I am using Ratchet Socket. I have established a new server connection and I want to stop server from running. In this scenario I have IP(Hostname) and port with me, So how can I stop that?
Is it possible to make a server connection that never ends?
When I make a server connection, first day the data output is perfect from DB, But on second day, the error is generated as "Connection is closed by foreign host". But still I can connect to that port.
Code
<?php
use Ratchet\Server\IoServer;
use MyApp\Chat;
use React\EventLoop\Factory;
use React\ZMQ\Context;
require dirname(__DIR__) . '/vendor/autoload.php';
require dirname(__DIR__) . '/src/MyApp/Chat.php';
$server = IoServer::factory(
new Chat(),
6666
);
$server->run();
?>
1.
I am using Ratchet Socket. I have established a new server connection
and I want to stop server from running. In this scenario I have
IP(Hostname) and port with me, So how can I stop that?
I assume that you currently run your Ratchet server by running it as a php script in a terminal window or screen.
eg: php push-server.php
Once you stop running the script your server will stop.
2.
Is it possible to make a server connection that never ends?
Yes, if your php script stops working from the terminal, you have to manually restart it. Its better to use a program like Supervisor (A Process Control System) which is recommended by Ratchet.
Check this link for more info http://supervisord.org/installing.html
The supervisord service will monitor your php script and will automatically restart it if it crashes which is suited for production environments.
3.
When I make a server connection, first day the data output is perfect
from DB, But on second day, the error is generated as "Connection is
closed by foreign host". But still I can connect to that port.
This is quite common and I've noticed it too. It usually happens when the server is heavily loaded or times out. Your JavaScript should check for this message and re-initiate a new connection if you see this message. You can also get it to try again after a random timer as well.
Edits
Also the __construct method for the Ratchet\Server\IoServer requires 3 prams, of which the 3rd one being optional. The first and second need to be objects of MessageComponentInterface and ServerInterface.
public function __construct(MessageComponentInterface $app, ServerInterface $socket, LoopInterface $loop = null) {
The way you instantiate the IoServer seems incorrect.
Related
I was doing a very basic test using node.js, latest orientjs and latest OrientDB:
open server (using port 2424)
assign db (server.use)
server.list()
If I do this, the promise at server.list() hangs and the server shows the error "Impossible to read a chunk of length...". But if I just don't assign the db, it works fine. Also, if I call db functions (like db.record.get) instead of server.list(), that works fine too.
Is it the case that you can't call a server function after calling server.use?
On a related point, is there a way to set a network timeout for orientjs? If I try to do any of this and the target server is not reachable, it just hangs on opening the server and/or assigning the database.
Once a Login script is executed with few user, I don't see connection reset problem, whereas, when the same is run 100 users, "java.net.SocketException: Connection reset" starts throwing for very first link.
What I don't understand is if there is connection problem, then it should even show the same error for single or few users as well.
This means that your server is rejecting connections because it is either overloaded or misconfigured.
It is regular that you don't face it with 1 user and face it with 100, this is typically what load testing brings, ie simulate traffic on your server
It might be the case described in Connection Reset since JMeter 2.10 ? wiki page.
If you are absolutely sure that your server is not overloaded and is configured to accept 100+ connections (defaults are good for development, not for production, they need to be tweaked) you can try work it around as follows:
In user.properties file add the next 2 lines:
httpclient4.retrycount=1
hc.parameters.file=hc.parameters
In hc.parameters file add the following line:
http.connection.stalecheck$Boolean=true
Both files live in JMeter's bin folder.
You need to restart JMeter to pick the properties up.
Above instructions are applicable for HttpClient4 implementation, make sure you use it, the fastest and the easiest way to set HttpClient4 implementation for all the HTTP Request samplers is using HTTP Request Defaults
I have a server that runs Postgresql. in the logs I am seeing this message for my resque based 'worker' box, multiple times a minute. Some minutes there isn't a message, others could be 10 times.
2016-01-12 13:40:36 EST:1.1.8.2(33899):[16141]: LOG: could not receive data from client: Connection reset by peer
Now when i go into the 1.1.8.2 box to look at netstat -ntp i don't see a port 33899, and most of them are at least in the 40xxx range by now. That may be conjecture but I'm at a loss to find out why a Redis/Resque/Puma Rails stack would be printing out these messages, let alone what that means even if i get to the bottom of it.
Will I gain memory back if they are closed 'normally'?
Is this a thing to be wary of?
How does one debug OLD ports that are open when the db box and the worker box both don't display the ports any more?
This message is probably due to the resque worker task not closing the database connection before it exits. It's not a huge problem, but presumably Postgres is doing a little extra work to clean it up, and it makes a mess of your log file...
One solution is to add a hook to your resque worker's task file (the same file that contains the self.perform definition):
def self.after_perform(*args)
ActiveRecord::Base.connection.disconnect!
end
This is a question to an earlier question I had posted it turn out I need to generalize it. So I have these commands:
tracker=tcpip('127.0.0.1', 20200, 'NetworkRole', 'server');
fopen(tracker);
system('"C:\PROGRA~1\..." param1 param2')
I am using the same computer to be a listening server and a client as communication of an external device to the computer. The issue is the tracker server is waiting for the client to be started (system command).
