[MINOR] checks: add the server's status in the checks
Now a server can check the contents of the header X-Haproxy-Server-State
to know how haproxy sees it. The same values as those reported in the stats
are provided :
- up/down status + check counts
- throttle
- weight vs backend weight
- active sessions vs backend sessions
- queue length
- haproxy node name
diff --git a/doc/configuration.txt b/doc/configuration.txt
index 40ba6b5..b77156d 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -1936,6 +1936,49 @@
See also : "option httpchk"
+http-check send-state
+ Enable emission of a state header with HTTP health checks
+ May be used in sections : defaults | frontend | listen | backend
+ yes | no | yes | yes
+ Arguments : none
+
+ When this option is set, haproxy will systematically send a special header
+ "X-Haproxy-Server-State" with a list of parameters indicating to each server
+ how they are seen by haproxy. This can be used for instance when a server is
+ manipulated without access to haproxy and the operator needs to know whether
+ haproxy still sees it up or not, or if the server is the last one in a farm.
+
+ The header is composed of fields delimited by semi-colons, the first of which
+ is a word ("UP", "DOWN", "NOLB"), possibly followed by a number of valid
+ checks on the total number before transition, just as appears in the stats
+ interface. Next headers are in the form "<variable>=<value>", indicating in
+ no specific order some values available in the stats interface :
+ - a variable "name", containing the name of the backend followed by a slash
+ ("/") then the name of the server. This can be used when a server is
+ checked in multiple backends.
+
+ - a variable "node" containing the name of the haproxy node, as set in the
+ global "node" variable, otherwise the system's hostname if unspecified.
+
+ - a variable "weight" indicating the weight of the server, a slash ("/")
+ and the total weight of the farm (just counting usable servers). This
+ helps to know if other servers are available to handle the load when this
+ one fails.
+
+ - a variable "scur" indicating the current number of concurrent connections
+ on the server, followed by a slash ("/") then the total number of
+ connections on all servers of the same backend.
+
+ - a variable "qcur" indicating the current number of requests in the
+ server's queue.
+
+ Example of a header received by the application server :
+ >>> X-Haproxy-Server-State: UP 2/3; name=bck/srv2; node=lb1; weight=1/2; \
+ scur=13/22; qcur=0
+
+ See also : "option httpchk", "http-check disable-on-404"
+
+
id <value>
Set a persistent ID to a proxy.
May be used in sections : defaults | frontend | listen | backend
diff --git a/include/types/proxy.h b/include/types/proxy.h
index 0571f17..bdb42b9 100644
--- a/include/types/proxy.h
+++ b/include/types/proxy.h
@@ -136,6 +136,7 @@
#define PR_O2_MYSQL_CHK 0x00020000 /* use MYSQL check for server health */
#define PR_O2_USE_PXHDR 0x00040000 /* use Proxy-Connection for proxy requests */
+#define PR_O2_CHK_SNDST 0x00080000 /* send the state of each server along with HTTP health checks */
/* end of proxy->options2 */
/* bits for sticking rules */
diff --git a/src/cfgparse.c b/src/cfgparse.c
index 587a020..ef77254 100644
--- a/src/cfgparse.c
+++ b/src/cfgparse.c
@@ -2757,6 +2757,10 @@
/* enable a graceful server shutdown on an HTTP 404 response */
