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Posted to notifications@apisix.apache.org by GitBox <gi...@apache.org> on 2022/04/19 01:49:37 UTC
[GitHub] [apisix] leslie-tsang commented on a diff in pull request #6873: feat(xRPC): simple redis support
leslie-tsang commented on code in PR #6873:
URL: https://github.com/apache/apisix/pull/6873#discussion_r852529127
##########
apisix/stream/xrpc/protocols/redis/init.lua:
##########
@@ -0,0 +1,239 @@
+--
+-- 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 sdk = require("apisix.stream.xrpc.sdk")
+local xrpc_socket = require("resty.apisix.stream.xrpc.socket")
+local ffi = require("ffi")
+local ffi_str = ffi.string
+local math_random = math.random
+local OK = ngx.OK
+local DECLINED = ngx.DECLINED
+local DONE = ngx.DONE
+local str_byte = string.byte
+local str_fmt = string.format
+local tonumber = tonumber
+
+
+-- redis protocol spec: https://redis.io/docs/reference/protocol-spec/
+-- There is no plan to support inline command format
+local _M = {}
+local MAX_LINE_LEN = 128
+local PREFIX_ARR = str_byte("*")
+local PREFIX_STR = str_byte("$")
+local PREFIX_STA = str_byte("+")
+local PREFIX_INT = str_byte(":")
+local PREFIX_ERR = str_byte("-")
+
+
+function _M.init_downstream(session)
+ return xrpc_socket.downstream.socket()
+end
+
+
+local function read_line(sk)
+ local p, err, len = sk:read_line(MAX_LINE_LEN)
+ if not p then
+ return nil, err
+ end
+
+ if len < 2 then
+ return nil, "line too short"
+ end
+
+ return p, nil, len
+end
+
+
+local function read_len(sk)
+ local p, err, len = read_line(sk)
+ if not p then
+ return nil, err
+ end
+
+ local s = ffi_str(p + 1, len - 1)
+ local n = tonumber(s)
+ if not n then
+ return nil, str_fmt("invalid len string: \"%s\"", s)
+ end
+ return n
+end
+
+
+local function read_req(sk)
+ local narg, err = read_len(sk)
+ if not narg then
+ return nil, err
+ end
+
+ local ctx = {
+ cmd_line = core.table.new(narg, 0)
+ }
+
+ for i = 1, narg do
+ local n, err = read_len(sk)
+ if not n then
+ return nil, err
+ end
+
+ local p, err = sk:read(n + 2)
+ if not p then
+ return nil, err
+ end
+
+ local s = ffi_str(p, n)
+ ctx.cmd_line[i] = s
+ end
+
+ ctx.cmd = ctx.cmd_line[1]
+ return ctx
+end
+
+
+local function read_reply(sk)
+ local line, err, n = read_line(sk)
+ if not line then
+ return nil, err
+ end
+
+ local prefix = line[0]
+
+ if prefix == PREFIX_STR then -- char '$'
+ -- print("bulk reply")
+
+ local size = tonumber(ffi_str(line + 1, n - 1))
+ if size < 0 then
+ -- return null
+ return true
+ end
+
+ local ok, err = sk:drain(size + 2)
+ if not ok then
+ return nil, err
+ end
+
+ return true
+
+ elseif prefix == PREFIX_STA then -- char '+'
+ -- print("status reply")
+ -- return sub(line, 2)
+ return true
+
+ elseif prefix == PREFIX_ARR then -- char '*'
+ local narr = tonumber(ffi_str(line + 1, n - 1))
+
+ -- print("multi-bulk reply: ", narr)
+ if narr < 0 then
+ -- return null
Review Comment:
Shall we remove these comment ?
