From be1a39b03b00575d2eedcbd501d09b925029397d Mon Sep 17 00:00:00 2001
From: Steffen Vogel <post@steffenvogel.de>
Date: Wed, 28 Mar 2018 14:13:13 +0200
Subject: [PATCH] hook: added new hook for rate limiting
---
lib/hooks/Makefile.inc | 2 +-
lib/hooks/limit_rate.c | 140 +++++++++++++++++++++++++++
tests/integration/hook-limit_rate.sh | 41 ++++++++
3 files changed, 182 insertions(+), 1 deletion(-)
create mode 100644 lib/hooks/limit_rate.c
create mode 100755 tests/integration/hook-limit_rate.sh
diff --git a/lib/hooks/Makefile.inc b/lib/hooks/Makefile.inc
index b81ac2a4a..586dd592e 100644
--- a/lib/hooks/Makefile.inc
+++ b/lib/hooks/Makefile.inc
@@ -22,7 +22,7 @@
LIB_SRCS += $(addprefix lib/hooks/, convert.c decimate.c drop.c jitter_calc.c \
map.c restart.c shift_seq.c shift_ts.c \
- skip_first.c stats.c ts.c)
+ skip_first.c stats.c ts.c limit_rate.c)
ifeq ($(WITH_IO),1)
LIB_SRCS += lib/hooks/print.c
diff --git a/lib/hooks/limit_rate.c b/lib/hooks/limit_rate.c
new file mode 100644
index 000000000..04e1f9f24
--- /dev/null
+++ b/lib/hooks/limit_rate.c
@@ -0,0 +1,140 @@
+/** Rate-limiting hook.
+ *
+ * @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
+ * @copyright 2017, Institute for Automation of Complex Power Systems, EONERC
+ * @license GNU General Public License (version 3)
+ *
+ * VILLASnode
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *********************************************************************************/
+
+/** @addtogroup hooks Hook functions
+ * @{
+ */
+
+#include <string.h>
+
+#include "villas/hook.h"
+#include "villas/plugin.h"
+#include "villas/timing.h"
+#include "villas/sample.h"
+
+struct limit_rate {
+ enum {
+ LIMIT_RATE_LOCAL,
+ LIMIT_RATE_RECEIVED,
+ LIMIT_RATE_ORIGIN
+ } mode; /**< The timestamp which should be used for limiting. */
+
+ double deadtime;
+ struct timespec last;
+};
+
+static int limit_rate_init(struct hook *h)
+{
+ struct limit_rate *p = (struct limit_rate *) h->_vd;
+
+ p->last = (struct timespec) { 0 };
+
+ /* Default values */
+ p->mode = LIMIT_RATE_LOCAL;
+
+ return 0;
+}
+
+static int limit_rate_parse(struct hook *h, json_t *cfg)
+{
+ struct limit_rate *p = (struct limit_rate *) h->_vd;
+
+ int ret;
+ json_error_t err;
+
+ double rate;
+ const char *mode = NULL;
+
+ ret = json_unpack_ex(cfg, &err, 0, "{ s: F, s?: s }",
+ "rate", &rate,
+ "mode", &mode
+ );
+ if (ret)
+ jerror(&err, "Failed to parse configuration of hook '%s'", plugin_name(h->_vt));
+
+ if (mode) {
+ if (!strcmp(mode, "origin"))
+ p->mode = LIMIT_RATE_ORIGIN;
+ else if (!strcmp(mode, "received"))
+ p->mode = LIMIT_RATE_RECEIVED;
+ else if (!strcmp(mode, "local"))
+ p->mode = LIMIT_RATE_LOCAL;
+ else
+ error("Invalid value '%s' for setting 'mode' in limit_rate hook", mode);
+ }
+
+ p->deadtime = 1.0 / rate;
+
+ return 0;
+}
+
+static int limit_rate_write(struct hook *h, struct sample *smps[], unsigned *cnt)
+{
+ struct limit_rate *p = (struct limit_rate *) h->_vd;
+
+ struct timespec next;
+ unsigned ret = 0;
+
+ for (unsigned i = 0; i < *cnt; i++) {
+ switch (p->mode) {
+ case LIMIT_RATE_LOCAL:
+ next = time_now();
+ break;
+
+ case LIMIT_RATE_ORIGIN:
+ next = smps[i]->ts.origin;
+ break;
+
+ case LIMIT_RATE_RECEIVED:
+ next = smps[i]->ts.received;
+ break;
+ }
+
+ if (time_delta(&p->last, &next) < p->deadtime)
+ continue; /* Drop this sample */
+
+ p->last = next;
+ smps[ret++] = smps[i];
+ }
+
+ *cnt = ret;
+
+ return 0;
+}
+
+static struct plugin p = {
+ .name = "limit_rate",
+ .description = "Limit sending rate",
+ .type = PLUGIN_TYPE_HOOK,
+ .hook = {
+ .flags = HOOK_NODE | HOOK_PATH,
+ .priority = 99,
+ .init = limit_rate_init,
+ .parse = limit_rate_parse,
+ .write = limit_rate_write,
+ .size = sizeof(struct limit_rate)
+ }
+};
+
+REGISTER_PLUGIN(&p)
+
+/** @} */
diff --git a/tests/integration/hook-limit_rate.sh b/tests/integration/hook-limit_rate.sh
new file mode 100755
index 000000000..11e42e3a7
--- /dev/null
+++ b/tests/integration/hook-limit_rate.sh
@@ -0,0 +1,41 @@
+#!/bin/bash
+#
+# Integration test for limit_rate hook.
+#
+# @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
+# @copyright 2018 Institute for Automation of Complex Power Systems, EONERC
+# @license GNU General Public License (version 3)
+#
+# VILLASnode
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+##################################################################################
+
+INPUT_FILE=$(mktemp)
+OUTPUT_FILE=$(mktemp)
+EXPECT_FILE=$(mktemp)
+
+villas-signal sine -r 1000 -l 1000 -n > ${INPUT_FILE}
+awk 'NR % 10 == 2' < ${INPUT_FILE} > ${EXPECT_FILE}
+
+villas-hook limit_rate -o rate=100 -o mode=origin < ${INPUT_FILE} > ${OUTPUT_FILE}
+
+# Compare only the data values
+villas-test-cmp ${OUTPUT_FILE} ${EXPECT_FILE}
+
+RC=$?
+
+rm -f ${INPUT_FILE} ${OUTPUT_FILE} ${EXPECT_FILE}
+
+exit $RC