curproxy->options |= PR_O_DISABLE404;
}
+ else if (strcmp(args[1], "send-state") == 0) {
+ /* enable emission of the apparent state of a server in HTTP checks */
+ curproxy->options2 |= PR_O2_CHK_SNDST;
+ }
else {
Alert("parsing [%s:%d] : '%s' only supports 'disable-on-404'.\n", file, linenum, args[0]);
err_code |= ERR_ALERT | ERR_FATAL;
@@ -4676,6 +4680,13 @@
err_code |= ERR_WARN;
}
+ if ((curproxy->options2 & PR_O2_CHK_SNDST) && !(curproxy->options & PR_O_HTTP_CHK)) {
+ curproxy->options &= ~PR_O2_CHK_SNDST;
+ Warning("config : '%s' will be ignored for %s '%s' (requires 'option httpchk').\n",
+ "send-state", proxy_type_str(curproxy), curproxy->id);
+ err_code |= ERR_WARN;
+ }
+
/* if a default backend was specified, let's find it */
if (curproxy->defbe.name) {
struct proxy *target;
@@ -5045,7 +5056,7 @@
if (curproxy != px &&
(curproxy->options & PR_O_DISABLE404) != (px->options & PR_O_DISABLE404)) {
Alert("config : %s '%s', server '%s': unable to use %s/%s for"
- "tracing: disable-on-404 option inconsistency.\n",
+ "tracking: disable-on-404 option inconsistency.\n",
proxy_type_str(curproxy), curproxy->id,
newsrv->id, px->id, srv->id);
cfgerr++;
diff --git a/src/checks.c b/src/checks.c
index 3f6fa90..f59fbbe 100644
--- a/src/checks.c
+++ b/src/checks.c
@@ -629,6 +629,62 @@
}
}
+static int httpchk_build_status_header(struct server *s, char *buffer)
+{
+ int sv_state;
+ int ratio;
+ int hlen = 0;
+ const char *srv_hlt_st[7] = { "DOWN", "DOWN %d/%d",
+ "UP %d/%d", "UP",
+ "NOLB %d/%d", "NOLB",
+ "no check" };
+
+ memcpy(buffer + hlen, "X-Haproxy-Server-State: ", 24);
+ hlen += 24;
+
+ if (!(s->state & SRV_CHECKED))
+ sv_state = 6; /* should obviously never happen */
+ else if (s->state & SRV_RUNNING) {
+ if (s->health == s->rise + s->fall - 1)
+ sv_state = 3; /* UP */
+ else
+ sv_state = 2; /* going down */
+
+ if (s->state & SRV_GOINGDOWN)
+ sv_state += 2;
+ } else {
+ if (s->health)
+ sv_state = 1; /* going up */
+ else
+ sv_state = 0; /* DOWN */
+ }
+
+ hlen += sprintf(buffer + hlen,
+ srv_hlt_st[sv_state],
+ (s->state & SRV_RUNNING) ? (s->health - s->rise + 1) : (s->health),
+ (s->state & SRV_RUNNING) ? (s->fall) : (s->rise));
+
+ hlen += sprintf(buffer + hlen, "; name=%s/%s; node=%s; weight=%d/%d; scur=%d/%d; qcur=%d",
+ s->proxy->id, s->id,
+ global.node,
+ (s->eweight * s->proxy->lbprm.wmult + s->proxy->lbprm.wdiv - 1) / s->proxy->lbprm.wdiv,
+ (s->proxy->lbprm.tot_weight * s->proxy->lbprm.wmult + s->proxy->lbprm.wdiv - 1) / s->proxy->lbprm.wdiv,
+ s->cur_sess, s->proxy->beconn - s->proxy->nbpend,
+ s->nbpend);
+
+ if ((s->state & SRV_WARMINGUP) &&
+ now.tv_sec < s->last_change + s->slowstart &&
+ now.tv_sec >= s->last_change) {
+ ratio = MAX(1, 100 * (now.tv_sec - s->last_change) / s->slowstart);
+ hlen += sprintf(buffer + hlen, "; throttle=%d%%", ratio);
+ }
+
+ buffer[hlen++] = '\r';
+ buffer[hlen++] = '\n';
+
+ return hlen;
+}
+
/*
* This function is used only for server health-checks. It handles
* the connection acknowledgement. If the proxy requires L7 health-checks,
@@ -678,6 +734,10 @@
}
else if (s->proxy->options & PR_O_HTTP_CHK) {
memcpy(trash, check_req, check_len);
+
+ if (s->proxy->options2 & PR_O2_CHK_SNDST)
+ check_len += httpchk_build_status_header(s, trash + check_len);
+
trash[check_len++] = '\r';
trash[check_len++] = '\n';
trash[check_len] = '\0';