##########
apisix/stream/xrpc/protocols/redis/init.lua:
##########
@@ -0,0 +1,239 @@
+--
+-- 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 sdk = require("apisix.stream.xrpc.sdk")
+local xrpc_socket = require("resty.apisix.stream.xrpc.socket")
+local ffi = require("ffi")
+local ffi_str = ffi.string
+local math_random = math.random
+local OK = ngx.OK
+local DECLINED = ngx.DECLINED
+local DONE = ngx.DONE
+local str_byte = string.byte
+local str_fmt = string.format
+local tonumber = tonumber
+
+
+-- redis protocol spec: https://redis.io/docs/reference/protocol-spec/
+-- There is no plan to support inline command format
+local _M = {}
+local MAX_LINE_LEN = 128
+local PREFIX_ARR = str_byte("*")
+local PREFIX_STR = str_byte("$")
+local PREFIX_STA = str_byte("+")
+local PREFIX_INT = str_byte(":")
+local PREFIX_ERR = str_byte("-")
+
+
+function _M.init_downstream(session)
+ return xrpc_socket.downstream.socket()
+end
+
+
+local function read_line(sk)
+ local p, err, len = sk:read_line(MAX_LINE_LEN)
+ if not p then
+ return nil, err
+ end
+
+ if len < 2 then
+ return nil, "line too short"
+ end
+
+ return p, nil, len
+end
+
+
+local function read_len(sk)
+ local p, err, len = read_line(sk)
+ if not p then
+ return nil, err
+ end
+
+ local s = ffi_str(p + 1, len - 1)
+ local n = tonumber(s)
+ if not n then
+ return nil, str_fmt("invalid len string: \"%s\"", s)
+ end
+ return n
+end
+
+
+local function read_req(sk)
+ local narg, err = read_len(sk)
+ if not narg then
+ return nil, err
+ end
+
+ local ctx = {
+ cmd_line = core.table.new(narg, 0)
+ }
+
+ for i = 1, narg do
+ local n, err = read_len(sk)
+ if not n then
+ return nil, err
+ end
+
+ local p, err = sk:read(n + 2)
+ if not p then
+ return nil, err
+ end
+
+ local s = ffi_str(p, n)
+ ctx.cmd_line[i] = s
+ end
+
+ ctx.cmd = ctx.cmd_line[1]
+ return ctx
+end
+
+
+local function read_reply(sk)
+ local line, err, n = read_line(sk)
+ if not line then
+ return nil, err
+ end
+
+ local prefix = line[0]
+
+ if prefix == PREFIX_STR then -- char '$'
+ -- print("bulk reply")
+
+ local size = tonumber(ffi_str(line + 1, n - 1))
+ if size < 0 then
+ -- return null
+ return true
+ end
+
+ local ok, err = sk:drain(size + 2)
+ if not ok then
+ return nil, err
+ end
+
+ return true
+
+ elseif prefix == PREFIX_STA then -- char '+'
+ -- print("status reply")
+ -- return sub(line, 2)
+ return true
+
+ elseif prefix == PREFIX_ARR then -- char '*'
+ local narr = tonumber(ffi_str(line + 1, n - 1))
+
+ -- print("multi-bulk reply: ", narr)
+ if narr < 0 then
+ -- return null
+ return true
+ end
+
+ local vals = core.table.new(n, 0)
+ local nvals = 0
+ for i = 1, narr do
+ local res, err = read_reply(sk)
+ if res then
+ nvals = nvals + 1
+ vals[nvals] = res
+
+ elseif res == nil then
+ return nil, err
+
+ else
+ -- be a valid redis error value
+ nvals = nvals + 1
+ vals[nvals] = {false, err}
+ end
+ end
+
+ return vals
+
+ elseif prefix == PREFIX_INT then -- char ':'
+ -- print("integer reply")
+ -- return tonumber(str_sub(line, 2))
+ return true
+
+ elseif prefix == PREFIX_ERR then -- char '-'
+ -- print("error reply: ", n)
+ -- return false, str_sub(line, 2)
+ return true
+
+ else
+ return nil, str_fmt("unknown prefix: \"%s\"", prefix)
+ end
+end
+
+
+function _M.from_downstream(session, downstream)
+ local ctx, err = read_req(downstream)
+ if not ctx then
+ if err ~= "timeout" and err ~= "closed" then
+ core.log.error("failed to read request: ", err)
+ end
+ return DECLINED
+ end
+
+ return OK, ctx
+end
+
+
+function _M.connect_upstream(session, ctx)
+ local conf = session.upstream_conf
+ local nodes = conf.nodes
+ if #nodes == 0 then
+ core.log.error("failed to connect: no nodes")
+ return DECLINED
+ end
+
+ local node = nodes[math_random(#nodes)]
+ local sk = sdk.connect_upstream(node, conf)
+ if not sk then
+ return DECLINED
+ end
Review Comment:
Would be better to have a retry logic here ?
A detailed error message is also required. The current one is not clear which node was accessed at the moment.
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