From: Michael Tremer <michael.tremer@ipfire.org>
Date: Fri, 5 Jun 2026 15:32:53 +0000 (+0000)
Subject: source: Check if we have data for a source without going to disk
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7d0128d4fcf80db86888c6f9d42a7c39e10503ef;p=telemetry.git

source: Check if we have data for a source without going to disk

We will only check if the RRD is available if we really need to.

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

diff --git a/src/daemon/daemon.c b/src/daemon/daemon.c
index 283608f..b45ae9e 100644
--- a/src/daemon/daemon.c
+++ b/src/daemon/daemon.c
@@ -511,8 +511,11 @@ int td_daemon_submit_metrics(td_daemon* self, td_metrics* metrics) {
 	return td_queue_submit_metrics(self->queue, metrics);
 }
 
-int td_daemon_flush_source(
-		td_daemon* self, td_source* source, const char* object) {
+int td_daemon_has_source(td_daemon* self, td_source* source, const char* object) {
+	return td_queue_has_source(self->queue, source, object);
+}
+
+int td_daemon_flush_source(td_daemon* self, td_source* source, const char* object) {
 	return td_queue_flush_source(self->queue, source, object);
 }
 
diff --git a/src/daemon/daemon.h b/src/daemon/daemon.h
index 35857fb..f99b7e6 100644
--- a/src/daemon/daemon.h
+++ b/src/daemon/daemon.h
@@ -53,8 +53,8 @@ int td_daemon_exit(td_daemon* self, int rc);
 
 int td_daemon_submit_metrics(td_daemon* self, td_metrics* metrics);
 
-int td_daemon_flush_source(
-	td_daemon* self, td_source* source, const char* object);
+int td_daemon_has_source(td_daemon* self, td_source* source, const char* object);
+int td_daemon_flush_source(td_daemon* self, td_source* source, const char* object);
 
 #ifdef HAVE_LIBNL3
 td_netlink* td_daemon_get_netlink(td_daemon* self);
diff --git a/src/daemon/queue.c b/src/daemon/queue.c
index 32fd99f..945e45f 100644
--- a/src/daemon/queue.c
+++ b/src/daemon/queue.c
@@ -363,6 +363,26 @@ int td_queue_flush(td_queue* self) {
 	return 0;
 }
 
+int td_queue_has_source(td_queue* self,td_source* source, const char* object) {
+	struct td_queue_object* o = NULL;
+
+	STAILQ_FOREACH(o, &self->queue, nodes) {
+		// Continue if the source does not match
+		if (o->source != source)
+			continue;
+
+		// Continue if the object does not match
+		if (!td_queue_object_equals(self, o, object))
+			continue;
+
+		// Match
+		return 1;
+	}
+
+	// No match
+	return 0;
+}
+
 int td_queue_flush_source(td_queue* self,
 		td_source* source, const char* object) {
 	struct td_queue_object* o = NULL;
diff --git a/src/daemon/queue.h b/src/daemon/queue.h
index 0a51842..97506e5 100644
--- a/src/daemon/queue.h
+++ b/src/daemon/queue.h
@@ -38,6 +38,8 @@ int td_queue_submit_metrics(td_queue* self, td_metrics* metrics);
 
 int td_queue_flush(td_queue* self);
 
+int td_queue_has_source(td_queue* self,td_source* source, const char* object);
+
 int td_queue_flush_source(td_queue* self,
 	td_source* source, const char* object);
 
diff --git a/src/daemon/source.c b/src/daemon/source.c
index c089943..6382d50 100644
--- a/src/daemon/source.c
+++ b/src/daemon/source.c
@@ -1218,15 +1218,21 @@ int td_source_render(td_source* self, td_args* args, const char* object) {
 	if (r < 0)
 		return r;
 
-	// Commit any buffered data right now
-	r = td_daemon_flush_source(self->daemon, self, object);
-	if (r < 0)
-		return r;
+	// Check if we have this object
+	r = td_source_has_object(self, object);
+	switch (r) {
+		// Not found
+		case 0:
+			return -ENOENT;
+
+		// Found
+		case 1:
+			break;
 
-	// Fail if the path does not exist
-	r = access(path, R_OK);
-	if (r < 0)
-		return -errno;
+		// Raise any other errors
+		default:
+			return r;
+	}
 
 	// Add all data sources
 	for (const td_rrd_ds* ds = self->impl->rrd_dss; ds->field; ds++) {
@@ -1235,5 +1241,38 @@ int td_source_render(td_source* self, td_args* args, const char* object) {
 			return r;
 	}
 
-	return 0;
+	// Commit any buffered data right now
+	return td_daemon_flush_source(self->daemon, self, object);
+}
+
+int td_source_has_object(td_source* self, const char* object) {
+	char path[PATH_MAX];
+	int r;
+
+	// Fast path by checking if there is anything in the queue
+	r = td_daemon_has_source(self->daemon, self, object);
+	if (r)
+		return r;
+
+	// Determine the path to the RRD file
+	r = td_source_path(self, object, path);
+	if (r < 0)
+		return r;
+
+	// Fail if the path does not exist
+	r = access(path, R_OK);
+	if (r < 0) {
+		switch (errno) {
+			// Object has not been found
+			case ENOENT:
+				return 0;
+
+			// Error
+			default:
+				return -errno;
+		}
+	}
+
+	// Object has been found
+	return 1;
 }
diff --git a/src/daemon/source.h b/src/daemon/source.h
index 446545e..67b2b2a 100644
--- a/src/daemon/source.h
+++ b/src/daemon/source.h
@@ -119,4 +119,6 @@ int td_source_commit_metrics(td_source* self, const char* object,
 int td_source_render(td_source* self,
 	td_args* args, const char* object);
 
+int td_source_has_object(td_source* self, const char* object);
+
 #endif /* TELEMETRY_SOURCE_H */