# Precious - One Code Quality Tool to Rule Them All
Who doesn't love linters and tidiers (aka pretty printers)? I sure love them. I love them so much
that in many of my projects I might have five or ten!
Wouldn't it be great if you could run all of them with just one command? Wouldn't it be great if
that command just had one config file to define what tools to run on each part of your project?
Wouldn't it be great if Sauron were our ruler?
Now with Precious you can say "yes" to all of those questions.
## TLDR
Precious is a code quality tool that lets you run all of your linters and tidiers with a single
command. It's features include:
- One file, `precious.toml`, defines all of your linter and tidier commands, as well as what files
they operate on.
- Respects VCS ignore files and allows global and per-command excludes.
- Language-agnostic, and it works the same way with single- or multi-language projects.
- Easy integration with commit hooks and CI systems.
- Commands are executed in parallel by default, with one process per CPU.
- Commands can be grouped with labels, for example to just run a subset of commands for commit hooks
and all commands in CI.
## Installation
There are several ways to install this tool.
### Use ubi
Install my [universal binary installer (ubi)](https://github.com/houseabsolute/ubi) tool and you can
use it to download `precious` and many other tools.
```
$> ubi --project houseabsolute/precious --in ~/bin
```
### Binary Releases
You can grab a binary release from the
[releases page](https://github.com/houseabsolute/precious/releases). Untar the tarball and put the
executable it contains somewhere in your path and you're good to go.
### Cargo
You can also install this via `cargo` by running `cargo install precious`. See
[the cargo documentation](https://doc.rust-lang.org/cargo/commands/cargo-install.html) to understand
where the binary will be installed.
## Getting Started
The `precious` binary has a `config init` subcommand that will generate a config file for you. This
subcommand takes the following flags:
| Flag | Description |
| ------------------------------------------------------------------- | ---------------------------------------------------------------------------------- |
| `-a`, `--auto` | Automatically determines what components to create |
| `-c`, ‑‑component <COMPONENT> | The component(s) to generate config for (see below) |
| `-p`, ‑‑path <PATH> | The path to which the config file should be written. Defaults to `./precious.toml` |
You must pass either `--auto` or at least one `--component`. In `--auto` mode, `precious` will look
at all the files in your project and generate config based on the types of files it finds.
Here's an example for a Rust project:
```
$> precious config init --component rust --component gitignore --component yaml
```
### Components
The following components are supported:
- `go` - Generates config for a Go project which uses [`golangci-lint`](https://golangci-lint.run/)
for linting and tidying.
- `perl` - Generates config for a Perl project which uses a variety of tools, including
[`perlcritic`](https://metacpan.org/dist/Perl-Critic) and
[`perltidy`](https://metacpan.org/dist/Perl-Tidy).
- `rust` - Generates config for a Rust project which uses
[`rustfmt`](https://rust-lang.github.io/rustfmt/) for tidying and
[`clippy`](https://doc.rust-lang.org/stable/clippy/) for linting.
- `shell` - Generated config which uses [`shfmt`](https://github.com/mvdan/sh) for tidying and
[`shellcheck`](https://www.shellcheck.net/) for linting.
- `gitignore` - Generates config to lint and tidy (by sorting) `.gitignore` files using
[`omegasort`](https://github.com/houseabsolute/omegasort).
- `markdown` - Generates config to lint and tidy Markdown files using
[`prettier`](https://prettier.io/).
- `toml` - Generates config to lint and tidy TOML files using [`taplo`](https://taplo.tamasfe.dev/).
- `yaml` - Generates config to lint and tidy YAML files using [`prettier`](https://prettier.io/).
### Examples
This repo's [examples directory](examples) has `precious.toml` config files for several languages.
Contributions for other languages are welcome!
The config in the examples matches what `precious config init` generates, and there are comments in
the files with more details about how you might change this configuration.
Also check out [the example `install-dev-tools.sh`](examples/bin/install-dev-tools.sh) script for a
tool to install all of your project's linting and tidying dependencies. You can customize this as
needed to install only the tools you need for your project.
## Configuration
Precious is configured via a single `precious.toml` or `.precious.toml` file that lives in your
project root. The file is in [TOML format](https://github.com/toml-lang/toml).
There is just one key that can be set in the top level table of the config file:
| Key | Type | Required? | Description |
| --------- | ---------------- | --------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| `exclude` | array of strings | no | Each array member is a pattern that will be matched against potential files when `precious` is run. These patterns are matched in the same way as patterns in a [gitignore file](https://git-scm.com/docs/gitignore#_pattern_format).
