Multiprocess tracking issue #28722

1. 
   ryanofsky commented at 6:22 pm on October 24, 2023: contributor

   This issue will be updated to reflect the current state of bitcoin core multiprocess support.

   PRs for review related to building & releasing:

   • #31375
   • #31679
   • #31802
   • Upstream libmultiprocess pulls

   PRs for review related to mining:

   • #30437

   PRs for review related wallet & gui:

   • #29409
   • #10102
   • #19460
   • #19461

   Issues:

   • #30983
   • #31098
   • #31109
     • caused by #31003
     • resolved by #31283
   • #31756

   PRs / issues closed:

   • #10242
   • #10295
   • #10600
   • #10244
   • #10605
   • #14636
   • #14437
   • #14711
   • #15342
   • #15373
   • #15288
   • #15531
   • #10973
   • #16839
   • #17906
   • #18278
   • #16367
   • #17999
   • #18743
   • #18587
   • #18677
   • #20494
   • #20046
   • #21035
   • #21732
   • #19160
   • #22216
   • #22214
   • #22218
   • bitcoin-core/gui#360
   • #22215
   • #22217
   • #19101
   • #22848
   • #22219
   • #23003
   • #23006
   • #23004
   • #23005
   • #23499
   • #28721
   • #28907
   • #28978
   • #28921
   • #28929
   • #30509
   • #30510
   • #31196
   • #31197
   • #30940
   • #30955
   • #31105
   • #31003
   • #31288
   • #31480
   • #31318
   • #31196
   • #31740
   • #31151
   • #31455
   • #31763
   • #31815
   • #31945
   • #31283
   • #31827
   • #31564
   • #31992
   • #31741
   • #30975
   • #31785

   Links:

   • Documentation
   • Project board
   • Wiki
   • Presentation (code shown)
   • Working group
   • List of working groups
2. fanquake referenced this in commit 29c2c90362 on Nov 13, 2023
3. fanquake referenced this in commit a238356823 on Nov 22, 2023
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5. achow101 referenced this in commit 2f218c664b on Jan 23, 2024
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17. 
    sipa commented at 5:52 pm on April 15, 2025: member

    Please let me know if this is already implemented, being discussed elsewhere, or if this is not the right place for it.

    Would it make sense to (not now, or even necessarily in the short term), make bitcoin-cli (or bitcoin rpc, with the wrapper binary) support IPC communication with bitcoin-node, which would gain an “RPC-over-IPC” service? Since IPC supports communication over a UNIX socket, and there has been discussion about what would be needed to make RPC support UNIX sockets, this seems like an easy way to achieve the same thing.

    This cannot be a replacement for the TCP/IP-based RPC functionality, as it would lack authentication control, but enable an easy, efficient, configuration-free way of executing RPC commands?

18. 
    ryanofsky commented at 7:21 pm on April 15, 2025: contributor

    re: #28722 (comment)

    This is an interesting idea. Another place to discuss it might be #5029, depending on what goal of the change is. There are links to different unix socket implementations in #5029, and according to #31194, supporting unix socket RPC calls is a top reason for wanting to drop the dependency on libevent (which is done in #32061).

    Probably the cleanest way to support RPCs over a unix socket would be to send JSON-RPC requests directly over the socket as discussed in the previous issues. But it would be pretty easy to implement a new IPC interface similar to the IPC mining interface which could allow bitcoin-cli or another client to make RPC method calls over the IPC socket. I could make a small PR to implement that if it would be interesting. The interface could be as simple as something like:

    0interface Rpc $Proxy.wrap("interfaces::Rpc") {
    1    callMethod [@0](/bitcoin-bitcoin/contributor/0/) (context :Proxy.Context, request :Text) -> (result :Text);
    2};
    

    if it just passes JSON requests and responses. Though probably the interface should be more structured and use separate fields for things like wallet names and user names.

    there has been discussion about what would be needed to make RPC support UNIX sockets, this seems like an easy way to achieve the same thing.

    Yes, this should be easier to implement than other approaches. The relative downsides are that it would be more internally complicated, and more awkward to write external clients for, since it would require capnproto.

Contributors
ryanofsky sipa