Hi Thierry, haproxy-list,
I've created another possibly interesting lua script, and it works :)
(mostly). (on my test machine..)
When i visit the 192.168.0.120:9003 website i always see the 'Hello
World' page. So in that regard this is usable, it is left to the browser
to send the request again, not sure how safe this is in regard to
mutations being send twice. It should probably check for POST requests
and then just return the error without replacing it with a redirect..
Not sure if that would catch all problem cases..
Ive created a lua service that counts how many requests are made, and
returns a error status every 5th request.
Second there is a lua response script that checks the status, and
replaces it by a redirect if it sees the faulty status 500.
This does currently result in the connection being closed and reopened
probably due to the txn.res:send().?.
Though i am still struggling with what is and isn't supposed to be possible.
For example the scripts below are running in 'mode http' and mostly just
changing 'headers'.
I expected to be able to simply read the status by calling
txn.f:status() but this always seems to result in 'null'.
Manually parsing the response buffer duplicate works but seems ugly..
txn.f:status() < it doesnt result in the actual status.
txn.res:set() < if used in place of send() causes 30 second delay
txn.done() < dumps core. (im not sure when ever to call it? the script
below seems to match the description that this function has.?.)
Am i trying to do it wrong?
p.s. Is 'health checking' using lua possible? The redis example looks
like a health 'ping'.. It could possibly be much much more flexible then
the tcp-check send / tcp-check expect routines..
I'm currently testing with HA-Proxy version 1.7-dev0-e4c4b7d and the
following configuration files:
#### haproxy.cfg ###
global
maxconn 6000
lua-load /var/etc/haproxy/luascript_lua-count5error
defaults
timeout connect 30000
timeout server 30000
timeout client 30000
mode http
log global
frontend TEST-lua-count
bind 192.168.0.120:9002
option http-keep-alive
http-request use-service lua.lua-count
frontend TEST-lua-retry-serverror
bind 192.168.0.120:9003
option http-keep-alive
http-request lua.retrystorerequest
http-response lua.retryerrors
default_backend hap_9002_http_ipvANY
backend hap_9002_http_ipvANY
mode http
retries 3
server 192.168.0.120_9002 192.168.0.120:9002
### luascript_lua-count5error ###
core.register_action("retryerrors" , { "http-res" }, function(txn)
local clientip = txn.f:src()
txn:Info(" LUA client " .. clientip)
local s = txn.f:status() -- doesnt work?
if s == null then
core.Info("LUA txn.s:status RETURNED: NULL, fallback needed ??")
local req = txn.res:dup()
local statusstr = string.sub(req, 10, 13)
s = tonumber(statusstr)
end
core.Info("LUA status " .. s)
if s ~= 200 then
txn:Info("LUA REDIRECT IT ! " .. s)
local url = txn:get_priv()
local response = ""
response = response .. "HTTP/1.1 302 Moved\r\n"
response = response .. "Location: " .. url .."\r\n"
response = response .. "\r\n"
txn.res:send(response)
--txn.res:set(response) -- causes 30 second delay..
--txn:done() --dumps core..
end
end);
core.register_action("retrystorerequest" , { "http-req" }, function(txn)
local url = txn.f:url()
txn:set_priv(url);
end);
core.register_service("lua-count", "http", function(applet)
if test == null then
test = 0
end
test = test + 1
local response = ""
if test % 5 == 0 then
applet:set_status(500)
response = "Error " .. test
else
applet:set_status(200)
response = "Hello World !" .. test
end
applet:add_header("content-length", string.len(response))
applet:add_header("content-type", "text/plain")
applet:start_response()
applet:send(response)
end)