You can use lines starting with a `!` to negate the meaning of previous rules in the list, so that anything that matches is _not_ excluded even if it matches previous rules. |
All other configuration is on a per-command basis. A command is something that either tidies (aka
pretty prints or beautifies), lints, or does both. These commands are external programs which
precious will execute as needed.
Each command is defined in a block named something like `[commands.command-name]`. Each name after
the `commands.` prefix must be unique. You **can** have run the same executable differently with
different commands as long as each command has a unique name.
Commands are run in the same order as they appear in the config file.
### Command Invocation
There are three configuration keys for command invocation. All of them are optional. If none are
specified, `precious` defaults to this:
```toml
invoke = "per-file"
working-dir = "root"
path-args = "file"
```
This runs the command once per file with the working directory for the command as the project root.
The command will be passed a relative path to the file from the root as a single argument to the
command.
#### `invoke`
The `invoke` key tells `precious` how the command should be invoked.
| Value | Description |
| ------------ | ---------------------------------------------------------------------- |
| `"per-file"` | Run this command once for each matching file. **This is the default.** |
| `"per-dir"` | Run this command once for each matching directory. |
| `"once"` | Run this command once. |
There are some experimental options for the `invoke` key as well. **The exact names or the details
of how they operate may change in a future release.**
| Value | Description |
| ----------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------- |
| .per‑file‑or‑dir = n | If the number of matching files is less than `n`, run this command once for each matching file. Otherwise run it once for each matching directory. |
| .per‑file‑or‑once = n | If the number of matching files is less than `n`, run this command once for each matching file. Otherwise run it once. |
| .per‑dir‑or‑dir = n | If the number of matching directories is less than `n`, run this command once for each matching directory. Otherwise run it once. |
These are written like this:
```toml
[commands.some-command]
invoke.per-file-or-dir = 42
```
These experimental options are useful for optimizing the speed of running a command. In some cases,
a command can be run in multiple ways, and how quickly it completes depends on how many files or
directories need to be linted or tidied.
The `golangci-lint` tool is a good example. Invoking it multiple times for a few directories can be
much faster than running it against the entire repo. However, once there are enough directories to
check, invoking it once for the entire repo will be faster.
Note that the `path-args` setting needs to work with both possible cases for these options. For
`golangci-lint`, that means setting it to `dir` when using `per-dir-or-once`.
#### `working-dir`
The `working-dir` key tells precious what the working directory should be when the command is run.
| Value | Description |
| ------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `"root"` | The working directory is the project root. **This is the default.** |
| `"dir"` | The working directory is the directory containing the matching files. This means `precious` will `chdir` into each matching directory in turn as it executes the command. |
| .chdir‑to = "path" | The working directory will be the given path when executing the command. **This path must be relative to the project root.** |
##### `working-dir.chdir-to = "path"`
The final option for `working-dir` is to set an explicit path as the working directory.
With this option, the working directory will be set to the given subdirectory when the command is
executed. Relative paths passed to the command will be relative to this subdirectory rather than the
project root.
#### `path-args`
The `path-args` key tells precious how paths should be passed when the command is run.
| Value | Description |
| ----------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `"file"` | Passes the path to the matching file relative to the root. **This is the default.**
With `working-directory.chdir-to` the path is relative to the given working directory. |
| `"dir"` | Passes the path to the directory containing the matching files relative to the root.
With `working-directory.chdir-to` the path is relative to the given working directory. |
| `"none"` | No paths are passed to the command at all. |
| `"dot"` | Always pass `.` as the path. This is useful when `working-dir = "dir"` and the command still requires a path to be passed. |
| "absolute‑file" | Passes the path to the matching file as an absolute path from the filesystem's root directory. |
| "absolute‑dir" | Passes the path to the directory containing the matching files as an absolute path from the filesystem's root directory. |
#### Nonsensical Combinations
Most combinations of these configuration keys are allowed, but there are some nonsensical
combinations that will cause `precious` to exit with an error.
```
invoke = "per-file"
path-args = "dir", "none", "dot", or "absolute-dir"
```
You cannot invoke a command once per file without passing the filename.
