fix: avoid caching outdated discovery upstream nodes

apisix/balancer.lua

@@ -67,7 +67,7 @@ local function fetch_health_nodes(upstream, checker)
     end
 
     if core.table.nkeys(up_nodes) == 0 then
-        core.log.warn("all upstream nodes is unhealth, use default")
+        core.log.warn("all upstream nodes is unhealthy, use default")
         for _, node in ipairs(nodes) do
             up_nodes[node.host .. ":" .. node.port] = node.weight
         end

apisix/http/service.lua

@@ -47,7 +47,13 @@ local function filter(service)
         return
     end
 
-    if not service.value.upstream or not service.value.upstream.nodes then
+    if not service.value.upstream then
+        return
+    end
+
+    service.value.upstream.parent = service
+
+    if not service.value.upstream.nodes then
         return
     end
 
@@ -79,7 +85,6 @@ local function filter(service)
         service.value.upstream.nodes = new_nodes
     end
 
-    service.value.upstream.parent = service
     core.log.info("filter service: ", core.json.delay_encode(service))
 end
 

apisix/init.lua

@@ -24,6 +24,7 @@ local admin_init    = require("apisix.admin.init")
 local get_var       = require("resty.ngxvar").fetch
 local router        = require("apisix.router")
 local set_upstream  = require("apisix.upstream").set_by_route
+local upstream_util = require("apisix.utils.upstream")
 local ipmatcher     = require("resty.ipmatcher")
 local ngx           = ngx
 local get_method    = ngx.req.get_method
@@ -32,7 +33,6 @@ local math          = math
 local error         = error
 local ipairs        = ipairs
 local tostring      = tostring
-local type          = type
 local ngx_now       = ngx.now
 local str_byte      = string.byte
 local str_sub       = string.sub
@@ -237,29 +237,6 @@ local function parse_domain_for_nodes(nodes)
 end
 
 
-local function compare_upstream_node(old_t, new_t)
-    if type(old_t) ~= "table" then
-        return false
-    end
-
-    if #new_t ~= #old_t then
-        return false
-    end
-
-    for i = 1, #new_t do
-        local new_node = new_t[i]
-        local old_node = old_t[i]
-        for _, name in ipairs({"host", "port", "weight"}) do
-            if new_node[name] ~= old_node[name] then
-                return false
-            end
-        end
-    end
-
-    return true
-end
-
-
 local function parse_domain_in_up(up)
     local nodes = up.value.nodes
     local new_nodes, err = parse_domain_for_nodes(nodes)
@@ -268,7 +245,7 @@ local function parse_domain_in_up(up)
     end
 
     local old_dns_value = up.dns_value and up.dns_value.nodes
-    local ok = compare_upstream_node(old_dns_value, new_nodes)
+    local ok = upstream_util.compare_upstream_node(old_dns_value, new_nodes)
     if ok then
         return up
     end
@@ -291,7 +268,7 @@ local function parse_domain_in_route(route)
     end
 
     local old_dns_value = route.dns_value and route.dns_value.upstream.nodes
-    local ok = compare_upstream_node(old_dns_value, new_nodes)
+    local ok = upstream_util.compare_upstream_node(old_dns_value, new_nodes)
     if ok then
         return route
     end

apisix/plugin.lua

@@ -418,8 +418,8 @@ end
 
 
 function _M.merge_service_route(service_conf, route_conf)
-    core.log.info("service conf: ", core.json.delay_encode(service_conf))
-    core.log.info("  route conf: ", core.json.delay_encode(route_conf))
+    core.log.info("service conf: ", core.json.delay_encode(service_conf, true))
+    core.log.info("  route conf: ", core.json.delay_encode(route_conf, true))
 
     local route_service_key = route_conf.value.id .. "#"
         .. route_conf.modifiedIndex .. "#" .. service_conf.modifiedIndex

apisix/router.lua

@@ -32,7 +32,13 @@ local function filter(route)
         return
     end
 
-    if not route.value.upstream or not route.value.upstream.nodes then
+    if not route.value.upstream then
+        return
+    end
+
+    route.value.upstream.parent = route
+
+    if not route.value.upstream.nodes then
         return
     end
 
