Whats the best way to stream the output?

[jasw]

Hi there,

The shell.exec interface can take a outputStream to get the returning response,

    int exec(String command, InputStream stdin,
        OutputStream stdout, OutputStream stderr) throws IOException;

I have used a few different OutputStream implementations trying to be able to read the output as the output comes in. I could easily pipe the output into input stream, but I found I could not read from input until the output is finished.

As an example, thinking if we are executing a long running or never ending command such as tail, of top, is there a way to be able to continuously feed the return?

I am thinking from a reactive programming point of view, if Jcabi can provide an API to do call backs for every line of response available.

If there are alternatives, please let me know.

Many thanks,
Jason

[jasw]

It turns out once I use the piped in/out stream with another thread, I could get 'live' streaming response back.

Just post my example here in case some one else needs it

       PipedOutputStream out = new PipedOutputStream();
        PipedInputStream in = new PipedInputStream(out);
        Thread thread = new Thread(() -> {
            try {
                shell.exec(command, new NullInputStream(0L), out, new NullOutputStream());
            } catch (IOException e) {
                log.error("command has failed",e);
            }

        });
        thread.start();
        Reader reader = new InputStreamReader(in);
        //rxjava-string makes this easier. 
        StringObservable.byLine(StringObservable.from(reader)).forEach(s -> log.info(s));

You can close this issue now.
Thanks,
Jason

[dmarkov]

@yegor256 take a look at this issue please and dispatch it somehow, see par.21

[yegor256]

@jasw thanks for submitting it and your example. please, close the issue (you're the author, it's better if you do it). thanks!

[0crat]

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