```
invoke = "per-dir"
path-args = "none" or "dot"
working-dir = "root"
# ... or ...
working-dir.chdir-to = "whatever"
```
You cannot invoke a command once per directory from a root without passing the directory name or a
list of file names. If you want to run a command once per directory with no path arguments or using
`.` as the path then you _must_ set `working-dir = "dir"`.
```
invoke = "once"
working-dir = "dir"
```
You cannot invoke a command once if the working directory is set to each matching directory in turn.
#### Invocation Examples
See the [Invocation Examples documentation](docs/invocation-examples.md) for comprehensive examples
of every possible set of options.
### Other Per-Command Configuration Keys
The other keys allowed for each command are as follows:
| Key | Type | Required? | Applies To | Default | Description |
| ------------------------- | ---------------------------- | --------- | ------------------------ | ------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `type` | string | **yes** | all | | This must be either `lint`, `tidy`, or `both`. This defines what type of command this is. A command which is `both` **must** define `lint-flags` or `tidy-flags` as well. |
| `include` | string or array of strings | **yes** | all | | Each array member is a [gitignore pattern](https://git-scm.com/docs/gitignore#_pattern_format) that tells `precious` what files this command applies to.
You can use lines starting with a `!` to negate the meaning of previous rules in the list, so that anything that matches is _not_ included even if it matches previous rules. |
| `exclude` | string or array of strings | no | all | | Each array member is a [gitignore pattern](https://git-scm.com/docs/gitignore#_pattern_format) that tells `precious` what files this command should not be applied to.
You can use lines starting with a `!` to negate the meaning of previous rules in the list, so that anything that matches is _not_ excluded even if it matches previous rules. |
| `cmd` | string or array of strings | **yes** | all | | This is the executable to be run followed by any arguments that should always be passed. |
| `env` | table - values are strings | no | all | | This key allows you to set one or more environment variables that will be set when the command is run. The values in this table must be strings. |
| `path-flag` | string | no | all | | By default, `precious` will pass the path being operated on to the command it executes as the final, positional, argument(s). If the command takes paths via a flag you need to specify that flag with this key. |
| `lint-flags` | string or array of strings | no | combined linter & tidier | | If a command is both a linter and tidier then it may take extra flags to operate in linting mode. This is how you set that flag. |
| `tidy-flags` | string or array of strings | no | combined linter & tidier | | If a command is both a linter and tidier then it may take extra flags to operate in tidying mode. This is how you set that flag. |
| `ok-exit-codes` | integer or array of integers | **yes** | all | | Any exit code that **does not** indicate an abnormal exit should be here. For most commands this is just `0` but some commands may use other exit codes even for a normal exit. |
| `lint-failure-exit-codes` | integer or array of integers | no | linters | | If the command is a linter then these are the status codes that indicate a lint failure. These need to be specified so `precious` can distinguish an exit because of a lint failure versus an exit because of some unexpected issue. |
| `ignore-stderr` | string or array of strings | all | all | | By default, `precious` assumes that when a command sends output to `stderr` that indicates a failure to lint or tidy. This parameter can specify one or more regexes. These regexes will be matched against the command's stderr output. If _any_ of the regexes match, the stderr output is ignored. |
| `labels` | string or array of strings | all | all | | One or more labels used to categorize commands. See below for more details. |
### Referencing the Project Root
For commands that can be run from a subdirectory, you may need to specify config files in terms of
the project root. You can do this by using the string `$PRECIOUS_ROOT` in any element of the `cmd`
configuration key. So for example you might write something like this:
```toml
cmd = ["some-tidier", "--config", "$PRECIOUS_ROOT/some-tidier.conf"]
```
The `$PRECIOUS_ROOT` string will be replaced by the absolute path to the project root.
## Running Precious
To get help run `precious --help`.
The root command takes the following flags:
| Flag | Description |
| --------------------------- | ------------------------------------------------------------------- |
| `-c`, `--config` `` | Path to the precious config file |
| `-j`, `--jobs` `` | Number of parallel jobs (threads) to run (defaults to one per core) |
| `-q`, `--quiet` | Suppresses most output |
| `-a`, `--ascii` | Replace super-fun Unicode symbols with terribly boring ASCII |
| `-v`, `--verbose` | Enable verbose output |
| `-V`, `--version` | Prints version information |
| `-d`, `--debug` | Enable debugging output |
| `-t`, `--trace` | Enable tracing output (maximum logging) |
| `-h`, `--help` | Prints help information |
### Parallel Execution
Precious will always execute commands in parallel, with one process per CPU by default. The
execution is parallelized based on the command's invocation configuration. For example, on a 12 CPU
system, a command that has `invoke = "per-file"` will be executed up to 12 times in parallel, with
each command execution receiving one file.
