How to address slow running tools? feat. cspell

[unphased]

I'm playing with cspell, and I found that it does work out of the box:

[DEBUG Tue 28 Mar 2023 12:41:58 PM EDT] ...y/null-ls.nvim/lua/null-ls/helpers/generator_factory.lua:320: spawning command "cspell" at /home/slu/InsightCamera with args { "--show-suggestions", "lint", "--language-id", "yaml", "stdin" }
[TRACE Tue 28 Mar 2023 12:41:59 PM EDT] ...y/null-ls.nvim/lua/null-ls/helpers/generator_factory.lua:204: error output: 
1/1 ./stdin: 1109.93ms X
CSpell: Files checked: 1, Issues found: 33 in 1 files

[TRACE Tue 28 Mar 2023 12:41:59 PM EDT] ...y/null-ls.nvim/lua/null-ls/helpers/generator_factory.lua:205: output: /home/slu/InsightCamera:25:71 - Unknown word (CCACHE) Suggestions: [CACHE, COACHED, COACHER, COACHES, COACH]
/home/slu/InsightCamera:27:51 - Unknown word (tegra) Suggestions: [terra, tetra, Terra, tergal, tear]
...

but in most of my code projects, it runs out its allotted 5s timeout:

[DEBUG Tue 28 Mar 2023 11:49:10 AM EDT] ...y/null-ls.nvim/lua/null-ls/helpers/generator_factory.lua:320: spawning command "cspell" at /home/slu/.vim with args { "--show-suggestions", "lint", "--language-id", "lua", "stdin" }
[TRACE Tue 28 Mar 2023 11:49:10 AM EDT] .../.local/share/nvim/lazy/null-ls.nvim/lua/null-ls/rpc.lua:127: received LSP notification for method textDocument/didOpen
[TRACE Tue 28 Mar 2023 11:49:10 AM EDT] .../share/nvim/lazy/null-ls.nvim/lua/null-ls/generators.lua:21: running generators for method NULL_LS_DIAGNOSTICS_ON_OPEN
[DEBUG Tue 28 Mar 2023 11:49:10 AM EDT] ...y/null-ls.nvim/lua/null-ls/helpers/generator_factory.lua:320: spawning command "cspell" at /home/slu/.vim with args { "--show-suggestions", "lint", "--language-id", "lua", "stdin" }
[TRACE Tue 28 Mar 2023 11:49:10 AM EDT] .../.local/share/nvim/lazy/null-ls.nvim/lua/null-ls/rpc.lua:127: received LSP notification for method textDocument/didOpen
[TRACE Tue 28 Mar 2023 11:49:10 AM EDT] .../share/nvim/lazy/null-ls.nvim/lua/null-ls/generators.lua:21: running generators for method NULL_LS_DIAGNOSTICS_ON_OPEN
[DEBUG Tue 28 Mar 2023 11:49:10 AM EDT] ...y/null-ls.nvim/lua/null-ls/helpers/generator_factory.lua:320: spawning command "cspell" at /home/slu/.vim with args { "--show-suggestions", "lint", "--language-id", "lua", "stdin" }
[TRACE Tue 28 Mar 2023 11:49:10 AM EDT] .../.local/share/nvim/lazy/null-ls.nvim/lua/null-ls/rpc.lua:127: received LSP notification for method textDocument/didOpen
[TRACE Tue 28 Mar 2023 11:49:10 AM EDT] .../share/nvim/lazy/null-ls.nvim/lua/null-ls/generators.lua:21: running generators for method NULL_LS_DIAGNOSTICS_ON_OPEN
[DEBUG Tue 28 Mar 2023 11:49:10 AM EDT] ...y/null-ls.nvim/lua/null-ls/helpers/generator_factory.lua:320: spawning command "cspell" at /home/slu/.vim with args { "--show-suggestions", "lint", "--language-id", "lua", "stdin" }
[TRACE Tue 28 Mar 2023 11:49:10 AM EDT] .../.local/share/nvim/lazy/null-ls.nvim/lua/null-ls/rpc.lua:127: received LSP notification for method textDocument/didOpen
[TRACE Tue 28 Mar 2023 11:49:10 AM EDT] .../share/nvim/lazy/null-ls.nvim/lua/null-ls/generators.lua:21: running generators for method NULL_LS_DIAGNOSTICS_ON_OPEN
[DEBUG Tue 28 Mar 2023 11:49:10 AM EDT] ...y/null-ls.nvim/lua/null-ls/helpers/generator_factory.lua:320: spawning command "cspell" at /home/slu/.vim with args { "--show-suggestions", "lint", "--language-id", "lua", "stdin" }
[TRACE Tue 28 Mar 2023 11:49:10 AM EDT] .../.local/share/nvim/lazy/null-ls.nvim/lua/null-ls/rpc.lua:127: received LSP notification for method textDocument/didOpen
[TRACE Tue 28 Mar 2023 11:49:10 AM EDT] .../share/nvim/lazy/null-ls.nvim/lua/null-ls/generators.lua:21: running generators for method NULL_LS_DIAGNOSTICS_ON_OPEN
[DEBUG Tue 28 Mar 2023 11:49:10 AM EDT] ...y/null-ls.nvim/lua/null-ls/helpers/generator_factory.lua:320: spawning command "cspell" at /home/slu/.vim with args { "--show-suggestions", "lint", "--language-id", "lua", "stdin" }
[TRACE Tue 28 Mar 2023 11:49:10 AM EDT] .../.local/share/nvim/lazy/null-ls.nvim/lua/null-ls/rpc.lua:127: received LSP notification for method textDocument/didOpen
[TRACE Tue 28 Mar 2023 11:49:10 AM EDT] .../share/nvim/lazy/null-ls.nvim/lua/null-ls/generators.lua:21: running generators for method NULL_LS_DIAGNOSTICS_ON_OPEN
[DEBUG Tue 28 Mar 2023 11:49:10 AM EDT] ...y/null-ls.nvim/lua/null-ls/helpers/generator_factory.lua:320: spawning command "cspell" at /home/slu/.vim with args { "--show-suggestions", "lint", "--language-id", "lua", "stdin" }
[TRACE Tue 28 Mar 2023 11:49:10 AM EDT] .../.local/share/nvim/lazy/null-ls.nvim/lua/null-ls/rpc.lua:127: received LSP notification for method textDocument/didOpen
[TRACE Tue 28 Mar 2023 11:49:10 AM EDT] .../share/nvim/lazy/null-ls.nvim/lua/null-ls/generators.lua:21: running generators for method NULL_LS_DIAGNOSTICS_ON_OPEN
[DEBUG Tue 28 Mar 2023 11:49:10 AM EDT] ...y/null-ls.nvim/lua/null-ls/helpers/generator_factory.lua:320: spawning command "cspell" at /home/slu/.vim with args { "--show-suggestions", "lint", "--language-id", "lua", "stdin" }
[TRACE Tue 28 Mar 2023 11:49:10 AM EDT] .../.local/share/nvim/lazy/null-ls.nvim/lua/null-ls/rpc.lua:127: received LSP notification for method textDocument/didOpen
[TRACE Tue 28 Mar 2023 11:49:10 AM EDT] .../share/nvim/lazy/null-ls.nvim/lua/null-ls/generators.lua:21: running generators for method NULL_LS_DIAGNOSTICS_ON_OPEN
[DEBUG Tue 28 Mar 2023 11:49:10 AM EDT] ...y/null-ls.nvim/lua/null-ls/helpers/generator_factory.lua:320: spawning command "cspell" at /home/slu/.vim with args { "--show-suggestions", "lint", "--language-id", "lua", "stdin" }
[DEBUG Tue 28 Mar 2023 11:49:15 AM EDT] ....local/share/nvim/lazy/null-ls.nvim/lua/null-ls/loop.lua:170: command cspell timed out after 5000 ms
[DEBUG Tue 28 Mar 2023 11:49:15 AM EDT] ....local/share/nvim/lazy/null-ls.nvim/lua/null-ls/loop.lua:170: command cspell timed out after 5000 ms
[DEBUG Tue 28 Mar 2023 11:49:15 AM EDT] ....local/share/nvim/lazy/null-ls.nvim/lua/null-ls/loop.lua:170: command cspell timed out after 5000 ms
[DEBUG Tue 28 Mar 2023 11:49:15 AM EDT] ....local/share/nvim/lazy/null-ls.nvim/lua/null-ls/loop.lua:170: command cspell timed out after 5000 ms
[DEBUG Tue 28 Mar 2023 11:49:15 AM EDT] ....local/share/nvim/lazy/null-ls.nvim/lua/null-ls/loop.lua:170: command cspell timed out after 5000 ms
[DEBUG Tue 28 Mar 2023 11:49:15 AM EDT] ....local/share/nvim/lazy/null-ls.nvim/lua/null-ls/loop.lua:170: command cspell timed out after 5000 ms
[DEBUG Tue 28 Mar 2023 11:49:15 AM EDT] ....local/share/nvim/lazy/null-ls.nvim/lua/null-ls/loop.lua:170: command cspell timed out after 5000 ms
[DEBUG Tue 28 Mar 2023 11:49:15 AM EDT] ....local/share/nvim/lazy/null-ls.nvim/lua/null-ls/loop.lua:170: command cspell timed out after 5000 ms
[DEBUG Tue 28 Mar 2023 11:49:15 AM EDT] ....local/share/nvim/lazy/null-ls.nvim/lua/null-ls/loop.lua:170: command cspell timed out after 5000 ms

