How to prevent errno 32 broken pipe?

Question

Your server process has received a SIGPIPE writing to a socket. This usually happens when you write to a socket fully closed on the other (client) side. This might be happening when a client program doesn't wait till all the data from the server is received and simply closes a socket (using close function).

In a C program you would normally try setting to ignore SIGPIPE signal or setting a dummy signal handler for it. In this case a simple error will be returned when writing to a closed socket. In your case a python seems to throw an exception that can be handled as a premature disconnect of the client.

The broken pipe error usually occurs if your request is blocked or takes too long and after request-side timeout, it'll close the connection and then, when the respond-side (server) tries to write to the socket, it will throw a pipe broken error.

It depends on how you tested it, and possibly on differences in the TCP stack implementation of the personal computer and the server.

For example, if your sendall always completes immediately (or very quickly) on the personal computer, the connection may simply never have broken during sending. This is very likely if your browser is running on the same machine (since there is no real network latency).

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In general, you just need to handle the case where a client disconnects before you're finished, by handling the exception.

Remember that TCP communications are asynchronous, but this is much more obvious on physically remote connections than on local ones, so conditions like this can be hard to reproduce on a local workstation. Specifically, loopback connections on a single machine are often almost synchronous.

This might be because you are using two method for inserting data into database and this cause the site to slow down.

def add_subscriber(request, email=None):
    if request.method == 'POST':
        email = request.POST['email_field']
        e = Subscriber.objects.create(email=email).save()  <==== 
        return HttpResponseRedirect('/')
    else:
        return HttpResponseRedirect('/')

In above function, the error is where arrow is pointing. The correct implementation is below:

def add_subscriber(request, email=None):
    if request.method == 'POST':
        email = request.POST['email_field']
        e = Subscriber.objects.create(email=email)
        return HttpResponseRedirect('/')
    else:
        return HttpResponseRedirect('/')

If it's a python a web application or service such as Flask or FastAPI, this error might occur if the production server is configured to timeout a request that takes too long. There are relevant parameters in Gunicorn and Uvicorn such as GRACEFUL_TIMEOUT and TIMEOUT that need to be configured according to the needs of your application. You may also want to check your reverse proxy or gateway timeout thresholds.