You can disable parallel execution by passing `--jobs 1`.
### Subcommands
The `precious` command has three subcommands, `lint`, `tidy`, and `config`. You must always specify
one of these. The `lint` and `tidy` commands take the same flags:
#### Selecting Paths to Operate On
When you run `precious` you must tell it what paths to operate on. There are several flags for this:
| Mode | Flag | Description |
| ------------------------------------------------------------ | -------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| All paths | `-a`, `--all` | Run on all files under the project root (the directory containing the precious config file). |
| Modified files according to git | `-g`, `--git` | Run on all files that git reports as having been modified, including staged files. |
| Staged files according to git | `-s`, `--staged` | Run on all files that git reports as having been staged. |
| Files that differ from a given git ref | `-d [`, ]‑‑git‑diff‑from | Run on all files in the current `HEAD` that differ from the given `[`. The value `][` can be a branch name, like `master`, or an ref name like `HEAD~6` or `master@{2.days.ago}`. See `git help rev-parse` for more options. Note that this will _not_ see files with uncommitted changes in the local working directory. |
| Staged files according to git, with unstaged changes stashed | ]‑‑staged‑with‑stash | This is like `--stashed`, but it will stash unstaged changes while it runs and pop the stash at the end. This ensures that commands only run against the staged version of your codebase. This can cause issues with many editors or other tools that watch for file changes, so exercise care with this flag. Be careful when using this option in scripts because of this issue. |
| Paths given on CLI | | If you don't pass any of the above flags then `precious` will expect one or more paths to be passed on the command line after all other flags. If any of these paths are directories then that entire directory tree will be included. |
#### Running One Command
You can tidy or lint with just a single command by passing the `--command` flag:
```
$> precious lint --command some-command --all
```
The name passed to `--command` must match the name of the command in your config file. So in the
above example, this would look for a command defined as `[commands.some-command]` in your config.
#### Selecting Commands With Labels
Each command can be assigned one or more labels. This lets you create arbitrary groups of commands.
Then when you tidy or lint you can pick a label by passing a `--label` flag:
```
$> precious lint --label some-label --all
```
The way labels work is as follows:
- A command _without_ a `labels` key in its config has one label, `default`.
- Running `tidy` or `lint` _without_ a `--label` flag uses the `default` label.
- If you assign `labels` to a command and you want that command included in the `default` label, you
must explicitly include it:
```toml
[command.some-command]
# ...
labels = [ "default", "some-label" ]
```
#### Default Exclusions
When selecting paths `precious` _always_ respects your ignore files. Right now it only knows how
this works for git, and it will respect all of the following ignore files:
- Per-directory `.ignore` and `.gitignore` files.
- The `.git/info/exclude` file.
- Global gitignore globs, usually found in `$XDG_CONFIG_HOME/git/ignore`.
This is implemented using the [rust `ignore` crate](https://crates.io/crates/ignore), so adding
support for other VCS systems should be proposed there.
In addition, you can specify excludes for all commands by setting a global `exclude` key.
Finally, you can specify per-command `include` and `exclude` keys.
#### How Include and Exclude Are Applied
When `precious` runs it does the following to determine which commands apply to which paths.
- The base files to operate on are selected based on the command line flag specified. This is one
of:
- `--all` - All files under the project root (the directory containing the precious config file).
- `--git` - All files in the git repo that have been modified, including staged files.
- `--staged` - All files in the git repo that have been staged.
- `--git-diff-from [` - All files in the current `HEAD` that differ from `][`.
- paths passed on the CLI - If a path is a file it is added to the list as-is. If the path is a
directory then all the files under that directory (recursively) are found.
- VCS ignore rules are applied to remove files from this list.
- The global exclude rules are applied to remove files from this list.
- Based on the command's `invoke` key, a list of files to be checked is generated and the command's
include/exclude rules are applied. To be included, a file must match at least one include rule
_and_ not match any exclude rules to be accepted.
- If `invoke` is `per-file`, then the rules are applied one file at a time.
- If `invoke` is `per-dir`, then if any file in the directory matches the rules, the command will
be run on that directory.
- If `invoke` is `once`, then the rules are applied to all of the files at once. If any one of
those files matches the include rule, the command will be run.
