bugfix: balancer_by_lua*: the number of retres might exceed the limit of proxy_next_upstream_tries or alike.

Signed-off-by: Yichun Zhang (agentzh) <agentzh@gmail.com>

Author: qleex001

.travis.yml

@@ -79,6 +79,7 @@ install:
   - git clone https://github.com/openresty/rds-json-nginx-module.git ../rds-json-nginx-module
   - git clone https://github.com/openresty/srcache-nginx-module.git ../srcache-nginx-module
   - git clone https://github.com/openresty/redis2-nginx-module.git ../redis2-nginx-module
+  - git clone https://github.com/openresty/lua-resty-core.git ../lua-resty-core
   - git clone -b v2.1-agentzh https://github.com/openresty/luajit2.git
 
 before_script:

src/ngx_http_lua_balancer.c

@@ -640,7 +640,7 @@ ngx_http_lua_ffi_balancer_set_more_tries(ngx_http_request_t *r,
     int count, char **err)
 {
 #if (nginx_version >= 1007005)
-    ngx_uint_t             max_tries;
+    ngx_uint_t             max_tries, total;
 #endif
     ngx_http_lua_ctx_t    *ctx;
     ngx_http_upstream_t   *u;
@@ -681,9 +681,10 @@ ngx_http_lua_ffi_balancer_set_more_tries(ngx_http_request_t *r,
 
 #if (nginx_version >= 1007005)
     max_tries = r->upstream->conf->next_upstream_tries;
+    total = bp->total_tries + r->upstream->peer.tries - 1;
 
-    if (bp->total_tries + count > max_tries) {
-        count = max_tries - bp->total_tries;
+    if (max_tries && total + count > max_tries) {
+        count = max_tries - total;
         *err = "reduced tries due to limit";
 
     } else {

t/138-balancer.t

@@ -431,3 +431,60 @@ qr{\[crit\] .*? connect\(\) to 0\.0\.0\.1:80 failed .*?, upstream: "http://0\.0\
 ]
 --- no_error_log
 [warn]
+
+
+
+=== TEST 15: test if execeed proxy_next_upstream_limit
+--- http_config
+    lua_package_path "../lua-resty-core/lib/?.lua;;";
+
+    proxy_next_upstream_tries 5;
+    upstream backend {
+        server 0.0.0.1;
+        balancer_by_lua_block {
+            local b = require "ngx.balancer"
+
+            if not ngx.ctx.tries then
+                ngx.ctx.tries = 0
+            end
+
+            if ngx.ctx.tries >= 6 then
+                ngx.log(ngx.ERR, "retry count exceed limit")
+                ngx.exit(500)
+            end
+
+            ngx.ctx.tries = ngx.ctx.tries + 1
+            print("retry counter: ", ngx.ctx.tries)
+
+            local ok, err = b.set_more_tries(2)
+            if not ok then
+                return error("failed to set more tries: ", err)
+            elseif err then
+                ngx.log(ngx.WARN, "set more tries: ", err)
+            end
+
+            assert(b.set_current_peer("127.0.0.1", 81))
+        }
+    }
+--- config
+    location = /t {
+        proxy_pass http://backend/back;
+    }
+
+    location = /back {
+        return 404;
+    }
+--- request
+    GET /t
+--- response_body_like: 502 Bad Gateway
+--- error_code: 502
+--- grep_error_log eval: qr/\bretry counter: \w+/
+--- grep_error_log_out
+retry counter: 1
+retry counter: 2
+retry counter: 3
+retry counter: 4
+retry counter: 5
+
+--- error_log
+set more tries: reduced tries due to limit