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Add CLI options for preopened listen sockets#3729

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sunfishcode merged 1 commit intobytecodealliance:mainfrom
haraldh:wasmtime_listen_cli
Feb 7, 2022
Merged

Add CLI options for preopened listen sockets#3729
sunfishcode merged 1 commit intobytecodealliance:mainfrom
haraldh:wasmtime_listen_cli

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@haraldh haraldh commented Jan 27, 2022 •
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As a follow up for #3711, this implements CLI options to insert pre-opened sockets.

--listenfd : Inherit environment variables and file descriptors following the systemd listen fd specification (UNIX only)

--tcplisten <SOCKET ADDRESS>: Grant access to the given TCP listen socket

TODO

  • Write test cases

EXAMPLES

$ git clone --branch wasi https://github.com/haraldh/mio.git
$ cd mio
$ cargo +nightly build --target wasm32-wasi --example tcp_server --features="os-poll net" 
$ wasmtime run --tcplisten 127.0.0.1:9000 --env 'LISTEN_FDS=1' target/wasm32-wasi/debug/examples/tcp_server.wasm 
Using preopened socket FD 3
You can connect to the server using `nc`:
 $ nc <IP> <PORT>
You'll see our welcome message and anything you type will be printed here.
^Z
[1]+  Stopped                 wasmtime run --tcplisten 127.0.0.1:9000 --env 'LISTEN_FDS=1' target/wasm32-wasi/debug/examples/tcp_server.wasm
$ bg
$ echo Hello | nc 127.0.0.1 9000
Accepted connection from: 0.0.0.0:0
Hello world!
Received data: Hello
Connection closed
$ fg
$ ^C

This was referenced Jan 27, 2022
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@github-actions github-actions bot added the wasi Issues pertaining to WASI label Jan 27, 2022
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@haraldh haraldh force-pushed the wasmtime_listen_cli branch 5 times, most recently from d921e8e to 6ba0c26 Compare January 28, 2022 13:56
@haraldh haraldh changed the title DRAFT: Add CLI options for preopened listen sockets Add CLI options for preopened listen sockets Jan 28, 2022
@haraldh haraldh force-pushed the wasmtime_listen_cli branch from 6ba0c26 to 877f4fb Compare February 1, 2022 07:46
@haraldh
wasmtime: add CLI options for pre-opened TCP listen sockets
6be5273 
This patch  implements CLI options to insert pre-opened sockets.

`--listenfd` : Inherit environment variables and file descriptors following
               the systemd listen fd specification (UNIX only).

`--tcplisten <SOCKET ADDRESS>`: Grant access to the given TCP listen socket.

Signed-off-by: Harald Hoyer <harald@profian.com>
@haraldh haraldh force-pushed the wasmtime_listen_cli branch from 877f4fb to 6be5273 Compare February 4, 2022 10:36
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haraldh commented Feb 4, 2022

rebased

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haraldh commented Feb 4, 2022 •
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added mio for wasi example to first comment

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sunfishcode commented Feb 7, 2022

This looks like it will be a good way to enable experimentation with the new WASI accept functionality.

Looking forward, the convention of having applications implicitly assume they can get environment variables like LISTEN_FDS is problematic for WASI. To make WASI programs modular and statically analyzable, we want to make API contracts explicit in imports and exports, rather than in dynamic environment-variable conventions. I expect what we'll want in the future is for this to use the Typed Main feature, and then to have WASI libc on the inside translate that back into making getenv("LISTEN_FDS") return this information for compatibility.

However, we can address that as the pieces needed to use Typed Main come online. For now, this looks good.

@sunfishcode sunfishcode merged commit fa889b4 into bytecodealliance:main Feb 7, 2022
mpardesh pushed a commit to avanhatt/wasmtime that referenced this pull request Mar 17, 2022
@haraldh @mpardesh
wasmtime: add CLI options for pre-opened TCP listen sockets (bytecode…
f81a663 
…alliance#3729)

This patch  implements CLI options to insert pre-opened sockets.

`--listenfd` : Inherit environment variables and file descriptors following
               the systemd listen fd specification (UNIX only).

`--tcplisten <SOCKET ADDRESS>`: Grant access to the given TCP listen socket.

Signed-off-by: Harald Hoyer <harald@profian.com>
@bjorn3 bjorn3 mentioned this pull request Sep 29, 2022
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@rvolosatovs rvolosatovs mentioned this pull request Jan 25, 2023
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