[MEDIUM] support setting a server weight to zero
Sometimes it is useful to be able to set a server's weight to zero.
It allows the server to receive only persistent traffic but never
normal traffic.
diff --git a/doc/configuration.txt b/doc/configuration.txt
index cf30c15..89525e8 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -4476,11 +4476,12 @@
The "weight" parameter is used to adjust the server's weight relative to
other servers. All servers will receive a load proportional to their weight
relative to the sum of all weights, so the higher the weight, the higher the
- load. The default weight is 1, and the maximal value is 255. If this
- parameter is used to distribute the load according to server's capacity, it
- is recommended to start with values which can both grow and shrink, for
- instance between 10 and 100 to leave enough room above and below for later
- adjustments.
+ load. The default weight is 1, and the maximal value is 256. A value of 0
+ means the server will not participate in load-balancing but will still accept
+ persistent connections. If this parameter is used to distribute the load
+ according to server's capacity, it is recommended to start with values which
+ can both grow and shrink, for instance between 10 and 100 to leave enough
+ room above and below for later adjustments.
6. HTTP header manipulation
diff --git a/src/backend.c b/src/backend.c
index 58de35e..5cea808 100644
--- a/src/backend.c
+++ b/src/backend.c
@@ -203,7 +203,8 @@
int max = 0;
best = NULL;
for (cur = px->srv; cur; cur = cur->next) {
- if (flag == (cur->state &
+ if (cur->eweight &&
+ flag == (cur->state &
(SRV_RUNNING | SRV_GOINGDOWN | SRV_BACKUP))) {
int v;
@@ -250,15 +251,24 @@
return;
/* We will factor the weights to reduce the table,
- * using Euclide's largest common divisor algorithm
+ * using Euclide's largest common divisor algorithm.
+ * Since we may have zero weights, we have to first
+ * find a non-zero weight server.
*/
- pgcd = p->srv->uweight;
- for (srv = p->srv->next; srv && pgcd > 1; srv = srv->next) {
- int w = srv->uweight;
- while (w) {
- int t = pgcd % w;
- pgcd = w;
- w = t;
+ pgcd = 1;
+ srv = p->srv;
+ while (srv && !srv->uweight)
+ srv = srv->next;
+
+ if (srv) {
+ pgcd = srv->uweight; /* note: cannot be zero */
+ while (pgcd > 1 && (srv = srv->next)) {
+ int w = srv->uweight;
+ while (w) {
+ int t = pgcd % w;
+ pgcd = w;
+ w = t;
+ }
}
}
@@ -283,6 +293,9 @@
if (act < bck)
act = bck;
+ if (!act)
+ act = 1;
+
p->lbprm.map.srv = (struct server **)calloc(act, sizeof(struct server *));
/* recounts servers and their weights */
p->lbprm.map.state = PR_MAP_RECALC;
diff --git a/src/cfgparse.c b/src/cfgparse.c
index 413aeae..6c00651 100644
--- a/src/cfgparse.c
+++ b/src/cfgparse.c
@@ -2185,8 +2185,8 @@
else if (!strcmp(args[cur_arg], "weight")) {
int w;
w = atol(args[cur_arg + 1]);
- if (w < 1 || w > 256) {
- Alert("parsing [%s:%d] : weight of server %s is not within 1 and 256 (%d).\n",
+ if (w < 0 || w > 256) {
+ Alert("parsing [%s:%d] : weight of server %s is not within 0 and 256 (%d).\n",
file, linenum, newsrv->id, w);
return -1;
}