MINOR: stats: also support a "no-maint" show stat modifier

"no-maint" is a bit similar to "up" except that it will only hide
servers that are in maintenance (or disabled in the configuration), and
not those that are enabled but failed a check. One benefit here is to
significantly reduce the output of the "show stat" command when using
large server-templates containing entries that are not yet provisioned.

Note that the prometheus exporter also has such an option which does
the exact same.
diff --git a/doc/management.txt b/doc/management.txt
index 2411405..ca6cfc2 100644
--- a/doc/management.txt
+++ b/doc/management.txt
@@ -2123,7 +2123,7 @@
   that the output format may evolve over time so this output must not be parsed
   by tools designed to be durable.
 
-show info [typed|json] [desc] [up]
+show info [typed|json] [desc] [up|no-maint]
   Dump info about haproxy status on current process. If "typed" is passed as an
   optional argument, field numbers, names and types are emitted as well so that
   external monitoring products can easily retrieve, possibly aggregate, then
@@ -2138,7 +2138,10 @@
 
   The "up" modifier will result in listing only servers which reportedly up or
   not checked. Those down, unresolved, or in maintenance will not be listed.
-  This is analogous to the ";up" option on the HTTP stats.
+  This is analogous to the ";up" option on the HTTP stats. Similarly, the
+  "no-maint" modifier will act like the ";no-maint" HTTP modifier and will
+  result in disabled servers not to be listed. The difference is that those
+  which are enabled but down will not be evicted.
 
   When using the typed output format, each line is made of 4 columns delimited
   by colons (':'). The first column is a dot-delimited series of 3 elements. The
diff --git a/include/haproxy/stats-t.h b/include/haproxy/stats-t.h
index b9e255c..8b69a0b 100644
--- a/include/haproxy/stats-t.h
+++ b/include/haproxy/stats-t.h
@@ -40,6 +40,7 @@
 #define STAT_SHLGNDS    0x00000800      /* conf: show legends */
 #define STAT_SHOW_FDESC 0x00001000      /* show the field descriptions when possible */
 #define STAT_SHMODULES  0x00002000      /* conf: show modules */
+#define STAT_HIDE_MAINT 0x00004000	/* hide maint/disabled servers */
 
 #define STAT_BOUND      0x00800000	/* bound statistics to selected proxies/types/services */
 #define STAT_STARTED    0x01000000	/* some output has occurred */
diff --git a/src/http_ana.c b/src/http_ana.c
index 1dd43dc..f2edc68 100644
--- a/src/http_ana.c
+++ b/src/http_ana.c
@@ -4086,6 +4086,10 @@
 			appctx->ctx.stats.flags |= STAT_HIDE_DOWN;
 			break;
 		}
+		if (memcmp(h, ";no-maint", 3) == 0) {
+			appctx->ctx.stats.flags |= STAT_HIDE_MAINT;
+			break;
+		}
 	}
 
 	if (uri_auth->refresh) {
diff --git a/src/stats.c b/src/stats.c
index f6417b9..fe02765 100644
--- a/src/stats.c
+++ b/src/stats.c
@@ -2565,6 +2565,12 @@
 					continue;
 			}
 
+			/* do not report disabled servers */
+			if (appctx->ctx.stats.flags & STAT_HIDE_MAINT &&
+			    sv->cur_admin & SRV_ADMF_MAINT) {
+				continue;
+			}
+
 			svs = sv;
 			while (svs->track)
 				svs = svs->track;
@@ -4310,6 +4316,8 @@
 			appctx->ctx.stats.flags = (appctx->ctx.stats.flags & ~STAT_FMT_MASK) | STAT_FMT_JSON;
 		else if (strcmp(args[arg], "desc") == 0)
 			appctx->ctx.stats.flags |= STAT_SHOW_FDESC;
+		else if (strcmp(args[arg], "no-maint") == 0)
+			appctx->ctx.stats.flags |= STAT_HIDE_MAINT;
 		else if (strcmp(args[arg], "up") == 0)
 			appctx->ctx.stats.flags |= STAT_HIDE_DOWN;
 		arg++;
@@ -4504,7 +4512,7 @@
 static struct cli_kw_list cli_kws = {{ },{
 	{ { "clear", "counters",  NULL }, "clear counters : clear max statistics counters (add 'all' for all counters)", cli_parse_clear_counters, NULL, NULL },
 	{ { "show", "info",  NULL }, "show info      : report information about the running process [desc|json|typed]*", cli_parse_show_info, cli_io_handler_dump_info, NULL },
-	{ { "show", "stat",  NULL }, "show stat      : report counters for each proxy and server [desc|json|typed|up]*", cli_parse_show_stat, cli_io_handler_dump_stat, NULL },
+	{ { "show", "stat",  NULL }, "show stat      : report counters for each proxy and server [desc|json|no-maint|typed|up]*", cli_parse_show_stat, cli_io_handler_dump_stat, NULL },
 	{ { "show", "schema",  "json", NULL }, "show schema json : report schema used for stats", NULL, cli_io_handler_dump_json_schema, NULL },
 	{{},}
 }};