Any feedback? Thanks
It is not possible to do it in a single script. The function fopen(tracker) will always wait for a connection. This is because it is supposed that the following instructions will be executed for a client.
Your code is saying: "Wait until a new connection is stablished (fopen). Then create a new client (system)". This doesn't make sense, so you should execute the client from a different script or program.
You can check it in the Matlab information: http://www.mathworks.es/es/help/instrument/using-tcpip-server-sockets.html
As you can see they specifically say:
MATLAB Client: This code is running on a second copy of MATLAB.
I am on an embedded platform (mipsel architecture, Linux 2.6 kernel) where I need to monitor IPC between two closed-source processes (router firmware) in order to react to a certain event (dynamic IP change because of DSL reconnect). What I found out so far via strace is that whenever the IP changes, the DSL daemon writes a special message into a UNIX domain socket bound to a specific file name. The message is consumed by another daemon.
Now here is my requirement: I want to monitor the data flow through that specific UNIX domain socket and trigger an event (call a shell script) if a certain message is detected. I tried to monitor the file name with inotify, but it does not work on socket files. I know I could run strace all the time, filtering its output and react to changes in the filtered log file, but that would be too heavy a solution because strace really slows down the system. I also know I could just poll for the IP address change via cron, but I want a watchdog, not a polling solution. And I am interested in finding out whether there is a tool which can specifically monitor UNIX domain sockets and react to specific messages flowing through in a predefined direction. I imagine something similar to inotifywait, i.e. the tool should wait for a certain event, then exit, so I can react to the event and loop back into starting the tool again, waiting for the next event of the same type.
Is there any existing Linux tool capable of doing that? Or is there some simple C code for a stand-alone binary which I could compile on my platform (uClibc, not glibc)? I am not a C expert, but capable of running a makefile. Using a binary from the shell is no problem, I know enough about shell programming.
It has been a while since I was dealing with this topic and did not actually get around to testing what an acquaintance of mine, Denys Vlasenko, maintainer of Busybox, proposed as a solution to me several months ago. Because I just checked my account here on StackOverflow and saw the question again, let me share his insights with you. Maybe it is helpful for somebody:
One relatively easy hack I can propose is to do the following:
I assume that you have a running server app which opened a Unix domain listening socket (say, /tmp/some.socket), and client programs connect to it and talk to the server.
rename /tmp/some.socket -> /tmp/some.socket1
create a new socket /tmp/some.socket
listen on it for new client connections
for every such connection, open another connection to /tmp/some.socket1 to original server process
pump data (client<->server) over resulting pairs of sockets (code to do so is very similar to what telnetd server does) until EOF from either side.
While you are pumping data, it's easy to look at it, to save it, and even to modify it if you need to.
The downside is that this sniffer program needs to be restarted every time the original server program is restarted.
This is similar to what Celada also answered. Thanks to him as well! Denys's answer was a bit more concrete, though.
I asked back:
This sounds hacky, yes, because of the restart necessity, but feasible.
Me not being a C programmer, I keep wondering though if you know a
command line tool which could do the pass-through and protocolling or
event-based triggering work for me. I have one guy from our project in
mind who could hack a little C binary for that, but I am unsure if he
likes to do it. If there is something pre-fab, I would prefer it. Can it
even be done with a (combination of) BusyBox applet(s), maybe?
Denys answered again:
You need to build busybox with CONFIG_FEATURE_UNIX_LOCAL=y.
Run the following as intercepting server:
busybox tcpsvd -vvvE local:/tmp/socket 0 ./script.sh
Where script.sh is a simple passthrough connection
to the "original server":
#!/bin/sh
busybox nc -o /tmp/hexdump.$$ local:/tmp/socket1 0
As an example, I added hex logging to file (-o FILE option).
Test it by running an emulated "original server":
busybox tcpsvd -vvvE local:/tmp/socket1 0 sh -c 'echo PID:$$'
and by connecting to "intercepting server":
echo Hello world | busybox nc local:/tmp/socket 0
You should see "PID:19094" message and have a new /tmp/hexdump.19093 file
with the dumped data. Both tcpsvd processes should print some log too
(they are run with -vvv verbosity).
If you need more complex processing, replace nc invocation in script.sh
with a custom program.
I don't think there is anything that will let you cleanly sniff UNIX socket traffic. Here are some options:
Arrange for the sender process to connect to a different socket where you are listening. Also connect to the original socket as a client. On receipt of data, notice the data you want to notice and also pass everything along to the original socket.
Monitor the system for IP address changes yourself using a netlink socket (RTM_NEWADDR, RTM_NEWLINK, etc...).
Run ip monitor as an external process and take action when it writes messages about added & removed IP addresses on its standard output.