vtysh input requires TTY, but I want to drive it from a pipe

[Chris Ward]

I want to drive vtysh ( the shell which interprets bgp commands ) from another process, with its stdin and stdout connected via pipes. When I try this on 'master', I get an error message to the effect that stdin is not a TTY, and my bgp commands are not run.

What would it take to fix this ? I am willing to do some amount of coding.

[Chris Ward]

I have coded an initial implementation of this and made a PR https://github.com/Azure/sonic-frr/pull/21 . I'm currently awaiting my manager to give me permission to sign the CLA; also it will take a while for me to attempt to build this as I think I need to build the whole of SONiC. 

Feedback as to the acceptability of the patch would be appreciated.

[Masaru OKI]

I use vtysh -c command -c command ... or vtysh -f file instead.

2021年10月26日(火) 18:24 Chris Ward <tjc...@gmail.com>:

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[Chris Ward]

I can't use the '-c' form because I am trying to run vtysh as a coroutine (handling commands received from a web server). Does 'vtysh -f -' read commands from stdin ? My look at the source code suggested that '-f' was for reading a configuration file rather than for reading commands.

[Chris Ward]

It looks as if vtysh doesn't currently handle 'vtysh -f -' to mean read stdin as a stream, but the code looks as if it could be fairly easily adapted to do that. Would that be a better patch than the one I proposed in the PR ?

[Chris Ward]

I have a new proposed PR, https://github.com/Azure/sonic-frr/pull/22 , which works by interpreting 'vtysh -f -' as a request to read stdin (which can be a pipe or a file redirection). Comments appreciated !