### The `config` Subcommand
In addition to the `init` subcommand, this command has a `list` subcommand. This prints a Unicode
table describing the commands in your config file.
```
Found config file at: /home/autarch/projects/precious/precious.toml
┌─────────────────────┬──────┬────────────────────────────────────────────────────────┐
│ Name ┆ Type ┆ Runs │
╞═════════════════════╪══════╪════════════════════════════════════════════════════════╡
│ rustfmt ┆ both ┆ rustfmt --edition 2021 │
├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┤
│ clippy ┆ lint ┆ cargo clippy --locked --all-targets --all-features │
│ ┆ ┆ --workspace -- -D clippy::all │
├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┤
│ prettier ┆ both ┆ ./node_modules/.bin/prettier --no-config --print-width │
│ ┆ ┆ 100 --prose-wrap always │
├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┤
│ omegasort-gitignore ┆ both ┆ omegasort --sort path --unique │
└─────────────────────┴──────┴────────────────────────────────────────────────────────┘
```
## Configuration Recommendations
Here are some recommendations for how to get the best experience with precious.
### Choosing How to `invoke` the Command
Some commands might work equally well with `invoke` set to either `per-dir` or `once`. The right run
mode to choose depends on how you are using precious.
In general, if you either have a very small set of directories, _or_ you are running precious on
most or all of the directories at once, then `once` will be faster.
However, if you have a larger set of directories and you usually only need to lint or tidy a small
subset of these at once, then `per-dir` mode will be faster.
You can also use the experimental `invoke.per-dir-or-once = n` option to invoke the command one of
two ways, depending on the number of directories that precious will operate on.
### Quiet Flags for Commands
Many commands will accept a "quiet" flag of some sort. In general, you probably _do not_ want to run
commands in a quiet mode with precious.
In the case of a successful tidy or lint command execution, precious already hides all stdout from
the command that it runs. If the command fails somehow, precious will print out the command's stdout
and stderr output.
By default, precious treats _any_ output to stderr as an error in the command (as opposed to a
linting failure). You can use the `ignore-stderr` to specify one or more regexes for allowed stderr
output.
In addition, you can see all stdout and stderr output from a command by running precious in
`--debug` mode.
All of which is to say that in general there's no value to running a command in quiet mode with
precious. All that does is make it harder to debug issues with that command when lint checks fail or
other issues occur.
## Exit Codes
When running in `--tidy` mode, precious always exits with `0` if there are no errors when tidying,
whether or not any files are tidied.
When running in `--lint` mode, precious will exit with `0` when all files pass linting. If any lint
commands fail it will exit with `1`.
In both modes, if any commands fail, either by returning exit codes that aren't listed as ok or by
printing to stderr unexpectedly, then the exit code will not be `0` or `1`.
## Common Scenarios
There are some configuration scenarios that you may need to handle. Here are some examples:
### Command runs just once for the entire source tree
Some commands, such as [rust-clippy](https://github.com/rust-lang/rust-clippy), expect to run just
once across the entire source tree, rather than once per file or directory.
In order to make that happen you should use the following config:
```toml
include = "**/*.rs"
invoke = "once"
path-args = "dot" # or "none"
```
This will cause `precious` to run the command exactly once in the project root.
### Command runs in the same directory as the files it lints and does not accept path arguments
If you want to run the command without passing the path being operated on to the command, set
`invoke = "per-dir"`, `working-dir = "dir"`, and `path-args = "none"`:
```toml
include = "**/*.rs"
invoke = "per-dir"
working-dir = "dir"
path-args = "none"
```
### You want a command to exclude an entire directory (tree) except for one or more files
Use an ignore pattern starting with `!` in the `exclude` list:
```toml
[commands.rustfmt]
type = "both"
include = "**/*.rs"
exclude = [
"path/to/dir",
"!path/to/dir/included.rs",
]
cmd = ["rustfmt"]
lint-flags = "--check"
ok-exit-codes = [0]
lint-failure-exit-codes = [1]
```
### You want to run Precious as a commit hook
Simply run `precious lint -s` in your hook. It will exit with a non-zero status if any of the lint
commands indicate a linting problem.
### You want to run commands in a specific order
As of version 0.1.2, commands are run in the same order as they appear in the config file.
## Build Status
### Build and Test
### Cargo Audit Nightly
### Cargo Audit On Push
]