Introduce out_trigger module

out_trigger runs a trigger when a probe exceeds above or drops below a
given threshold

src/Makefile.am

@@ -41,4 +41,5 @@ bmon_SOURCES = \
 	out_null.c \
 	out_format.c \
 	out_ascii.c \
-	out_curses.c
+	out_curses.c \
+	out_trigger.c

src/out_trigger.c

@@ -0,0 +1,197 @@
+/*
+ * out_trigger.c		Trigger based on traffic pattern
+ *
+ * Copyright (c) 2018 Babak Farrokhi <babak@farrokhi.net>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include <bmon/bmon.h>
+#include <bmon/graph.h>
+#include <bmon/conf.h>
+#include <bmon/output.h>
+#include <bmon/group.h>
+#include <bmon/element.h>
+#include <bmon/input.h>
+#include <bmon/utils.h>
+#include <bmon/attr.h>
+
+#define RECENT_SIZE 3
+
+static int c_quit_after_trigger = 0;
+static long c_threshold_high = -1;
+static long c_threshold_low = -1;
+static unsigned long recent_l[RECENT_SIZE];
+static unsigned long recent_count = 0;
+static unsigned long recent_avg = 0;
+static unsigned long triggered = 0;
+static char *c_format;
+static FILE *c_fd;
+
+static char *get_token(struct element_group *g, struct element *e,
+		       const char *token, char *buf, size_t len)
+{
+	char *name = strchr(token, ':');
+
+	struct attr_def *def;
+	struct attr *a;
+
+	if (!name)
+		quit("Invalid attribute field \"%s\"\n", token);
+
+	name++;
+
+	def = attr_def_lookup(name);
+	if (!def)
+		quit("Undefined attribute \"%s\"\n", name);
+
+	if (!(a = attr_lookup(e, def->ad_id)))
+		quit("Invalid attribute \"%s\"\n", name);
+
+	if (!strncasecmp(token, "rxrate:", 7)) {
+		snprintf(buf, len, "%.2f", a->a_rx_rate.r_rate);
+		return buf;
+	} else if (!strncasecmp(token, "txrate:", 7)) {
+		snprintf(buf, len, "%.2f", a->a_tx_rate.r_rate);
+		return buf;
+	}
+
+	quit("Unknown field \"%s\"\n", token);
+
+	return NULL;
+}
+
+static void run_trigger()
+{
+	// TODO: Run the command
+	if (++triggered >= c_quit_after_trigger)
+		exit(0);
+}
+
+static void trigger_check()
+{
+	if (recent_count < RECENT_SIZE)
+		return;
+
+	if (c_threshold_high > 0 && recent_avg > c_threshold_high) {
+		fprintf(c_fd, "TRIGGER: Passed high threshold: %li > %li\n", recent_avg, c_threshold_high);
+		run_trigger();
+		return;
+	}
+	if (c_threshold_low > 0 && recent_avg < c_threshold_low) {
+		fprintf(c_fd, "TRIGGER: Droppped below threshold: %li < %li\n", recent_avg, c_threshold_low);
+		run_trigger();
+		return;
+	}
+}
+
+static void trigger_process(struct element_group *g, struct element *e, void *arg)
+{
+	char buf[128];
+	char *p;
+
+	p = get_token(g, e, c_format, buf, sizeof(buf));
+
+	if (p)
+	{
+		int i;
+		unsigned long total = 0;
+
+		recent_l[recent_count % RECENT_SIZE] = strtol(p, NULL, 0);
+		for (i=0; i < RECENT_SIZE; i++)
+		{
+			fprintf(c_fd, "%li ", recent_l[i]);
+			total += recent_l[i];
+		}
+
+		recent_avg = (unsigned long) total / RECENT_SIZE;
+		fprintf(c_fd, " avg: %li\n", recent_avg);
+		trigger_check();
+		recent_count++;
+	}
+}
+
+static void trigger_do(void)
+{
+	group_foreach_recursive(trigger_process, NULL);
+	fflush(stdout);
+}
+
+static void print_help(void)
+{
+	printf(
+	"trigger - Run actions based on traffic patterns\n" \
+	"\n" \
+	"  Monitors a given probe and triggers an action if the criteria is met.\n" \
+	"  Criterias could be going above or dropping below a given threshold of traffic.\n" \
+	"  Probes could be Bytes/sec or Packets/sec on TX or RX\n" \
+	"\n" \
+	"\n" \
+	"  Author: Babak Farrokhi <babak@farrokhi.net>\n" \
+	"\n" \
+	"  Options:\n" \
+	"    probe=ELEMENT     Element to monitor for threshold\n" \
+	"    action=PROGRAM    Program or script to run when triggered\n" \
+	"    below=THRESHOLD   Minimum acceptable level for given element (average in past three seconds)\n" \
+	"    above=THRESHOLD   Maximum acceptable level for given element (average in past three seconds)\n" \
+	"    quittriggers=NUM  Quit after NUM triggers\n" \
+	"\n" \
+	"  Probe Elements:\n" \
+	"    rxrate:packets    RX packet rate\n" \
+	"    txrate:packets    TX packet rate\n" \
+	"    rxrate:bytes      RX traffic rate (bytes)\n" \
+	"    txrate:bytes      TX traffic rate (bytes)\n" \
+	"\n" \
+	"  Examples:\n" \
+	"    bmon -p eth0 -o 'trigger:probe=rxrate:packets;below=5000;quittriggers=3;action=/opt/bin/alert'\n" \
+	"\n");
+}
+
+static void trigger_parse_opt(const char *type, const char *value)
+{
+	if (!strcasecmp(type, "above") && value)
+		c_threshold_high = strtol(value, NULL, 0);
+	else if (!strcasecmp(type, "below") && value)
+		c_threshold_low = strtol(value, NULL, 0);
+	else if (!strcasecmp(type, "quittriggers") && value)
+		c_quit_after_trigger = strtol(value, NULL, 0);
+	else if (!strcasecmp(type, "probe")) {
+		if (c_format)
+			free(c_format);
+		c_format = strdup(value);
+	}
+	else if (!strcasecmp(type, "help")) {
+		print_help();
+		exit(0);
+	}
+}
+
+static struct bmon_module trigger_ops = {
+	.m_name		= "trigger",
+	.m_do		= trigger_do,
+	.m_parse_opt	= trigger_parse_opt,
+};
+
+static void __init ascii_init(void)
+{
+	c_fd = stdout;
+	c_format = strdup("$(rxrate:packets)\\n");
+
+	output_register(&trigger_ops);
+}