-s-not-time-to-scan-aga.patch
new file mode 100644
index 00000000000..28616251f37
--- /dev/null
+++ b/pkgs/servers/monitoring/prometheus/smartctl-exporter/0001-Return-the-cached-value-if-it-s-not-time-to-scan-aga.patch
@@ -0,0 +1,51 @@
+From e81b06df67b1d42ef915615fafa0b56ef956673b Mon Sep 17 00:00:00 2001
+From: Andreas Fuchs <asf@boinkor.net>
+Date: Thu, 11 Feb 2021 17:30:44 -0500
+Subject: [PATCH] Return the cached value if it's not time to scan again yet
+
+This should ensure that if we have a valid value cached (which ought
+to be every time after the first scan), we return it as metrics.
+
+This fixes the crashes that would happen if queries happened earlier
+than the re-scan interval allowed.
+
+Address review feedback: Shorten the time-to-scan logic
+
+We can express this in a single if statement, so it takes fewer lines
+to do the "should we check again" check.
+---
+ readjson.go | 11 ++---------
+ 1 file changed, 2 insertions(+), 9 deletions(-)
+
+diff --git a/readjson.go b/readjson.go
+index da35448..c9996fd 100644
+--- a/readjson.go
++++ b/readjson.go
+@@ -78,14 +78,7 @@ func readData(device string) (gjson.Result, error) {
+ 
+ 	if _, err := os.Stat(device); err == nil {
+ 		cacheValue, cacheOk := jsonCache[device]
+-		timeToScan := false
+-		if cacheOk {
+-			timeToScan = time.Now().After(cacheValue.LastCollect.Add(options.SMARTctl.CollectPeriodDuration))
+-		} else {
+-			timeToScan = true
+-		}
+-
+-		if timeToScan {
++		if !cacheOk || time.Now().After(cacheValue.LastCollect.Add(options.SMARTctl.CollectPeriodDuration)) {
+ 			json, ok := readSMARTctl(device)
+ 			if ok {
+ 				jsonCache[device] = JSONCache{JSON: json, LastCollect: time.Now()}
+@@ -93,7 +86,7 @@ func readData(device string) (gjson.Result, error) {
+ 			}
+ 			return gjson.Parse(DEFAULT_EMPTY_JSON), fmt.Errorf("smartctl returned bad data for device %s", device)
+ 		}
+-		return gjson.Parse(DEFAULT_EMPTY_JSON), fmt.Errorf("Too early collect called for device %s", device)
++		return cacheValue.JSON, nil
+ 	}
+ 	return gjson.Parse(DEFAULT_EMPTY_JSON), fmt.Errorf("Device %s unavialable", device)
+ }
+-- 
+2.33.1
+