motivation

this rust project implements a rust client to the nix build --log-format internal-json protocol.

it is also an attempt to make nix logging less verbose and more readable by humans by doing this:

• when building several drv(s) in parallel, it accumulate the individual logs and only outputs them when there is an error
• it prevents the print of the nix error summary where you have the error twice in the output but with the hideous indentation

status

• prototype as standalone binary works
  • support for @nix
• minimalist logging
  • support for custom extensions like @cargo
  • add 3 log levels: --level cargo|errors|verbose
    • "cargo" (default): ignores logs from @nix and uses @cargo logs and error detection
    • "errors" only use @nix logs, ignore @cargo messages for the failing build
    • "verbose" shows all @nix messages for each build: successful and failed ones but still in sorted blocks (no mixed logging), ignores all @cargo messages
  • remove --timing / --min-time / --debug
  • print the @cargo internal logs properly & use the exit code
• make it a crate libary
• create demo with https://docs.asciinema.org/manual/server/embedding/
  • successful build
  • build with one error
  • build with two errors
  • build with many targets

a good illustration on how to @nix protocol works and can be implemented. it sometimes shows different results than nix-output-monitor and nix itself:

• NixOS/nix#13909
• NixOS/nix#13910
• NixOS/nix#13935

examples

as an example there are outputs in the tests folder one can experiment with:

the 'normal' monitor:

cat tests/example.stdin2 | cargo run -- --json

the 'verbose' monitor:

cat tests/example.stdin2 | cargo run -- --json -v

license

PUBLIC DOMAIN