Re: [PATCH 00/10] [RFC] Simple IPC Mechanism

On Tue, Jan 12 2021, Jeff Hostetler via GitGitGadget wrote:

This series introduces a multi-threaded IPC mechanism called "Simple IPC".
This is a library-layer feature to make it easy to create very long running
daemon/service applications and for unrelated Git commands to communicate
with them. Communication uses pkt-line messaging over a Windows named pipe
or Unix domain socket.

On the server side, Simple IPC implements a (platform-specific) connection
listener and worker thread-pool to accept and handle a series of client
connections. The server functionality is completely hidden behind the
ipc_server_run() and ipc_server_run_async() APIs. The daemon/service
application only needs to define an application-specific callback to handle
client requests.

Note that Simple IPC is completely unrelated to the long running process
feature (described in sub-process.h) where the lifetime of a "sub-process"
child is bound to that of the invoking parent process and communication
occurs over the child's stdin/stdout.

Simple IPC will serve as a basis for a future builtin FSMonitor daemon
feature.

I only skimmed this so far. In the past we had a git-read-cache--daemon
-> git-index-helper[1] -> watchman. The last iteration of that seems to
be the [3] re-roll from Ben Peart in 2017. I used/tested that for a
while and had some near-production use-cases of it.

How does this new series relate to that past work (if at all), and (not
having re-read the old threads) were there reasons those old patch
serieses weren't merged in that are addressed here, mitigated etc?

1. https://lore.kernel.org/git/1402406665-27988-1-git-send-email-pclouds@gmail.com/ (local)
2. https://lore.kernel.org/git/1457548582-28302-1-git-send-email-dturner@twopensource.com/ (local)
3. https://lore.kernel.org/git/20170518201333.13088-1-benpeart@microsoft.com/ (local)
4. https://lore.kernel.org/git/87bmhfwmqa.fsf@evledraar.gmail.com/ (local)