I'm working on a test scenario that it's testing a socket server over TCP with JMeter.
My test tree and TCP Sampler looks like this:
I used BinaryTCPClientImpl for 'TCPClient classname'. It worked correctly and sent the hex packet (24240011093583349040005000F6C80D0A) to the server and I received the packet in server side too. After receiving the packet in the server side, it answered and JMeter received the response packet correctly too.
As you can see in the following test result, the TCP Sampler (Login Packet) send 4 times in the right way and responses are true (404000120935833490400040000105490d0a).
The problem is that JMeter waits till the end of Timeout (in my case 2000ms) for each request and when it occurred then go to the next request. I don't want to wait for a timeout, I need a forward scenario, without the wait.
I found the solution according to the following question and it helped me:
Answer link
I just set the End of line(EOL) byte value to 10 that it means return new line in ASCI table.
Related
I have a trouble to tune TCP client-server communication.
My current project has a client, running on PC (C#) and a server,
running on embedded Linux 4.1.22-ltsi.
Them use UDP communication to exchanging data.
The client and server work in blocking mode and
send short messages one to 2nd
(16, 60, 200 bytes etc.) that include either command or set of parameters.
The messages do note include any header with message length because
UDP is message oriented protocol. Its recvfrom() API returns number of received bytes.
For my server's program structure is important to get and process entire alone message.
The problem is raised when I try to implement TCP communication type instead of UDP.
The server's receive buffer (recv() TCP API) is 2048 bytes:
#define UDP_RX_BUF_SIZE 2048
numbytes = recv(fd_connect, rx_buffer, UDP_RX_BUF_SIZE, MSG_WAITALL/*BLOCKING_MODE*/);
So, the recv() API returns from waiting when rx_buffer is full, i.e after it receives
2048 bytes. It breaks all program approach. In other words, when client send 16 bytes command
to server and waits an answer from it, server's recv() keeps the message
"in stomach", until it will receive 2048 bytes.
I tried to fix it as below, without success:
On client side (C#) I set the socket parameter theSocket.NoDelay.
When I checked this on the sniffer I saw that client sends messages "as I want",
with requested length.
On server side I set TCP_NODELAY socket option to 1
int optval= 1;
setsockopt(fd,IPPROTO_TCP, TCP_NODELAY, &optval, sizeof(optval);
On server side (Linux) I checked socket options SO_SNDLOWAT/SO_RCVLOWAT and they are 1 byte each one.
Please see the attached sniffer's log picture. 10.0.0.10 is a client. 10.0.0.106 is a server. It is seen, that client activates PSH flag (push), informing the server side to move the incoming data to application immediately and do not fill a buffer.
Additional question: what is SSH encrypted packets that runs between the sides. I suppose that it is my Eclipse debugger on PC (running server application through the same Ethernet connection) sends them. Am I right?
So, my problem is how to cause `recv() API to return each short message (16, 60, 200 bytes etc.) instead of accumulating them until receiving buffer fills.
TCP is connection oriented and it also maintains the order in which packets are sent and received.
Having said that, in TCP client, you will receive the stream of bytes and not the individual udp message as in UDP. So you will need to send the packet length and marker as the initial bytes.
So client can first find the packet length and then read data till packet length is reached and then expect new packet length.
You can also check for library like netty, zmq to do this extra work
For c send function(blocking way) it's specified what function returns with size of sent bytes when it's received on destinations. I'm not sure that I understand all nuances, also after writing "demo" app with WSAIoctl and WSARecv on server side.
When send returns with less bytes number than asked in buffer-length parameter?
What is considered as "received on destinations"? My first guess it's when it sit on server's OS buffer and server application is notified. My second one it's when server application recv call have read it fully?
Unless you are using a (somewhat exotic) library, a send on a socket will return the number of bytes passed to the TCP buffer successfully, not the number of bytes received by the peer (see Microsoft´s docs for example).
When you are streaming data via a socket, you need to check the bytes effectively accepted into the TCP send buffer. That´s why usually a send command is inside a loop that will issue several sends if needed.
