Re: [PATCH v2] app/testpmd: show output of commands read from file

[Ferruh Yigit <ferruh.yigit@amd.com>]

On 8/22/2024 11:41 AM, Bruce Richardson wrote:
> Testpmd supports the "--cmdline-file" parameter to read a set of initial
> commands from a file. However, the only indication that this has been
> done successfully on startup is a single-line message, no output from
> the commands is seen.
> 

For user I think it makes sense to see the command [1], only concern is
if someone parsing testpmd output may be impacted on this, although I
expect it should be trivial to update the relevant parsing.

[1]
Btw, I can still see the command output, I assume because command does
the printf itself, for example for 'show port summary 0' command:
- before patch:
...
Number of available ports: 2
Port MAC Address       Name         Driver         Status   Link
0    xx:xx:xx:xx:xx:xx xxxx:xx:xx.x aaaaaaaa       up       xxx Gbps
...

- after patch
...
testpmd> show port summary 0
Number of available ports: 2
Port MAC Address       Name         Driver         Status   Link
0    xx:xx:xx:xx:xx:xx xxxx:xx:xx.x aaaaaaaa       up       xxx Gbps
...

Only difference above is, after patch the command itself also printed.


> To improve usability here, we can use cmdline_new rather than
> cmdline_file_new and have the output from the various commands sent to
> stdout, allowing the user to see better what is happening.
> 
> Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
> 
> ---
> v2: use STDOUT_FILENO in place of hard-coded "1"
> ---
>  app/test-pmd/cmdline.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/app/test-pmd/cmdline.c b/app/test-pmd/cmdline.c
> index b7759e38a8..52e64430d9 100644
> --- a/app/test-pmd/cmdline.c
> +++ b/app/test-pmd/cmdline.c
> @@ -6,6 +6,7 @@
>  #include <ctype.h>
>  #include <stdarg.h>
>  #include <errno.h>
> +#include <fcntl.h>
>  #include <stdio.h>
>  #include <stdint.h>
>  #include <stdlib.h>
> @@ -13431,7 +13432,18 @@ cmdline_read_from_file(const char *filename)
>  {
>  	struct cmdline *cl;
>  
> -	cl = cmdline_file_new(main_ctx, "testpmd> ", filename);
> +	/* cmdline_file_new does not produce any output which is not ideal here.
> +	 * Much better to show output of the commands, so we open filename directly
> +	 * and then pass that to cmdline_new with stdout as the output path.
> +	 */
> +	int fd = open(filename, O_RDONLY);
> +	if (fd < 0) {
> +		fprintf(stderr, "Failed to open file %s: %s\n",
> +			filename, strerror(errno));
> +		return;
> +	}
> +
> +	cl = cmdline_new(main_ctx, "testpmd> ", fd, STDOUT_FILENO);
>

Above is almost save as 'cmdline_file_new()' function with only
difference that it uses '-1' for 's_out'.

If this usecase may be required by others, do you think does it have a
value to pass 's_out' to 'cmdline_file_new()' or have a new version of
API that accepts 's_out' as parameter?

btw, I recognized that 'cmdline' library doesn't have doxygen
documentation, which is a gap to address. Next time when someone asks
for entry level task, we can point this one.