LUA: parse multi-line variable and cut needed string - nginx

I have next nginx location with Lua code (used with nginx lua-resty-redis):
location = /healthcheck {
content_by_lua_block {
local red = redis:new()
used_mem_limit = 536870912
-- connect to redis
ok, err = red:connect(ngx.var.redis_host, 6379)
if not ok then
ngx.log(ngx.ERR, "Redis connection error: ", err)
ngx.status = 500
return
end
-- setting connection timeout
red:set_timeout(1000)
-- getting redis used_memory_rss
memory = red:info('memory')
red_used_memory = ...
-- set response code
if (red_used_memory >= used_mem_limit) then
http_code = 500
elseif (red_used_memory < used_mem_limit)
http_code = 200
else
http_code = 500
end
ngx.status = http_code
}
}
memory variable should be like this:
# Memory
used_memory:105157968
used_memory_human:100.29M
used_memory_rss:110387200
used_memory_rss_human:105.27M
used_memory_peak:105219456
used_memory_peak_human:100.35M
used_memory_peak_perc:99.94%
used_memory_overhead:32290608
used_memory_startup:487168
used_memory_dataset:72867360
used_memory_dataset_perc:69.62%
total_system_memory:1044770816
I need to get used_memory_rss value, so then I can compare it with used_mem_limit. So, I don't know, how to complete red_used_memory = ... line.

There seems to be only digits in possible value so use a simple regexp and then convert resulting string to number:
red_used_memory = tonumber(memory:match('used_memory_rss:(%d+)'))
Line breaks are irrelevant.

Related

ValueError: invalid literal for int() with base 10: 'Oompa Loompa\x07\x08'

I have the TCP server set up for receiving messages from connected clients, but when the message contains packed hex e.g "Oompa Loompa\x07\x08" it shows me this error:
ValueError: invalid literal for int() with base 10: 'Oompa Loompa\x07\x08'
I guess I have decoding issue in the code but I don't know how to fix it.
import socket
import threading
HEADER = 64
PORT = 5050
SERVER = "192.168.1.103"
ADDR = (SERVER, PORT)
FORMAT = 'utf-8'
DISCONNECT_MESSAGE = "!DISCONNECT"
server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.bind(ADDR)
def handle_client(conn, addr):
print(f"[NEW CONNECTION] {addr} connected.")
connected = True
while connected:
msg_length = conn.recv(HEADER).decode(FORMAT)
if msg_length:
msg_length = int(msg_length)
msg = conn.recv(msg_length).decode(FORMAT)
if msg == DISCONNECT_MESSAGE:
connected = False
print(f"[{addr}] {msg}")
conn.send("Msg received".encode(FORMAT))
conn.close()
def start():
server.listen()
print(f"[LISTENING] Server is listening on {SERVER}")
while True:
conn, addr = server.accept()
thread = threading.Thread(target=handle_client, args=(conn, addr))
thread.start()
print(f"[Active Clients] {threading.active_count() - 1}")
print("[BOOTING] server is starting...")
start()
It seems like hex is a strings and needs to be an int. Try sending that message in binary.

NGINX LUA Content-Length +1 Byte Lost

I am having an interesting bug and method issue
Lua mentions that the js_content variable has a length of 80 bytes.
But when I don't use the "Content-Length" header, firefox mentions that 81 bytes of data are transferred.
I don't know where the +1 byte excess comes from
I will be glad if you can help, an application I wrote with VBNet gives an error when I noticed that the "Content-Length" header is 80 bytes while parsing json data from my remote server, but it works fine when I add +1.
local ref_array = {1, 2, 3}
local sArray = {}
sArray["1"] = "One"
sArray["2"] = "Two"
sArray["3"] = "Tree"
local ctable = {}
for index, data in ipairs(ref_array) do
if sArray[tostring(data)] ~= nil then
local cinfo = {}
cinfo["X"] = tostring(data)
cinfo["Y"] = sArray[tostring(data)]
cinfo["Z"] = 0
table.insert(ctable, cinfo)
end
end
local js_content = cjson.encode(ctable)
ngx.header['Content-Type'] = 'application/json'
ngx.header['Content-Length'] = #js_content -- 80 byte
ngx.say(js_content)
ngx.exit(200)
I guess the problem is the Line Feed Character character at the end.
ngx.say always adds linefeed
ngx.print is just output
problem solved
Linefeed Character

