[pbs-devel] applied: [RFC PATCH proxmox-backup] tools/async_io: do not error on Accept for StaticIncoming
Wolfgang Bumiller
w.bumiller at proxmox.com
Mon Apr 12 15:55:15 CEST 2021
applied
On Thu, Apr 08, 2021 at 02:28:20PM +0200, Dominik Csapak wrote:
> in proxmox-backup-proxy, we log and discard any errors on 'accept',
> so that we can continue to server requests
>
> in proxmox-backup-api, we just have the StaticIncoming that accepts,
> which will forward any errors from the underlying TcpListener
>
> this patch also logs and discards the errors, like in the proxy.
> Otherwise it could happen that if the api-daemon has more files open
> than the proxy, it will shut itself down because of a
> 'too many open files' error if there are many open connections
>
> (the service should also restart on exit i think, but this is
> a separate issue)
>
> Signed-off-by: Dominik Csapak <d.csapak at proxmox.com>
> ---
> two remaining issues/questions:
>
> 1. maybe we want an accept loop in proxmox-backup-api akin to the one
> in the proxy? this way we have better locality of the error logging,
> more control of e.g. how many connections we accept, etc.
>
> 2. is it wise to log every failed connection attempt? i can very easily
> generate massive logspam with a single line of 'ab'. shouldn't we
> e.g. only log once a second how many connections were not accepted?
> this is for the api as well as the proxy
>
> src/tools/async_io.rs | 14 ++++++++++----
> 1 file changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/src/tools/async_io.rs b/src/tools/async_io.rs
> index 997c02fa..844afaa9 100644
> --- a/src/tools/async_io.rs
> +++ b/src/tools/async_io.rs
> @@ -6,6 +6,7 @@ use std::pin::Pin;
> use std::task::{Context, Poll};
>
> use futures::stream::{Stream, TryStream};
> +use futures::ready;
> use tokio::io::{AsyncRead, AsyncWrite, ReadBuf};
> use tokio::net::TcpListener;
> use hyper::client::connect::Connection;
> @@ -108,10 +109,15 @@ impl hyper::server::accept::Accept for StaticIncoming {
> self: Pin<&mut Self>,
> cx: &mut Context,
> ) -> Poll<Option<Result<Self::Conn, Self::Error>>> {
> - match self.get_mut().0.poll_accept(cx) {
> - Poll::Pending => Poll::Pending,
> - Poll::Ready(Ok((conn, _addr))) => Poll::Ready(Some(Ok(conn))),
> - Poll::Ready(Err(err)) => Poll::Ready(Some(Err(err))),
> + let this = self.get_mut();
> + loop {
> + match ready!(this.0.poll_accept(cx)) {
> + Ok((conn, _addr)) => return Poll::Ready(Some(Ok(conn))),
> + Err(err) => {
> + eprintln!("error accepting connection: {}", err);
> + continue;
> + }
> + }
> }
> }
> }
> --
> 2.20.1
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