From: Michael Tremer <michael.tremer@ipfire.org>
Date: Wed, 22 Oct 2025 19:26:42 +0000 (+0000)
Subject: source: Don't try to commit metrics too soon
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d210a205745e9cdbca41875f50d4249ac31cbb0d;p=telemetry.git

source: Don't try to commit metrics too soon

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
---

diff --git a/src/daemon/source.c b/src/daemon/source.c
index 0099251..002aa49 100644
--- a/src/daemon/source.c
+++ b/src/daemon/source.c
@@ -907,12 +907,45 @@ static int td_source_fetch_lastupdate(td_source* self, rrd_info_t* info, time_t*
 	return 0;
 }
 
+static int td_source_serialize_metrics(td_source* self, char*** samples,
+		unsigned int num_metrics, td_metrics** metrics, time_t lastupdate) {
+	const struct timeval* t = NULL;
+	char sample[4096];
+	int r;
+
+	for (unsigned int i = 0; i < num_metrics; i++) {
+		// Fetch the time of the metric
+		t = td_metrics_get_time(metrics[i]);
+
+		// RRD throws an error if we try to write more than one sample per second.
+		// Therefore, we will throw away all metrics that have been collected too soon.
+		if (lastupdate && t->tv_sec <= lastupdate) {
+			DEBUG(self->ctx, "Throwing away metric for %s which has been collected too soon\n",
+				td_source_name(self));
+			continue;
+		}
+
+		// Serialize the metrics
+		r = td_metrics_serialize(metrics[i], sample);
+		if (r < 0)
+			return r;
+
+		// Append it to the array
+		r = td_strings_append(samples, sample);
+		if (r < 0)
+			return r;
+	}
+
+	return 0;
+}
+
 /*
-	Called to write all collected samples to disk
+	Called to write all collected metrics to disk
 */
-static int td_source_commit_samples(td_source* self,
-		const char* object, unsigned int num_samples, const char** samples) {
+int td_source_commit_metrics(td_source* self, const char* object,
+		unsigned int num_metrics, td_metrics** metrics) {
 	rrd_info_t* info = NULL;
+	char** samples = NULL;
 	time_t lastupdate = 0;
 	char path[PATH_MAX];
 	int r;
@@ -951,45 +984,26 @@ static int td_source_commit_samples(td_source* self,
 			goto ERROR;
 	}
 
-	// Write the samples
-	r = rrd_update_r(path, NULL, num_samples, samples);
-	if (r < 0) {
-		ERROR(self->ctx, "Failed to write to %s: %s\n", path, rrd_get_error());
-		rrd_clear_error();
-		return -EFAULT;
-	}
-
-ERROR:
-	if (info)
-		rrd_info_free(info);
-
-	return r;
-}
-
-int td_source_commit_metrics(td_source* self, const char* object,
-		unsigned int num_metrics, td_metrics** metrics) {
-	char** samples = NULL;
-	char sample[4096];
-	int r;
-
-	for (unsigned int i = 0; i < num_metrics; i++) {
-		// Serialize the metrics
-		r = td_metrics_serialize(metrics[i], sample);
-		if (r < 0)
-			goto ERROR;
+	// Serialize the samples
+	r = td_source_serialize_metrics(self, &samples, num_metrics, metrics, lastupdate);
+	if (r < 0)
+		goto ERROR;
 
-		// Append it to the array
-		r = td_strings_append(&samples, sample);
-		if (r < 0)
-			goto ERROR;
+	// Write the samples
+	if (samples) {
+		r = rrd_update_r(path, NULL, td_strings_length(samples), (const char**)samples);
+		if (r < 0) {
+			ERROR(self->ctx, "Failed to write to %s: %s\n", path, rrd_get_error());
+			rrd_clear_error();
+			return -EFAULT;
+		}
 	}
 
-	// Commit the samples
-	r = td_source_commit_samples(self, object, num_metrics, (const char**)samples);
-
 ERROR:
 	if (samples)
 		td_strings_free(samples);
+	if (info)
+		rrd_info_free(info);
 
 	return r;
 }