Strange io.popen behaviour in lua

I have lua block in nginx config, which checks for redis-server connection and if 4 java-processes are up, and then returns 200 or 500 status accordingly to this checks.
location = /healthcheck {
content_by_lua_block {
local redis = require "resty.redis"
local red = redis:new()
red:set_timeout(1000)
local ok, err = red:connect("127.0.0.1", 6379)
if not ok then
ngx.status = 500
return
end
local ps = io.popen("/bin/ps aux |grep -c '[j]ava.*63'")
local output = tostring(ps:read('*a'))
ps:close()
if string.match(output, '4') then
ngx.status = 200
else
ngx.status = 500
end
}
}
But periodically output variable takes nil value, while it shouldn't. Just can't get why it happens.
Thanks in advance, comrades.
UPD:
Using tonumber fails on
bad argument #2 to 'tonumber' (number expected, got string)
Updated location config:
location = /healthcheck {
content_by_lua_block {
local redis = require "resty.redis"
local red = redis:new()
red:set_timeout(1000)
local ok, err = red:connect("127.0.0.1", 6379)
if not ok then
ngx.status = 500
return
end
local ps = io.popen("/bin/ps aux |grep -c '[j]ava.*63'")
local output = tonumber(ps:read())
ps:close()
if (output == 4) then
ngx.status = 200
else
ngx.status = 500
end
}
}
UPD2:
Logging to nginx error (with tostring) prints next:
grep: write error: Broken pipe
2016/04/19 17:54:48 [error] 301#0: *5 [lua] content_by_lua(healthcheck.conf:33):20: OUTPUT:nil
UPD3:
Using command grep -c '[j]ava.*63' <(/bin/ps aux) to avoid the use of pipe:
local ps = io.popen("grep -c '[j]ava.*63' <(/bin/ps aux)")
getting next error:
sh: -c: line 0: syntax error near unexpected token `('
sh: -c: line 0: `grep -c '[j]ava.*63' <(/bin/ps aux)'
According to this answer and some testing next config do the job:
location = /healthcheck {
content_by_lua_block {
local redis = require "resty.redis"
local red = redis:new()
red:set_timeout(1000)
local ok, err = red:connect("127.0.0.1", 6379)
if not ok then
ngx.status = 500
return
end
local ps = io.popen("/bin/ps aux >/tmp/ps.out", "w")
ps:close()
local ps = io.popen("grep -c '[j]ava.*63' /tmp/ps.out")
local output = tostring(ps:read())
ps:close()
if string.match(output, '4') then
ngx.status = 200
else
ngx.status = 500
end
}
}

lua with Nginx : bad argument to 'getNewSessionID' (string expected, got nil)