@@ -64,7 +70,6 @@ local function filter(route)
         route.value.upstream.nodes = new_nodes
     end
 
-    route.value.upstream.parent = route
     core.log.info("filter route: ", core.json.delay_encode(route))
 end
 

apisix/upstream.lua

@@ -17,6 +17,7 @@
 local require = require
 local core = require("apisix.core")
 local discovery = require("apisix.discovery.init").discovery
+local upstream_util = require("apisix.utils.upstream")
 local error = error
 local tostring = tostring
 local ipairs = ipairs
@@ -132,9 +133,26 @@ function _M.set_by_route(route, api_ctx)
 
         local dis = discovery[up_conf.discovery_type]
         if not dis then
-            return 500, "discovery " .. up_conf.discovery_type .. "is uninitialized"
+            return 500, "discovery " .. up_conf.discovery_type .. " is uninitialized"
+        end
+        local new_nodes = dis.nodes(up_conf.service_name)
+        local same = upstream_util.compare_upstream_node(up_conf.nodes, new_nodes)
+        if not same then
+            up_conf.nodes = new_nodes
+            local new_up_conf = core.table.clone(up_conf)
+            core.log.info("discover new upstream from ", up_conf.service_name, ", type ",
+                          up_conf.discovery_type, ": ",
+                          core.json.delay_encode(new_up_conf, true))
+
+            local parent = up_conf.parent
+            if parent.value.upstream then
+                -- the up_conf comes from route or service
+                parent.value.upstream = new_up_conf
+            else
+                parent.value = new_up_conf
+            end
+            up_conf = new_up_conf
         end
-        up_conf.nodes = dis.nodes(up_conf.service_name)
     end
 
     set_directly(api_ctx, up_conf.type .. "#upstream_" .. tostring(up_conf),
@@ -175,7 +193,13 @@ function _M.init_worker()
             item_schema = core.schema.upstream,
             filter = function(upstream)
                 upstream.has_domain = false
-                if not upstream.value or not upstream.value.nodes then
+                if not upstream.value then
+                    return
+                end
+
+                upstream.value.parent = upstream
+
+                if not upstream.value.nodes then
                     return
                 end
 
@@ -207,7 +231,6 @@ function _M.init_worker()
                     upstream.value.nodes = new_nodes
                 end
 
-                upstream.value.parent = upstream
                 core.log.info("filter upstream: ", core.json.delay_encode(upstream))
             end,
         })

apisix/utils/upstream.lua

@@ -0,0 +1,56 @@
+--
+-- Licensed to the Apache Software Foundation (ASF) under one or more
+-- contributor license agreements.  See the NOTICE file distributed with
+-- this work for additional information regarding copyright ownership.
+-- The ASF licenses this file to You under the Apache License, Version 2.0
+-- (the "License"); you may not use this file except in compliance with
+-- the License.  You may obtain a copy of the License at
+--
+--     http://www.apache.org/licenses/LICENSE-2.0
+--
+-- Unless required by applicable law or agreed to in writing, software
+-- distributed under the License is distributed on an "AS IS" BASIS,
+-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+-- See the License for the specific language governing permissions and
+-- limitations under the License.
+--
+local core = require("apisix.core")
+local ipairs = ipairs
+local type = type
+
+
+local _M = {}
+
+
+local function sort_by_key_host(a, b)
+    return a.host < b.host
+end
+
+
+function _M.compare_upstream_node(old_t, new_t)
+    if type(old_t) ~= "table" then
+        return false
+    end
+
+    if #new_t ~= #old_t then
+        return false
+    end
+
+    core.table.sort(old_t, sort_by_key_host)
+    core.table.sort(new_t, sort_by_key_host)
+
+    for i = 1, #new_t do
+        local new_node = new_t[i]
+        local old_node = old_t[i]
+        for _, name in ipairs({"host", "port", "weight"}) do
+            if new_node[name] ~= old_node[name] then
+                return false
+            end
+        end
+    end
+
+    return true
+end
+
+
+return _M