MINOR: promex: introduce haproxy_backend_agg_check_status

This patch introduces haproxy_backend_agg_check_status metric
as we wanted in 42d7c402d but with the right data source.

This patch could be backported as far as 2.4.

(cherry picked from commit e06e31ea3b62ef8ccb911ac3969ae70f7bbb7574)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit f0319e0f56581873f906f79dc218bf6f10b8f6c2)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit d8567a9fea61ae0ab0019a7cc563961e7afc34ad)
[cf: Adapted because the appctx was refactored in 2.6]
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit 67cd53b415f2f411dfebe2024d0b480e740be258)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
diff --git a/src/stats.c b/src/stats.c
index 8fcc42c..f46ce2f 100644
--- a/src/stats.c
+++ b/src/stats.c
@@ -259,6 +259,7 @@
 	[ST_F_UWEIGHT]                       = { .name = "uweight",                     .desc = "Server's user weight, or sum of active servers' user weights for a backend" },
 	[ST_F_AGG_SRV_CHECK_STATUS]          = { .name = "agg_server_check_status",     .desc = "Backend's aggregated gauge of servers' state check status" },
 	[ST_F_AGG_SRV_STATUS ]               = { .name = "agg_server_status",           .desc = "Backend's aggregated gauge of servers' status" },
+	[ST_F_AGG_CHECK_STATUS]              = { .name = "agg_check_status",            .desc = "Backend's aggregated gauge of servers' state check status" },
 };
 
 /* one line of info */
@@ -2671,6 +2672,9 @@
 			case ST_F_AGG_SRV_STATUS:
 				metric = mkf_u32(FN_GAUGE, 0);
 				break;
+			case ST_F_AGG_CHECK_STATUS:
+				metric = mkf_u32(FN_GAUGE, 0);
+				break;
 			case ST_F_WEIGHT:
 				metric = mkf_u32(FN_AVG, (px->lbprm.tot_weight * px->lbprm.wmult + px->lbprm.wdiv - 1) / px->lbprm.wdiv);
 				break;