Add /metrics endpoint which outputs stats in openmetrics format.

This uses `bgpctl show metric` to produce the payload.
OK tb@

diff --git a/usr.sbin/bgplgd/bgplgd.c b/usr.sbin/bgplgd/bgplgd.c
index 12d993e..db1278a 100644 (file)
--- a/usr.sbin/bgplgd/bgplgd.c
+++ b/usr.sbin/bgplgd/bgplgd.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: bgplgd.c,v 1.1 2022/06/28 16:11:30 claudio Exp $ */
+/*     $OpenBSD: bgplgd.c,v 1.2 2022/10/17 13:23:31 claudio Exp $ */
 /*
  * Copyright (c) 2020 Claudio Jeker <claudio@openbsd.org>
  *
@@ -26,12 +26,15 @@
 #include "bgplgd.h"
 
 #define NCMDARGS       4
+#define OMETRIC_TYPE   \
+           "application/openmetrics-text; version=1.0.0; charset=utf-8"
 
 const struct cmd {
        const char      *path;
        char            *args[NCMDARGS];
        unsigned int    qs_mask;
        int             barenbr;
+       const char      *content_type;
 } cmds[] = {
        { "/interfaces", { "show", "interfaces", NULL }, 0 },
        { "/memory", { "show", "rib", "memory", NULL }, 0 },
@@ -41,6 +44,7 @@ const struct cmd {
        { "/rtr", { "show", "rtr", NULL }, 0 },
        { "/sets", { "show", "sets", NULL }, 0 },
        { "/summary", { "show", NULL }, 0 },
+       { "/metrics", { "show", "metric", NULL }, 0, 0, OMETRIC_TYPE },
        { NULL }
 };
 
@@ -107,7 +111,10 @@ bgpctl_call(struct lg_ctx *ctx)
        signal(SIGPIPE, SIG_DFL);
 
        /* Write server header first */
-       printf("Content-type: application/json\r\n\r\n");
+       if (ctx->command->content_type == NULL)
+               printf("Content-type: application/json\r\n\r\n");
+       else
+               printf("Content-type: %s\r\n\r\n", ctx->command->content_type);
        fflush(stdout);
 
        execvp(bgpctlpath, argv);