Linux - Named pipes - losing data - linux

Question

I am using named pipes for IPC. At times the data sent between the process can be large and frequent. During these time I see lots of data loss. Are there any obvious problems in the code below that could cause this?
Thanks
#!/usr/bin/env groovy
import java.io.FileOutputStream;
def bytes = new File('/etc/passwd').bytes
def pipe = new File('/home/mohadib/pipe')
1000.times{
def fos = new FileOutputStream(pipe)
fos.write(bytes)
fos.flush()
fos.close()
}
#!/usr/bin/env groovy
import java.io.FileInputStream;
import java.io.ByteArrayOutputStream;
def pipe = new File('/home/mohadib/pipe')
def bos = new ByteArrayOutputStream()
def len = -1
byte[] buff = new byte[8192]
def i = 0
while(true)
{
def fis = new FileInputStream(pipe)
while((len = fis.read(buff)) != -1) bos.write(buff, 0, len)
fis.close()
bos.reset()
i++
println i
}

Answer 1

Named pipes lose their contents when the last process closes them. In your example, this can happen if the writer process does another iteration while the reader process is about to do fis.close(). No error is reported in this case.
A possible fix is to arrange that the reader process never closes the fifo. To get rid of the EOF condition when the last writer disconnects, open the fifo for writing, close the read end, reopen the read end and close the temporary write end.

Answer 2

This section gives me worries:
1000.times{
def fos = new FileOutputStream(pipe)
fos.write(bytes)
fos.flush()
fos.close()
}
I know that the underlying Unix write() system call does not always write the requested number of bytes. You have to check the return value to see what number was actually written.
I checked the docs for Java and it appears fos.write() has no return value, it just throws an IOException if anything goes wrong. What does Groovy do with exceptions? Are there any exceptions happening?
If you can, run this under strace and view the results of the read and write system calls. It's possible that the Java VM isn't doing the right thing with the write() system call. I know this can happen because I caught glibc's fwrite implementation doing that (ignoring the return value) two years ago.