When a remote server is unavailable or very slow, some git commands can stall out indefinitely. It would be a very good thing if remote commands -- but especially git fetch -- could be given a timeout.
-hpa
threads / discuss / 35295
Request: timeout option for remote operations, esp. "git fetch"
Subject: Request: timeout option for remote operations, esp. "git fetch"
Re: Request: timeout option for remote operations, esp. "git fetch"
"H. Peter Anvin" <hpa@zytor.com> wrote:
> When a remote server is unavailable or very slow, some git commands can > stall out indefinitely. It would be a very good thing if remote > commands -- but especially git fetch -- could be given a timeout.
We've had SO_KEEPALIVE on git and ssh transports since e47a8583 (2011-12-06) SO_KEEPALIVE for http was added recently (a15d069a) and will be in git 1.8.5
Do you want a shorter timeout for slow (but still alive) servers?
Re: Request: timeout option for remote operations, esp. "git fetch"
On 11/10/2013 12:17 PM, Eric Wong wrote:
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> "H. Peter Anvin" <hpa@zytor.com> wrote: >> When a remote server is unavailable or very slow, some git commands can >> stall out indefinitely. It would be a very good thing if remote >> commands -- but especially git fetch -- could be given a timeout. > > We've had SO_KEEPALIVE on git and ssh transports since e47a8583 (2011-12-06) > SO_KEEPALIVE for http was added recently (a15d069a) and will be in git 1.8.5 > > Do you want a shorter timeout for slow (but still alive) servers? >
Yes; note that SO_KEEPALIVE only guarantees that the server is alive at the TCP socket level. If the server is overloaded but technically alive it may still make no meaningful forward progress.
-hpa
Junio C HamanoRe: Request: timeout option for remote operations, esp. "git fetch"
"H. Peter Anvin" <hpa@zytor.com> writes:
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> On 11/10/2013 12:17 PM, Eric Wong wrote: >> "H. Peter Anvin" <hpa@zytor.com> wrote: >>> When a remote server is unavailable or very slow, some git commands can >>> stall out indefinitely. It would be a very good thing if remote >>> commands -- but especially git fetch -- could be given a timeout. >> >> We've had SO_KEEPALIVE on git and ssh transports since e47a8583 (2011-12-06) >> SO_KEEPALIVE for http was added recently (a15d069a) and will be in git 1.8.5 >> >> Do you want a shorter timeout for slow (but still alive) servers? >> > > Yes; note that SO_KEEPALIVE only guarantees that the server is alive at > the TCP socket level. If the server is overloaded but technically alive > it may still make no meaningful forward progress.
Which means that your original wish may not be granted with SO_KEEPALIVE at all, no? I was wondering if you wanted a forced timeout based on alarm(2), something similar to what you added to git-daemon in 960deccb (git-daemon: timeout, eliminate double DWIM, 2005-10-19).
Re: Request: timeout option for remote operations, esp. "git fetch"
On 11/12/2013 09:45 AM, Junio C Hamano wrote:
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> "H. Peter Anvin" <hpa@zytor.com> writes: > >> On 11/10/2013 12:17 PM, Eric Wong wrote: >>> "H. Peter Anvin" <hpa@zytor.com> wrote: >>>> When a remote server is unavailable or very slow, some git commands can >>>> stall out indefinitely. It would be a very good thing if remote >>>> commands -- but especially git fetch -- could be given a timeout. >>> >>> We've had SO_KEEPALIVE on git and ssh transports since e47a8583 (2011-12-06) >>> SO_KEEPALIVE for http was added recently (a15d069a) and will be in git 1.8.5 >>> >>> Do you want a shorter timeout for slow (but still alive) servers? >>> >> >> Yes; note that SO_KEEPALIVE only guarantees that the server is alive at >> the TCP socket level. If the server is overloaded but technically alive >> it may still make no meaningful forward progress. > > Which means that your original wish may not be granted with > SO_KEEPALIVE at all, no? I was wondering if you wanted a forced > timeout based on alarm(2), something similar to what you added to > git-daemon in 960deccb (git-daemon: timeout, eliminate double DWIM, > 2005-10-19). >
Yes, something more like that on the client end. SO_KEEPALIVE is better than nothing, but not really good enough.
-hpa
Jeff KingRe: Request: timeout option for remote operations, esp. "git fetch"
On Tue, Nov 12, 2013 at 10:33:49AM -0800, H. Peter Anvin wrote:
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> > Which means that your original wish may not be granted with > > SO_KEEPALIVE at all, no? I was wondering if you wanted a forced > > timeout based on alarm(2), something similar to what you added to > > git-daemon in 960deccb (git-daemon: timeout, eliminate double DWIM, > > 2005-10-19). > > > > Yes, something more like that on the client end. SO_KEEPALIVE is better > than nothing, but not really good enough.
Would it be enough to just use timeout(1), like:
timeout 10m git fetch
That will time the _whole_ fetch operation, which means a legitimately gigantic but fast fetch would still fail. Setting a shorter timeout only for periods of inactivity on the network socket would catch killed or very laggy connections. But it would not catch a server that feeds you data at a constant but ridiculously slow rate.
-Peff