support tcp keepalive

README.md

@@ -78,8 +78,13 @@ Synopsis
                     end
                 end
 
-                -- close
-                bean:close()
+                -- put it into the connection pool of size 100,
+                -- with 0 idle timeout
+
+                bean:set_keepalive(0, 100)
+
+                -- close and quit beanstalkd
+                -- bean:close()
            ';
         }
     }

lib/resty/beanstalkd.lua

@@ -29,6 +29,14 @@ function set_timeout(self, timeout)
     return sock:settimeout(timeout)
 end
 
+function set_keepalive(self, ...)
+    local sock = self.sock
+    if not sock then
+        return nil, "not initialized"
+    end
+    return sock:setkeepalive(...)
+end
+
 function connect(self, host, port, ...)
     local sock = self.sock
     if not sock then