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POProblems communicating between Node.js and Python via stdio
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copied!<p>I'm spawning a Node process from within a Python thread and passing data between them via stdio. After Python sends something to Node, Node fires up a child process and then sends the output from that child process back to Python.</p> <p>This works, for a few seconds and then no more data comes. However, if I kill the Node process, then suddenly all of the data comes at once.</p> <p>I figure this is something to do with buffering but I've tried so many things and can't get it to work properly.</p> <p>It's worth mentioning that if I run the monitor outside of Python it works fine, so this is probably something on the Python side.</p> <p>Relevant Python code:</p> <pre><code>class MonitorThread(Thread): # *snip* def run(self): self.process = Popen(['node', path.join(PACKAGE_PATH 'monitor.js')], stdout=PIPE, stdin=PIPE, stderr=PIPE) while self.process.poll() is None: stdout = self.process.stdout.readline().rstrip('\n') if stdout: main_thread(debug, stdout) stderr = self.process.stderr.readline().rstrip('\n') if stderr: main_thread(debug, stderr) #time.sleep(0.1) </code></pre> <p>Relevant Node.js code (in CoffeeScript but even if you don't know it you get the idea):</p> <pre><code># *snip* child = spawn cmd, options child.stdout.on 'data', (data) -> process.stdout.write "stdout: #{data.toString().trim()}\n" child.stderr.on 'data', (data) -> process.stdout.write "stderr: #{data.toString().trim()}\n" </code></pre> <p>There's a lot of other code but it's not really relevant, data is being sent and then afterwards data is being received, just only for a moment. It IS still running as when I kill it manually, the rest of the data suddenly appears.</p> <pre><code>Monitor [send] - {"wrap": false, "directories": {"src": "lib"}, "id": 0, "base_dir": "C:\\Users\\Joe\\Documents\\GitHub\\CoffeeScript-Sublime-Plugin"} Monitor [recv] - 13:55:30 - compiled src\a.coffee Monitor [recv] - path.exists is now called `fs.exists`. Monitor [recv] - 13:55:30 - compiled src\b.coffee </code></pre> <ul> <li>I've tried util.pump()</li> <li>I've tried, with the spawn() call, stdio: 'inherit'</li> <li>I've tried waiting for the 'drain' event before sending more data.</li> </ul>

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