From be77b8ea1709b10f7747c9e1aa5b970921dac09d Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?J=C3=B6rg=20Thalheim?= Date: Sat, 8 Jan 2022 10:58:47 +0100 Subject: [PATCH] README: fix spelling/style --- README.md | 39 +++++++++++++++++++++++---------------- 1 file changed, 23 insertions(+), 16 deletions(-) diff --git a/README.md b/README.md index 6afc861..9dcbf9a 100644 --- a/README.md +++ b/README.md @@ -1,19 +1,20 @@ # nix-eval-jobs -This project evaluates nix attributes sets in parallel with a streamable json output. -This is useful for time and memory-intensive evaluations such as nixos machines i.e. in a CI context. -Evaluation happens with a controlable number of threads that are restarted if -their memory consumption grows beyond a threshold. +This project evaluates nix attributes sets in parallel with streamable json +output. This is useful for time and memory intensive evaluations such as NixOS +machines, i.e. in a CI context. The evaluation is done with a controllable +number of threads that are restarted when their memory consumption exceeds a +certain threshold. -For ease of integration nix-eval-jobs creates garbage collection roots for each -evaluated derivation (drv file not the build) inside the supplied attribute. -This prevent race conditions between nix garbage collection service and nix -builds processes started by the user. +To facilitate integration, nix-eval-jobs creates garbage collection roots for +each evaluated derivation (drv file, not the build) within the provided +attribute. This prevents race conditions between the nix garbage collection +service and user-started nix builds processes. ## Why using nix-eval-jobs? -- Faster evaluation due the use of threads -- Memory used for evaluation is reclaimed after nix-eval-jobs is finished so that the build can use it. +- Faster evaluation by using threads +- Memory used for evaluation is reclaimed after nix-eval-jobs finish, so that the build can use it. - Evaluation of jobs can fail individually ## Example @@ -35,7 +36,7 @@ $ nix-eval-jobs --gc-roots-dir $(pwd)/gcroot --flake 'github:NixOS/patchelf#hydr ``` -The output here newline-seperated json according to https://jsonlines.org/ +The output here is newline-seperated json according to https://jsonlines.org. The code is derived from [hydra's](https://github.com/nixos/hydra) eval-jobs executable. @@ -67,8 +68,14 @@ USAGE: nix-eval-jobs [options] expr ## Potential use-cases for the tool -**Faster evaluator in deployment tools.** When evaluating nixos machines evaluation can take several minutes when performed on a single core. -This limits the scalability for large deployment with deployment tools such as [NixOps](https://github.com/NixOS/nixops). -**Faster evaluator in CI.** In addition to evaluation speed for CIs it is also useful if evaluation of individual jobs can fail in CIs in contrast to failing the whole jobset. -Furthermore for CIs that allow to create dynamic build steps, one can leverage the fact that nix-eval-jobs outputs derivation path seperatly. -This allows to have seperate logs and success status per job rather than one big log file. +**Faster evaluator in deployment tools.** When evaluating NixOS machines, +evaluation can take several minutes when run on a single core. This limits +scalability for large deployments with deployment tools such as +[NixOps](https://github.com/NixOS/nixops). + +**Faster evaluator in CIs.** In addition to evaluation speed for CIs, it is also +useful if evaluation of individual jobs in CIs can fail, as opposed to failing +the entire jobset. For CIs that allow dynamic build steps to be created, one +can also take advantage of the fact that nix-eval-jobs outputs the derivation +path separately. This allows separate logs and success status per job instead +of a single large log file.