fix(batch-requests): missing the port number error when APISIX listens on a unix socket

apisix/plugins/batch-requests.lua

@@ -20,6 +20,7 @@ local plugin    = require("apisix.plugin")
 local ngx       = ngx
 local ipairs    = ipairs
 local pairs     = pairs
+local type      = type
 local str_find  = core.string.find
 local str_lower = string.lower
 
@@ -224,6 +225,50 @@ local function set_common_query(data)
 end
 
 
+-- When the request is received on a unix domain socket, $server_port is an
+-- empty string, so we fall back to a TCP port from `apisix.node_listen`.
+-- The value read from the local conf is not normalized by the CLI, so it can
+-- be a plain port number, or an array of port numbers or `{ip, port}` tables.
+-- An entry bound to a specific address is only used as a last resort, as the
+-- loopback connect below targets 127.0.0.1 and would otherwise be refused.
+local function get_loopback_port()
+    local server_port = ngx.var.server_port
+    if server_port and server_port ~= "" then
+        return server_port
+    end
+
+    local local_conf = core.config.local_conf()
+    local node_listen = core.table.try_read_attr(local_conf, "apisix", "node_listen")
+    if type(node_listen) == "number" then
+        return node_listen
+    end
+
+    if type(node_listen) == "table" then
+        local bound_port
+        for _, value in ipairs(node_listen) do
+            if type(value) == "number" then
+                return value
+            end
+
+            if type(value) == "table" then
+                -- the port defaults to 9080 if not set, see `apisix/cli/ops.lua`
+                local port = value.port or 9080
+                local ip = value.ip
+                if ip == nil or ip == "0.0.0.0" or ip == "127.0.0.1" then
+                    return port
+                end
+
+                bound_port = bound_port or port
+            end
+        end
+
+        return bound_port
+    end
+
+    return nil
+end
+
+
 local function batch_requests(ctx)
     local metadata = plugin.plugin_metadata(plugin_name)
     core.log.info("metadata: ", core.json.delay_encode(metadata))
@@ -269,9 +314,17 @@ local function batch_requests(ctx)
         }
     end
 
+    local server_port = get_loopback_port()
+    if not server_port then
+        return 503, {
+            error_msg = "this APISIX instance doesn't listen on a TCP port, " ..
+                        "but the batch-requests plugin needs one to loop back requests"
+        }
+    end
+
     local httpc = http.new()
     httpc:set_timeout(data.timeout)
-    local ok, err = httpc:connect("127.0.0.1", ngx.var.server_port)
+    local ok, err = httpc:connect("127.0.0.1", server_port)
     if not ok then
         return 500, {error_msg = "connect to apisix failed: " .. err}
     end

t/plugin/batch-requests.t

@@ -1194,3 +1194,133 @@ qr/property \\"path\\" is required/
 GET /t
 --- response_body
 passed
+
+
+
+=== TEST 31: aggregate requests arriving via a unix domain socket
+--- config
+    listen unix:$TEST_NGINX_HTML_DIR/apisix.sock;
+
+    location = /t {
+        content_by_lua_block {
+            local core = require("apisix.core")
+            local json = require("toolkit.json")
+            local http = require("resty.http")
+            local httpc = http.new()
+            httpc:set_timeout(2000)
+            local ok, err = httpc:connect("unix:$TEST_NGINX_HTML_DIR/apisix.sock")
+            if not ok then
+                ngx.say("failed to connect: ", err)
+                return
+            end
+
+            local body = core.json.encode({
+                pipeline = {
+                    {path = "/uds-b"},
+                    {path = "/uds-c", method = "PUT"},
+                }
+            })
+
+            local res, err = httpc:request({
+                method = "POST",
+                path = "/apisix/batch-requests",
+                headers = {
+                    ["Host"] = "127.0.0.1",
+                    ["Content-Type"] = "application/json",
+                },
+                body = body,
+            })
+            if not res then
+                ngx.say("request failed: ", err)
+                return
+            end
+
+            local resp_body, err = res:read_body()
+            if not resp_body then
+                ngx.say("failed to read response body: ", err)
+                return
+            end
+
+            if res.status ~= 200 then
+                ngx.status = res.status
+                ngx.print(resp_body)
+                return
+            end
+
+            local data = json.decode(resp_body)
+            for _, resp in ipairs(data) do
+                ngx.say(resp.status, " ", resp.body)
+            end
+        }
+    }
+
+    location = /uds-b {
+        content_by_lua_block {
+            ngx.print("B")
+        }
+    }
+    location = /uds-c {
+        content_by_lua_block {
+            ngx.status = 201
+            ngx.print("C")
+        }
+    }
+--- request
+GET /t
+--- response_body
+200 B
+201 C
+
+
+
+=== TEST 32: no TCP port to loop back through
+--- yaml_config
+apisix:
+  node_listen: []
+  enable_resolv_search_opt: false
+  trusted_addresses:
+    - "127.0.0.1"
+--- config
+    listen unix:$TEST_NGINX_HTML_DIR/apisix.sock;
+
+    location = /t {
+        content_by_lua_block {
+            local core = require("apisix.core")
+            local http = require("resty.http")
+            local httpc = http.new()
+            httpc:set_timeout(2000)
+            local ok, err = httpc:connect("unix:$TEST_NGINX_HTML_DIR/apisix.sock")
+            if not ok then
+                ngx.say("failed to connect: ", err)
+                return
+            end
+
+            local body = core.json.encode({pipeline = {{path = "/uds-b"}}})
+            local res, err = httpc:request({
+                method = "POST",
+                path = "/apisix/batch-requests",
+                headers = {
+                    ["Host"] = "127.0.0.1",
+                    ["Content-Type"] = "application/json",
+                },
+                body = body,
+            })
+            if not res then
+                ngx.say("request failed: ", err)
+                return
+            end
+
+            local resp_body = res:read_body()
+            ngx.say(res.status, " ", resp_body)
+        }
+    }
+
+    location = /uds-b {
+        content_by_lua_block {
+            ngx.print("B")
+        }
+    }
+--- request
+GET /t
+--- response_body_like
+503 .*doesn't listen on a TCP port.*