Errors in send are local: for example if the socket is closed by the peer during a sending operation (making your socket invalid) or if the operation times out (TCP buffer not emptying, i. e. peer not receiving data fast enough or some other trouble).
After all send is completed you have no easy way of knowing if the peer received all the bytes you sent. You´ll usually just issue closesocket and make sure that your socket has a proper linger option set (i. e. only close after timeout or sucessfully finishing the send). Alternatively you wait for a confirmation by the peer (for example via a recv that returns zero bytes, indicating that the connection was gracefully closed).
Edit: typo
I've just recently started using JMeter.
I'm trying to run a TCP sampler on one of my servers.
The TCP sampler is set to all default values, with my IP, port number and text to send.
The server receives the text and responds as expected.
However, once JMeter receives the response it doesn't close the connection; it just waits until I stop the test manually, at which point the server logs show the client has disconnected.
I also have a response assertion which looks for this string:
{"SERVER":[{"End":200}]}\r\n
The Assertion is set to apply to main sample and sub-samples, the response field to test is set to Text Response.
With the pattern matching rules set to Equals I get:
Device Server Sampler
Device Server Response Assertion : Test failed: text expected to equal /
****** received : {"SERVER":[{"End":200}]}[[[
]]]
****** comparison: {"SERVER":[{"End":200}]}[[[\r\n]]]
/
If I set pattern matching to Contains I get:
Device Server Sampler
Which I can only assume at this point is a pass??
But no matter how I try it JMeter never closes the socket, so when I stop the tests myself and View the results in a table the status is marked as Warning, even though the correct amount of bytes have been received, and the data is correct.
JMeter doesn't seem to like \r\n so I've run the same tests removing those from the strings on both sides, but the sockets still remain open until I stop the tests.
Got any ideas what the issue may be?
In the TCP Sampler I needed to set End of line(EOL) byte value to 10, which is the decimal byte value for \n
I am make a application base on lwip,the applcation just send data to the server;
When my app works for some times (about 5 hours),I found that the send thread hung in send() function,and after about 30min send() return 0,and my thread run agin;
In the server side ,have make a keepalive,its time is 5min,when my app hungs,5min later the server close the sockect,but my app have not get this,still hungs in send() until 30min get 0 return; why this happen?
1: the up speed is not enough to send data,it will hungs in send?
2: maybe the server have not read data on time,and it make send buff full and hungs?
how can i avoid these peoblems in my code ? I have try to set TCP_NODELAY,SO_SNDTIMEO and select before send,but also have this problem.
send() blocks when the receiver is too far behind the sender. recv() returns zero when the peer has closed the connection, which means you must close the socket and stop reading.
I'm trying to run a simple test with TCP Sampler
When using default TCPClient class, after the response timeout time passes, I receive a correct response from the server, and then Error 500 in sampler results:
Response code: 500 Response message:
org.apache.jmeter.protocol.tcp.sampler.ReadException:
It seems like that JMeter does not recognize end of message characters (the server sends \r\n).
How can I configure JMeter to see the EOM?
I tried to use BinaryTCPClientImpl, and set tcp.BinaryTCPClient.eomByte = 13 in Jmeter.properties, but binaryTCPClient expects HEX data, while I send human readable string, and it still ignores the eomByte...
Any ideas?
Found the problem.
Those server did not sent \r\n in several cases.
Everything started working after the server was fixed.
I came accross the same behaviour and examined the offered responses (sending \r\n at the end of the message in the server side \ setting the eol byte value option in the gui) but it didn't work for me.
My solution: Following this question I found that \0 is the eol character Jmeter expects in TCP sampler. when my server terminates the messages with \0 - the message is receieved in Jmeter.
Some more references: Jmeter documentation (TCPClientImpl chapter - that's where the tcp.eolByte is discussed).
Some option: if the size of the messages is constant, one can examine LengthPrefixedBinaryTCPClientImpl (see this discussion).
Anyone give me a solution for this error. Why I m getting 500 response code why jmeter throwing the read exception and what is the solution for this error if I already received my success response.
TCP Sampler will not return until EOF is received.
Set your own EOF byte value at TCP Sampler.
The server sends a stream at the end of EOF byte value.