| -- |
| -- 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 config_local = require("apisix.core.config_local") |
| local ipairs = ipairs |
| local error = error |
| |
| |
| local dns_client |
| local schema = { |
| type = "object", |
| properties = { |
| servers = { |
| type = "array", |
| minItems = 1, |
| items = { |
| type = "string", |
| }, |
| }, |
| }, |
| required = {"servers"} |
| } |
| |
| |
| local _M = {} |
| |
| |
| function _M.nodes(service_name) |
| local host, port = core.utils.parse_addr(service_name) |
| core.log.info("discovery dns with host ", host, ", port ", port) |
| |
| local records, err = dns_client:resolve(host, core.dns_client.RETURN_ALL) |
| if not records then |
| return nil, err |
| end |
| |
| local nodes = core.table.new(#records, 0) |
| for i, r in ipairs(records) do |
| if r.address then |
| nodes[i] = {host = r.address, weight = r.weight or 1, port = r.port or port} |
| if r.priority then |
| -- for SRV record, nodes with lower priority are chosen first |
| nodes[i].priority = -r.priority |
| end |
| end |
| end |
| |
| return nodes |
| end |
| |
| |
| function _M.init_worker() |
| local local_conf = config_local.local_conf() |
| local ok, err = core.schema.check(schema, local_conf.discovery.dns) |
| if not ok then |
| error("invalid dns discovery configuration: " .. err) |
| return |
| end |
| |
| local servers = core.table.try_read_attr(local_conf, "discovery", "dns", "servers") |
| |
| local opts = { |
| hosts = {}, |
| resolvConf = {}, |
| nameservers = servers, |
| order = {"last", "A", "AAAA", "SRV", "CNAME"}, |
| } |
| |
| local client, err = core.dns_client.new(opts) |
| if not client then |
| error("failed to init the dns client: ", err) |
| return |
| end |
| |
| dns_client = client |
| end |
| |
| |
| return _M |