MINOR: ext-check: indicate the transport and protocol of a server

Valerio Pachera explained [1] that external checks would benefit from
having a variable indicating if SSL is being used or not on the server
being checked, and the discussion derived to also indicating the protocol
in use.

This patch adds two environment variables for external checks:
  - HAPROXY_SERVER_SSL: equals "0" when SSL is not used, "1" when it is
  - HAPROXY_SERVER_PROTO: contains one of the following words to describe
    the protocol used with this server:
      - "cli": the haproxy CLI. Normally not seen
      - "syslog": this is a syslog TCP server
      - "peers": this is a peers TCP server
      - "h1": this is an HTTP/1.x server
      - "h2": this is an HTTP/2 server
      - "tcp": this is any other TCP server

The patch is very simple, and may be backported to recent versions if
needed. This closes github issue #1692.

[1] https://www.mail-archive.com/haproxy@formilux.org/msg42233.html

diff --git a/doc/configuration.txt b/doc/configuration.txt
index 96210d80295b6bf43e589e82471ce2e2da082300..d0a2915ffabec494643504ba7d6f388dace92341 100644 (file)
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -10085,6 +10085,14 @@ external-check command <command>
     HAPROXY_SERVER_PORT     The server port if available (or empty for a UNIX
                             socket).
 
+    HAPROXY_SERVER_SSL      "0" when SSL is not used, "1" when it is used
+
+    HAPROXY_SERVER_PROTO    The protocol used by this server, which can be one
+                            of "cli" (the haproxy CLI), "syslog" (syslog TCP
+                            server), "peers" (peers TCP server), "h1" (HTTP/1.x
+                            server), "h2" (HTTP/2 server), or "tcp" (any other
+                            TCP server).
+
     PATH                    The PATH environment variable used when executing
                             the command may be set using "external-check path".
 

diff --git a/src/extcheck.c b/src/extcheck.c
index 0d2194a1a59a169bf6ce701eee7b08c861d9c24e..7b3dbbaf11d04d183788c94856f6e166fb812597 100644 (file)
--- a/src/extcheck.c
+++ b/src/extcheck.c
@@ -74,6 +74,8 @@ enum {
        EXTCHK_HAPROXY_SERVER_PORT,     /* the server port if available (or empty) */
        EXTCHK_HAPROXY_SERVER_MAXCONN,  /* the server max connections */
        EXTCHK_HAPROXY_SERVER_CURCONN,  /* the current number of connections on the server */
+       EXTCHK_HAPROXY_SERVER_SSL,      /* "1" if the server supports SSL, otherwise zero */
+       EXTCHK_HAPROXY_SERVER_PROTO,    /* the server's configured proto, if any */
 
        EXTCHK_SIZE
 };
@@ -90,6 +92,8 @@ const struct extcheck_env extcheck_envs[EXTCHK_SIZE] = {
        [EXTCHK_HAPROXY_SERVER_PORT]    = { "HAPROXY_SERVER_PORT",    EXTCHK_SIZE_UINT },
        [EXTCHK_HAPROXY_SERVER_MAXCONN] = { "HAPROXY_SERVER_MAXCONN", EXTCHK_SIZE_EVAL_INIT },
        [EXTCHK_HAPROXY_SERVER_CURCONN] = { "HAPROXY_SERVER_CURCONN", EXTCHK_SIZE_ULONG },
+       [EXTCHK_HAPROXY_SERVER_SSL]     = { "HAPROXY_SERVER_SSL",     EXTCHK_SIZE_UINT },
+       [EXTCHK_HAPROXY_SERVER_PROTO]   = { "HAPROXY_SERVER_PROTO",   EXTCHK_SIZE_EVAL_INIT },
 };
 
 void block_sigchld(void)
@@ -262,6 +266,7 @@ int prepare_external_check(struct check *check)
        int i;
        const char *path = px->check_path ? px->check_path : DEF_CHECK_PATH;
        char buf[256];
+       const char *svmode = NULL;
 
        list_for_each_entry(l, &px->conf.listeners, by_fe)
                /* Use the first INET, INET6 or UNIX listener */
@@ -334,6 +339,18 @@ int prepare_external_check(struct check *check)
        EXTCHK_SETENV(check, EXTCHK_HAPROXY_SERVER_PORT, check->argv[4], err);
        EXTCHK_SETENV(check, EXTCHK_HAPROXY_SERVER_MAXCONN, ultoa_r(s->maxconn, buf, sizeof(buf)), err);
        EXTCHK_SETENV(check, EXTCHK_HAPROXY_SERVER_CURCONN, ultoa_r(s->cur_sess, buf, sizeof(buf)), err);
+       EXTCHK_SETENV(check, EXTCHK_HAPROXY_SERVER_SSL, s->use_ssl ? "1" : "0", err);
+
+       switch (px->mode) {
+       case PR_MODE_CLI:    svmode = "cli"; break;
+       case PR_MODE_SYSLOG: svmode = "syslog"; break;
+       case PR_MODE_PEERS:  svmode = "peers"; break;
+       case PR_MODE_HTTP:   svmode = (s->mux_proto) ? s->mux_proto->token.ptr : "h1"; break;
+       case PR_MODE_TCP:    svmode = "tcp"; break;
+       /* all valid cases must be enumerated above, below is to avoid a warning */
+       case PR_MODES:       svmode = "?"; break;
+       }
+       EXTCHK_SETENV(check, EXTCHK_HAPROXY_SERVER_PROTO, svmode, err);
 
        /* Ensure that we don't leave any hole in check->envp */
        for (i = 0; i < EXTCHK_SIZE; i++)