From 85b157570bd43fc5e92214a9da3d2b876686be33 Mon Sep 17 00:00:00 2001
From: Willy Tarreau <w@1wt.eu>
Date: Mon, 12 Aug 2019 16:44:33 +0200
Subject: [PATCH] MINOR: trace/cli: add "show trace" to report trace state and
 statistics

The new "show trace" CLI command lists available trace sources and
indicates their status, their sink, and number of dropped packets.
When "show trace <source>" is used, the list of known events is
also listed with their status per action (report/start/stop/pause).
---
 src/trace.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/src/trace.c b/src/trace.c
index 6d40fec63..8691b65f1 100644
--- a/src/trace.c
+++ b/src/trace.c
@@ -239,8 +239,63 @@ static int cli_parse_trace(char **args, char *payload, struct appctx *appctx, vo
 	return 0;
 }
 
+/* parse the command, returns 1 if a message is returned, otherwise zero */
+static int cli_parse_show_trace(char **args, char *payload, struct appctx *appctx, void *private)
+{
+	struct trace_source *src;
+	const struct sink *sink;
+	int i;
+
+	args++; // make args[1] the 1st arg
+
+	if (!*args[1]) {
+		/* no arg => report the list of supported sources */
+		chunk_printf(&trash,
+			     "Supported trace sources and states (.=stopped, w=waiting, R=running) :\n"
+			     );
+
+		list_for_each_entry(src, &trace_sources, source_link) {
+			sink = src->sink;
+			chunk_appendf(&trash, " [%c] %-10s -> %s [drp %u]  [%s]\n",
+				      trace_state_char(src->state), src->name.ptr,
+				      sink ? sink->name : "none",
+				      sink ? sink->ctx.dropped : 0,
+				      src->desc);
+		}
+
+		trash.area[trash.data] = 0;
+		return cli_msg(appctx, LOG_INFO, trash.area);
+	}
+
+	if (!cli_has_level(appctx, ACCESS_LVL_OPER))
+		return 1;
+
+	src = trace_find_source(args[1]);
+	if (!src)
+		return cli_err(appctx, "No such trace source");
+
+	sink = src->sink;
+	chunk_printf(&trash, "Trace status for %s:\n", src->name.ptr);
+	chunk_appendf(&trash, "  - sink: %s [%u dropped]\n",
+		      sink ? sink->name : "none", sink ? sink->ctx.dropped : 0);
+
+	chunk_appendf(&trash, "  - event name :     report    start    stop    pause\n");
+	for (i = 0; src->known_events && src->known_events[i].mask; i++) {
+		chunk_appendf(&trash, "    %-10s :        %c        %c        %c       %c\n",
+			      src->known_events[i].name,
+			      trace_event_char(src->report_events, src->known_events[i].mask),
+			      trace_event_char(src->start_events, src->known_events[i].mask),
+			      trace_event_char(src->stop_events, src->known_events[i].mask),
+			      trace_event_char(src->pause_events, src->known_events[i].mask));
+	}
+
+	trash.area[trash.data] = 0;
+	return cli_msg(appctx, LOG_WARNING, trash.area);
+}
+
 static struct cli_kw_list cli_kws = {{ },{
 	{ { "trace", NULL }, "trace <module> [cmd [args...]] : manage live tracing", cli_parse_trace, NULL, NULL },
+	{ { "show", "trace", NULL }, "show trace [<module>] : show live tracing state", cli_parse_show_trace, NULL, NULL },
 	{{},}
 }};