JarCastingNetCrusher for Java
NetCrusher is TCP/UDP proxy framework for Java and a command line tool that could be placed in the middle between any client and server and allows to check both sides for failover.
- emulates network failures
- emulates frozen connection
- supports both TCP and UDP
- supports multiple dynamic connections through the same proxy tunnel
- allows to check the state of connections
- allows to filter/dump data
- supports throttling (delay and/or throughput control)
- garbage-less buffering
- high performance (16.6 Gbits on loopback interface of my laptop)
- supports IP4/IP6
NetCrusher is build on top of Java 8 NIO and has no external dependencies except SLF4J.
Read documentation.
Download latest dist.tar.gz to get the command line tool.
TCP
NioReactor reactor = new NioReactor();
TcpCrusher crusher = TcpCrusherBuilder.builder()
.withReactor(reactor)
.withBindAddress("localhost", 10080)
.withConnectAddress("google.com", 80)
.buildAndOpen();
// ... some actions
// emulate reconnect
crusher.reopen();
// ... check the client connection is reestablished successfully
// closing
crusher.close();
reactor.close();
UDP
NioReactor reactor = new NioReactor();
DatagramCrusher crusher = DatagramCrusherBuilder.builder()
.withReactor(reactor)
.withBindAddress("localhost", 10188)
.withConnectAddress("time-nw.nist.gov", 37)
.buildAndOpen();
// ... some actions
// check data is sent
Assert.assertTrue(crusher.getInner().getReadDatagramMeter().getTotal() > 0);
// closing
crusher.close();
reactor.close();
Additional samples
Checks additional samples in the project root folder:
Command line
For manual QA the command-line wrapper is available both for TCP and Datagram mode
$ ./run-tcp-crusher.sh 127.0.0.1:12345 google.com:80
# Version: 0.8
# Print `HELP` for the list of the commands
# enter the command in the next line
CLOSE
[20:19:20.586] INFO TcpCrusher </127.0.0.1:12345>-<google.com/64.233.161.101:80> is closed
[20:19:20.586] INFO Crusher is closed
# enter the command in the next line
OPEN
[20:19:21.655] INFO TcpCrusher </127.0.0.1:12345>-<google.com/64.233.161.101:80> is open
[20:19:21.655] INFO Crusher is open
More about the command line mode in wiki.
Maven
<dependency>
<groupId>com.github.netcrusherorg</groupId>
<artifactId>netcrusher-core</artifactId>
<version>0.10</version>
</dependency>
Performance
See wiki page
License
Apache License Version 2.0, http://www.apache.org/licenses/LICENSE-2.0.html
Links to the similar projects
- Jepsen - Distributed Systems Safety Analysis
- Java-NIO-TCP-Proxy - Simple TCP proxy
- netem - Linux kernel module allows to distort network facilities
- socat - bridges everything with everything
