Porcelain doesn't seem to close stdin

[ivan]

Maybe I'm missing something, but all of these calls hang forever here (Erlang 19.3, Elixir master, Ubuntu 16.04.2):

Porcelain.exec("cat", [], in: "")
Porcelain.exec("cat", [], in: "hello\n")
Porcelain.exec("python", ["-c", "import sys; print sys.stdin.read()"], in: "")
Porcelain.exec("python", ["-c", "import sys; print sys.stdin.read()"], in: "hello\n")

I am guessing this happens because Porcelain doesn't close stdin on the spawned process. Do I need to do something special, or is this a bug?

I am using the basic driver, not the goon driver.

[ivan]

Oh, maybe a duplicate of #23.

[ivan]

"the exec function does not work with programs that read all input until EOF before producing any output. Such programs will hang since Erlang ports don’t provide any mechanism to indicate the end of input." https://hexdocs.pm/porcelain/Porcelain.Driver.Basic.html

[ivan]

As a workaround, I figured out that if I just needed to send a single line to a subprocess waiting for EOF, instead of doing:

Porcelain.exec("wg", ["pubkey"], in: (privkey |> Base.encode64) <> "\n")

I could do:

Porcelain.exec("bash", ["-c", "head -n 1 | wg pubkey"], in: (privkey |> Base.encode64) <> "\n")