[Feature] Properly implement unweighted round-robin algorithm

diff --git a/src/libutil/upstream.c b/src/libutil/upstream.c
index 0dcfea0f318cf0c7153bc8adc21262e6a3b190d4..0576525d9d4595cfc73c8ff65a6fd270856af970 100644 (file)
--- a/src/libutil/upstream.c
+++ b/src/libutil/upstream.c
@@ -36,6 +36,7 @@ struct upstream {
        guint weight;
        guint cur_weight;
        guint errors;
+       guint checked;
        guint dns_requests;
        gint active_idx;
        gchar *name;
@@ -744,35 +745,44 @@ rspamd_upstream_get_random (struct upstream_list *ups)
 static struct upstream*
 rspamd_upstream_get_round_robin (struct upstream_list *ups, gboolean use_cur)
 {
-       guint max_weight = 0;
-       struct upstream *up, *selected = NULL;
+       guint max_weight = 0, min_checked = G_MAXUINT;
+       struct upstream *up, *selected = NULL, *min_checked_sel = NULL;
        guint i;
 
        /* Select upstream with the maximum cur_weight */
        RSPAMD_UPSTREAM_LOCK (ups->lock);
+
        for (i = 0; i < ups->alive->len; i ++) {
                up = g_ptr_array_index (ups->alive, i);
                if (use_cur) {
-                       if (up->cur_weight >= max_weight) {
+                       if (up->cur_weight > max_weight) {
                                selected = up;
                                max_weight = up->cur_weight;
                        }
                }
                else {
-                       if (up->weight >= max_weight) {
+                       if (up->weight > max_weight) {
                                selected = up;
                                max_weight = up->weight;
                        }
                }
+
+               if (up->checked * (up->errors + 1) < min_checked) {
+                       min_checked_sel = up;
+                       min_checked = up->checked;
+               }
        }
 
        if (max_weight == 0) {
-               /*
-                * We actually don't have any weight information, so we could use
-                * random selection here
-                */
-               selected = g_ptr_array_index (ups->alive,
-                               ottery_rand_range (ups->alive->len - 1));
+               if (min_checked > G_MAXUINT / 2) {
+                       /* Reset all checked counters to avoid overflow */
+                       for (i = 0; i < ups->alive->len; i ++) {
+                               up = g_ptr_array_index (ups->alive, i);
+                               up->checked = 0;
+                       }
+               }
+
+               selected = min_checked_sel;
        }
 
        if (use_cur && selected) {
@@ -833,6 +843,7 @@ rspamd_upstream_get_common (struct upstream_list *ups,
                const guchar *key, gsize keylen, gboolean forced)
 {
        enum rspamd_upstream_rotation type;
+       struct upstream *up = NULL;
 
        RSPAMD_UPSTREAM_LOCK (ups->lock);
        if (ups->alive->len == 0) {
@@ -856,24 +867,32 @@ rspamd_upstream_get_common (struct upstream_list *ups,
        switch (type) {
        default:
        case RSPAMD_UPSTREAM_RANDOM:
-               return rspamd_upstream_get_random (ups);
+               up = rspamd_upstream_get_random (ups);
+               break;
        case RSPAMD_UPSTREAM_HASHED:
-               return rspamd_upstream_get_hashed (ups, key, keylen);
+               up = rspamd_upstream_get_hashed (ups, key, keylen);
+               break;
        case RSPAMD_UPSTREAM_ROUND_ROBIN:
-               return rspamd_upstream_get_round_robin (ups, TRUE);
+               up = rspamd_upstream_get_round_robin (ups, TRUE);
+               break;
        case RSPAMD_UPSTREAM_MASTER_SLAVE:
-               return rspamd_upstream_get_round_robin (ups, FALSE);
+               up = rspamd_upstream_get_round_robin (ups, FALSE);
+               break;
        case RSPAMD_UPSTREAM_SEQUENTIAL:
                if (ups->cur_elt >= ups->alive->len) {
                        ups->cur_elt = 0;
                        return NULL;
                }
 
-               return g_ptr_array_index (ups->alive, ups->cur_elt ++);
+               up = g_ptr_array_index (ups->alive, ups->cur_elt ++);
+               break;
+       }
+
+       if (up) {
+               up->checked ++;
        }
 
-       /* Silent stupid compilers */
-       return NULL;
+       return up;
 }
 
 struct upstream*