This is unsurprising given that cspell took an entire second to process just a single 183-line yaml file; cspell clearly needs some optimization, but until that happens, I'm interested in knowing what the correct approach would be to at least change this thing to call cspell on individual code files. Given the observed performance it's probably going to use too much cpu to justify on my macbook but I can use it on my server machine.

Questions

• How to extend the timeout in null-ls config for a given program?
• How can I ensure only one process is run? I can see in my logs the lua one attempted to run 8 processes concurrently and this is a poor use of resources
• How to implement heuristics that will "give up" on running on a given file after it fails to meet the timeout deadline a few times? I don't want a whole CPU core (or 8) consumed constantly whenever I'm editing some file that is just too big for it to complete running within the timeout.
• I can only assume that trying to hack-change the call to only run on the file being edited may change the output format and break things... what's the approach here? So i looked at it again once I noticed it did run on my plugins.lua file but definitely cannot make the deadline on my init.lua file, yes it is already running on a per-file basis not on each file in a dir, since the command call does specify stdin there. OK

CSpell is the first tool i've encountered that brings these questions to the forefront, but these questions apply equally to all tools that have long runtimes.

[unphased]

thought about it some more and i think at least the use of an option (which i'm sure exists, I just have to find it) to make the linter only run on file save also helps address poorly performing linters. So I dunno... If this was an issue I would just close this before someone else closes it for me at this point. But it's a discussion so I'll leave it open for input since I welcome that in all forms.

[jose-elias-alvarez]

You can check the documentation for instructions on how to configure source-specific timeouts as well as how to make diagnostic sources run only on save.

As for the multiple processes issue: I describe the cause and a potential fix in #596. Because of the way that null-ls works, I doubt slow sources like this will ever provide an ideal experience, but there are some improvements to be made if someone is willing to push them through.