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.
Precious is a code quality tool that lets you run all of your linters and tidiers with a single command. It's features include:
precious.toml, defines all of your linter and tidier commands, as well as what files
they operate on.There are several ways to install this tool.
Install my universal binary installer (ubi) tool and you can
use it to download precious and many other tools.
$> ubi --project houseabsolute/precious --in ~/bin
You can grab a binary release from the releases page. Untar the tarball and put the executable it contains somewhere in your path and you're good to go.
You can also install this via cargo by running cargo install precious. See
the cargo documentation to understand
where the binary will be installed.
Check out this repo's examples directory, which has precious.toml config files for
several languages. Contributions for other languages are welcome!
Also check out the example install-dev-tools.sh script. You
can customize this as needed to install only the tools you need for your project.
Precious is configured via a single precious.toml or .precious.toml file that lives in your
project root. The file is in TOML format.
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. 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.
There are three configuration keys for command invocation. All of them are optional. If none are
specified, precious defaults to this:
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.
invokeThe 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. |
working_dirThe 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_argsThe 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. |
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.
See the Invocation Examples documentation for comprehensive examples of every possible set of options.
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 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 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. |
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 $PRECIOUS_ROOT in any element of the cmd
configuration key. So for example you might write something like this:
cmd = ["some-tidier", "--config", "$PRECIOUS_ROOT/some-tidier.conf"]
The $PRECIOUS_ROOT string will be replaced by the absolute path to the project root.
To get help run precious --help.
The root command takes the following options:
| Flag | Description |
| --------------------------- | ------------------------------------------------------------------- |
| -c, --config <config> | Path to the precious config file |
| -j, --jobs <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 |
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.
The precious command has two subcommands, lint and tidy. You must always specify one of these.
These subcommands take the same options.
When you run precious you must tell it what paths to operate on. There are several options 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. |
| 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 option. |
| 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 options. If any of these paths are directories then that entire directory tree will be included. |
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.
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:
$> precious lint --label some-label --all
The way labels work is as follows:
labels key in its config has one label, default.tidy or lint without a --label flag uses the default label.labels to a command and you want that command included in the default label, you
must explicitly include it:
[command.some-command]
# ...
labels = [ "default", "some-label" ]
When selecting paths precious always respects your ignore files. Right now it only knows how
this works for git, and it will respect all of the following ignore files:
.ignore and .gitignore files..git/info/exclude file.$XDG_CONFIG_HOME/git/ignore.This is implemented using the rust ignore crate, 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.
When precious runs it does the following to determine which commands apply to which paths.
--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.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.
invoke is per-file, then the rules are applied one file at a time.invoke is per-dir, then if any file in the directory matches the rules, the command will
be run on that directory.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.Here are some recommendations for how to get the best experience with precious.
invoke the CommandSome commands might work equally well with invoke set to either per-dir or root. 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.
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 comment 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.
When running in --tidy mode, precious always exits with 0, 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 precious will exit with a non-0 exit code.
There are some configuration scenarios that you may need to handle. Here are some examples:
Some commands, such as 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:
include = "**/*.rs"
invoke = "once"
path_args = "dot" # or "none"
This will cause precious to run the command exactly once in the project root.
If you want to run the command without passing the path being operated on to the command, set
invoke = "per-dir" and path_args = "none":
include = "**/*.rs"
invoke = "per-dir"
path_args = "none"
Use an ignore pattern starting with ! in the exclude list:
[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]
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.
As of version 0.1.2, commands are run in the same order as they appear in the config file.