Implement ometric_set_timeval() and ometric_set_timeval_with_labels()

Timestamps are special since they can require more significant bits
than a double provides. Instead print them as pseudo float as suggested
by the OpenMetrics draft.
OK cheloha@

3 files changed, 47 insertions, 8 deletions

diff --git a/usr.sbin/bgpctl/ometric.c b/usr.sbin/bgpctl/ometric.c
index 296c08026d3..c7fd626ee53 100644
--- a/usr.sbin/bgpctl/ometric.c
+++ b/usr.sbin/bgpctl/ometric.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ometric.c,v 1.5 2022/12/05 11:50:11 claudio Exp $ */
+/*	$OpenBSD: ometric.c,v 1.6 2022/12/06 11:27:58 claudio Exp $ */
 
 /*
  * Copyright (c) 2022 Claudio Jeker <claudio@openbsd.org>
@@ -17,6 +17,7 @@
  */
 
 #include <sys/queue.h>
+#include <sys/time.h>
 
 #include <err.h>
 #include <stdarg.h>
@@ -42,6 +43,7 @@ struct olabels {
 enum ovalue_type {
 	OVT_INTEGER,
 	OVT_DOUBLE,
+	OVT_TIMEVAL,
 };
 
 struct ovalue {
@@ -50,6 +52,7 @@ struct ovalue {
 	union {
 		unsigned long long	i;
 		double			f;
+		struct timeval		tv;
 	}			 value;
 	enum ovalue_type	 valtype;
 };
@@ -274,6 +277,9 @@ ometric_output_value(FILE *out, const struct ovalue *ov)
 		return fprintf(out, "%llu", ov->value.i);
 	case OVT_DOUBLE:
 		return fprintf(out, "%g", ov->value.f);
+	case OVT_TIMEVAL:
+		return fprintf(out, "%lld.%06ld",
+		    (long long)ov->value.tv.tv_sec, (long)ov->value.tv.tv_usec);
 	}
 	return -1;
 }
@@ -366,6 +372,28 @@ ometric_set_float(struct ometric *om, double val, struct olabels *ol)
 }
 
 /*
+ * Set an timeval value with label ol. ol can be NULL.
+ */
+void
+ometric_set_timeval(struct ometric *om, const struct timeval *tv,
+    struct olabels *ol)
+{
+	struct ovalue *ov;
+
+	if (om->type != OMT_GAUGE)
+		errx(1, "%s incorrect ometric type", __func__);
+
+	if ((ov = malloc(sizeof(*ov))) == NULL)
+		err(1, NULL);
+
+	ov->value.tv = *tv;
+	ov->valtype = OVT_TIMEVAL;
+	ov->labels = olabels_ref(ol);
+
+	STAILQ_INSERT_TAIL(&om->vals, ov, entry);
+}
+
+/*
  * Add an info value (which is the value 1 but with extra key-value pairs).
  */
 void
@@ -424,3 +452,14 @@ ometric_set_int_with_labels(struct ometric *om, uint64_t val,
 	ometric_set_int(om, val, extra);
 	olabels_free(extra);
 }
+
+void
+ometric_set_timeval_with_labels(struct ometric *om, struct timeval *tv,
+    const char **keys, const char **values, struct olabels *ol)
+{
+	struct olabels *extra;
+
+	extra = olabels_add_extras(ol, keys, values);
+	ometric_set_timeval(om, tv, extra);
+	olabels_free(extra);
+}
diff --git a/usr.sbin/bgpctl/ometric.h b/usr.sbin/bgpctl/ometric.h
index bd90f2d8b3d..0e66857bd85 100644
--- a/usr.sbin/bgpctl/ometric.h
+++ b/usr.sbin/bgpctl/ometric.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ometric.h,v 1.3 2022/12/01 09:14:40 claudio Exp $ */
+/*	$OpenBSD: ometric.h,v 1.4 2022/12/06 11:27:58 claudio Exp $ */
 
 /*
  * Copyright (c) 2022 Claudio Jeker <claudio@openbsd.org>
@@ -41,9 +41,13 @@ int		 ometric_output_all(FILE *);
 /* functions to set gauge and counter metrics */
 void	ometric_set_int(struct ometric *, uint64_t, struct olabels *);
 void	ometric_set_float(struct ometric *, double, struct olabels *);
+void	ometric_set_timeval(struct ometric *, const struct timeval *,
+	    struct olabels *);
 void	ometric_set_info(struct ometric *, const char **, const char **,
 	    struct olabels *); 
 void	ometric_set_state(struct ometric *, const char *, struct olabels *); 
 void	ometric_set_int_with_labels(struct ometric *, uint64_t, const char **,
 	    const char **, struct olabels *);
+void	ometric_set_timeval_with_labels(struct ometric *, struct timeval *,
+	    const char **, const char **, struct olabels *);
 #define OKV(...)		(const char *[]){ __VA_ARGS__, NULL }
diff --git a/usr.sbin/bgpctl/output_ometric.c b/usr.sbin/bgpctl/output_ometric.c
index ba016f1f788..b9572a0bf80 100644
--- a/usr.sbin/bgpctl/output_ometric.c
+++ b/usr.sbin/bgpctl/output_ometric.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: output_ometric.c,v 1.6 2022/12/01 09:16:43 claudio Exp $ */
+/*	$OpenBSD: output_ometric.c,v 1.7 2022/12/06 11:27:58 claudio Exp $ */
 
 /*
  * Copyright (c) 2022 Claudio Jeker <claudio@openbsd.org>
@@ -319,15 +319,11 @@ static void
 ometric_tail(void)
 {
 	struct timeval elapsed_time;
-	double scrape;
 
 	gettimeofday(&end_time, NULL);
 	timersub(&end_time, &start_time, &elapsed_time);
 
-	scrape = (double)elapsed_time.tv_sec +
-	    (double)elapsed_time.tv_usec / 1000000;
-
-	ometric_set_float(bgpd_scrape_time, scrape, NULL);
+	ometric_set_timeval(bgpd_scrape_time, &elapsed_time, NULL);
 	ometric_output_all(stdout);
 
 	ometric_free_all();