I have compiled nginx with Lua. and i am facing a problem .
When i hit localhost i get an error in nginx error logs
2015/05/29 07:41:32 [error] 112#0: *1 lua entry thread aborted: runtime error: /opt/hello.lua:11: bad argument #1 to 'getNewSessionID' (string expected, got nil)
stack traceback:
coroutine 0:
[C]: in function 'getNewSessionID'
Nginx configurations are
location / {
default_type 'text/html';
content_by_lua_file /opt/hello.lua;
}
And my hello.lua look like
package.path = package.path ..';/opt/?.lua'
JSON = (loadfile "/opt/JSON.lua")()
local proxyFunctions = require("proxyCode")
coherenceNGIXLocation = "/coherence"
local coherenceCookie = proxyFunctions.getExistingSessionID()
-- To Create a coherance Session if not present
if (not coherenceCookie or coherenceCookie == '') then
-- ngx.log(ngx.INFO,"No Coherence Session Exists, Creating New")
local uidCookieValueEncoded = proxyFunctions.base64Encode(str,proxyFunctions.getNewSessionID())
local sessCreateResponse = proxyFunctions.coherencePut('{"sessionToken":"'..uidCookieValueEncoded..'"}')
local parsedJSON= JSON:decode(sessCreateResponse.body)
ngx.log(ngx.INFO, "Coherence Session Create")
ngx.log(ngx.INFO, "\n\n\n=============Coherence Res==============\n\n\n"..sessCreateResponse.body.."\n\n\n=============Coherence Res==============\n\n\n")
end
local client_cookie = ngx.req.get_headers()["cookie"]
-- To Create a coherance Session if not present
ngx.log(ngx.DEBUG, "\n\n\n=============REQ==============\n\n\n"..proxyFunctions.deepPrint(ngx.req.get_headers()).."\n\n\n=============REQ==============\n\n\n")
-- Set the cookie for the legacy request
ngx.req.set_header('cookie', client_cookie)
ngx.log(ngx.INFO, "\n\n\n=============REQ URI==============\n\n\n"..ngx.var.request_uri.."\n\n\n=============REQ URI==============\n\n\n")
local legacy_res = ngx.location.capture("/app"..ngx.var.request_uri, { share_all_vars = true })
ngx.log(ngx.DEBUG, "\n\n\n=============APP Res==============\n\n\n"..proxyFunctions.deepPrint(legacy_res.header).."\n\n\n=============APP Res==============\n\n\n")
if (legacy_res.status == 302) then
ngx.redirect(legacy_res.header.Location )
else
ngx.log(ngx.INFO, "Passing the Page/Layout to Maken")
local dev_res_encoded = legacy_res.body
dev_res_encoded = ngx.escape_uri(dev_res_encoded)
-- ngx.req.set_header('Cookie', ngx.req.get_headers()["cookie"])
-- ngx.req.set_header("Content-Type", "text/html") -- application/x-www-form-urlencoded -- 'page='..dev_res_encoded
ngx.req.set_header('cookie', client_cookie) -- maken/render
-- legacy_res.header('Content-Length', legacy_res.header['Content-Length']);
local maken_res = ngx.location.capture("/maken/", {method = ngx.HTTP_POST, body = legacy_res.body, share_all_vars = true} )
ngx.header['Set-Cookie'] = legacy_res.header["Set-Cookie"]
ngx.log(ngx.INFO, "Sending Back Maken Response to Client/Browser with Cookies from lagacy")
ngx.say(maken_res.body)
end
My proxyCode.lua looks like
function _M.getNewSessionID()
-- strip the sessionID length 11 cookie name before putting into the session
-- return string.sub(ngx.var.uid_set,11)
return _M.removeCookieSessionPrefixname(ngx.var.uid_set,11)
end
function _M.removeCookieSessionPrefixname(cookieName)
return string.sub(cookieName,11)
end
function _M.getIncomingAuthToken()
local cookie = ngx.req.get_headers()["Cookie"]
if (cookie ~=nil) then
local str = string.match(cookie,"AuthToken=(.*)$")
if (str ~= nil) then
return string.sub(str,11)
end
end
return nil
end
Can someone help me why i am getting this error ? i am new to Lua programming. and trying to run legacy application on my laptop.

Nginx + LUA, how to output file?

Having trouble with file output in Nginx + Lua. I chosen LUA, because nginx logic is pretty complicated, based on referrer or subdomains, etc.
Having request like /img/am1/s/1.jpg I need to check if file exists in /somepath/am1/1.jpg. If it exists, then output it, otherwise proxy request to backend.
Ok, found it
content_by_lua '
local file = "/path..."
local f = io.open(file, "rb")
local content = f:read("*all")
f:close()
ngx.print(content)
';
If someone need to know how to output last n lines from file:
location /service-man/log {
default_type 'text/plain';
content_by_lua '
local log_path = "/path/to/log.log"
-- Opens a file in read
file = io.open(log_path, "r")
if file==nil
then
ngx.say(log_path .. " can\'t read or does not exists")
return
end
-- sets the default input file
io.input(file)
local lines = {}
-- read the lines in table lines
for line in io.lines() do
table.insert(lines, line)
end
io.close(file)
log_limit = 10
if #lines < log_limit then
log_start = 0
else
log_len = #lines
log_start = log_len - log_limit
end
local one_line = ""
for i, line in ipairs(lines) do
if i > log_start then
one_line = one_line .. line .. "\\n"
end
end
ngx.say(one_line)
';
}
Should be compatible with nginx/1.6.2 and Lua 5.3.
Please share if you know how to make it in more optimal way.

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