proposal: net: context variants for udp functions

[milkpirate]

net/udpsock: exposes contexts for several UDP related functions:

In the udpsock package are several (exposed) functions (see below) which use context.Background() as context for calls to unexposed internal functions.

• ResolveUDPAddr
• DialUDP
• ListenUDP
• ListenMulticastUDP

I propose to expose the contexts to the user. See PR #59880. This makes it possible for the user to hand over its own context and allows hin/her to e.g. cancel or timeout the named UDP actions.

The PR does not change the API for the existing functions above, it just adds another function for each of them with the suffix WithContext and an additional argument (namely the context ctx). This would add the following functions:

• ResolveUDPAddrWithContext
• DialUDPWithContext
• ListenUDPWithContext
• ListenMulticastUDPWithContext

With the same signature but a context.Conteext added as first argument. Internally the "non-context" function from above, are then just wrappers for the WithContext functions and call them with context.Background().

[seankhliao]

cc @ianlancetaylor @neild

[ianlancetaylor]

This is largely a dup of #49097, which is a proposal that has been accepted but not yet implemented.

[gopherbot]

Change https://go.dev/cl/490975 mentions this issue: net: context aware network Dialer.Dial functions

[milkpirate]

@ianlancetaylor
Kinda, at least for DialUDP.

And to be honest, I like my version better (who would have seen that comming?😄), since its:

• less invasive
• better to comprehend (since the different functions (with and without context) are closer to each other)
• so its better to maintain

How do we go forward? Shall I adapt my PR to make context available to other methods/functions in https://go.dev/cl/490975 ?

[ianlancetaylor]

If you think #49097 is making a poor choice of API, then please comment on that issue.

For this issue I suggest that we first complete the work on #49097, then consider whether there is anything to do here.