Re: [RFC PATCH v2 1/1] devtools: add vscode configuration generator

["Burakov, Anatoly" <anatoly.burakov@intel.com>]

On 7/29/2024 4:30 PM, Bruce Richardson wrote:
> On Mon, Jul 29, 2024 at 02:05:52PM +0100, Anatoly Burakov wrote:
>> A lot of developers use Visual Studio Code as their primary IDE. This
>> script generates a configuration file for VSCode that sets up basic build
>> tasks, launch tasks, as well as C/C++ code analysis settings that will
>> take into account compile_commands.json that is automatically generated
>> by meson.
>>
>> Files generated by script:
>>   - .vscode/settings.json: stores variables needed by other files
>>   - .vscode/tasks.json: defines build tasks
>>   - .vscode/launch.json: defines launch tasks
>>   - .vscode/c_cpp_properties.json: defines code analysis settings
>>
>> The script uses a combination of globbing and meson file parsing to
>> discover available apps, examples, and drivers, and generates a
>> project-wide settings file, so that the user can later switch between
>> debug/release/etc. configurations while keeping their desired apps,
>> examples, and drivers, built by meson, and ensuring launch configurations
>> still work correctly whatever the configuration selected.
>>
>> This script uses whiptail as TUI, which is expected to be universally
>> available as it is shipped by default on most major distributions.
>> However, the script is also designed to be scriptable and can be run
>> without user interaction, and have its configuration supplied from
>> command-line arguments.
>>
>> Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
>> ---
>>
> Just was trying this out, nice script, thanks.

Thanks for the feedback! Comments below.

> 
> Initial thoughts concerning the build directory:
> - the script doesn't actually create the build directory, so there is no
>    guarantee that the build directory created will have the same parameters
>    as that specified in the script run. I'd suggest in the case where the
>    user runs the script and specifies build settings, that the build
>    directory is then configured using those settings.

I'm not sure I follow.

The script creates a command for VSCode to create a build directory 
using configuration the user has supplied at script's run time. The 
directory is not created by the script, that is the job of meson build 
system. This script is merely codifying commands for meson to do that, 
with the expectation that the user is familiar with VSCode workflow and 
will go straight to build commands anyway, and will pick one of them. 
Are you suggesting running `meson setup` right after?

Assuming we do that, it would actually then be possible to adjust launch 
tasks to only include *actual* built apps/examples (as well as infer 
things like platform, compiler etc.), as that's one weakness of my 
current "flying blind" approach, so I wouldn't be opposed to adding an 
extra step here, just want to make sure I understand what you're saying 
correctly.

> 
> - On the other hand, when the build directory already exists - I think the
>    script should pull all settings from there, rather than prompting the
>    user.
> 

That can be done, however, my own workflow has been that I do not ever 
keep build directories inside my source directory, so it would not be 
possible to pick up directories anywhere but the source directory.

I also think from the point of view of the script it would be easier to 
start from known quantities rather than guess what user was trying to do 
from current configuration, but I guess a few common-sense heuristics 
should suffice for most use cases, such as e.g. inferring debug builds.

> - I'm not sure I like the idea for reconfiguring of just removing the build
>    directory and doing a whole meson setup command all over again. This
>    seems excessive and also removes the possibility of the user having made
>    changes in config to the build dir without re-running the whole config
>    script. For example, having tweaked the LTO setting, or the
>    instruction_set_isa_setting. Rather than deleting it and running meson
>    setup, it would be better to use "meson configure" to adjust the one
>    required setting and let ninja figure out how to propagate that change.
>    That saves the script from having to track all meson parameters itself.

Last I checked, meson doesn't have a command that would "setup or 
configure existing" a directory, it's either "set up new one" or 
"configure existing one". I guess we could set up a fallback of 
"configure || setup".

> 
> - Finally, and semi-related, this script assumes that the user does
>    everything in a single build directory. Just something to consider, but
>    my own workflow till now has tended to keep multiple build directories
>    around, generally a "build" directory, which is either release or
>    debugoptimized type, and a separate "build-debug" directory + occasionally
>    others for build testing. When doing incremental builds, the time taken to
>    do two builds following a change is a lot less noticable than the time taken
>    for periodic switches of a single build directory between debug and release
>    mode.

The problem with that approach is the launch tasks, because a launch 
task can only ever point to one executable, so if you have multiple 
build directories, you'll have to have multiple launch tasks per 
app/example. I guess we can either tag them (e.g. "Launch dpdk-testpmd 
[debug]", "Launch dpdk-testpmd [asan]" etc.), or use some kind of 
indirection to "select active build configuration" (e.g. have one launch 
task but overwrite ${config:BUILDDIR} after request for configuration, 
so that launch tasks would pick up actual executable path at run time 
from settings). I would prefer the latter to be honest, as it's much 
easier to drop a script into ./vscode and run it together with 
"configure" command to switch between different build/launch 
configurations. What do you think?

> 
> Final thoughts on usability:
> 
> - Please don't write gdbsudo to /usr/local/bin without asking the user
>    first. Instead I think it should default to $HOME/.local/bin, but with a
>    prompt for the user to specify a path.

It's not creating anything, it's just printing out a snippet, which, if 
run by user, would do that - the implication is obviously that the user 
may correct it if necessary. The script actually picks up path to 
`gdbsudo` from `which` command, so if the user puts their command to 
$HOME/.local/bin or something, it would get picked up if it's in PATH. I 
see your point about maybe suggesting using a home directory path 
instead of a system wide path, I can change that.

> 
> - While I realise your primary concern here is an interactive script, I'd
>    tend towards requiring a cmdline arg to run in interactive mode and
>    instead printing the help usage when run without parameters. Just a
>    personal preference on my part though.

I found it to be much faster to pick my targets, apps etc. using a 
couple of interactive windows than to type out parameters I probably 
don't even remember ahead of time (especially build configurations!), 
and I believe it's more newbie-friendly that way, as I imagine very few 
people will want to learn arguments for yet-another-script just to start 
using VSCode. It would be my personal preference to leave it as 
default-to-TUI, but maybe recognizing a widely used `-i` parameter would 
be a good compromise for instant familiarity.

> 
> /Bruce

-- 
Thanks,
Anatoly