Crate fs_err

fs-err is a drop-in replacement for std::fs that provides more helpful messages on errors. Extra information includes which operations was attempted and any involved paths.

Error Messages

Using std::fs, if this code fails:

let file = File::open("does not exist.txt")?;

The error message that Rust gives you isn’t very useful:

The system cannot find the file specified. (os error 2)

…but if we use fs-err instead, our error contains more actionable information:

failed to open file `does not exist.txt`: The system cannot find the file specified. (os error 2)

Usage

fs-err’s API is the same as std::fs, so migrating code to use it is easy.

// use std::fs;
use fs_err as fs;

let contents = fs::read_to_string("foo.txt")?;

println!("Read foo.txt: {}", contents);

fs-err uses std::io::Error for all errors. This helps fs-err compose well with traits from the standard library like std::io::Read and crates that use them like serde_json:

use fs_err::File;

let file = File::open("my-config.json")?;

// If an I/O error occurs inside serde_json, the error will include a file path
// as well as what operation was being performed.
let decoded: Vec<String> = serde_json::from_reader(file)?;

println!("Program config: {:?}", decoded);

Feature flags

• expose_original_error: when enabled, the Error::source() method of errors returned by this crate return the original io::Error. To avoid duplication in error messages, this also suppresses printing its message in their Display implementation, so make sure that you are printing the full error chain.

Minimum Supported Rust Version

The oldest rust version this crate is tested on is 1.40.

This crate will generally be conservative with rust version updates. It uses the autocfg crate to allow wrapping new APIs without incrementing the MSRV.

If the tokio feature is enabled, this crate will inherit the MSRV of the selected tokio version.

Modules

• os
  OS-specific functionality.
• tokiotokio
  Tokio-specific wrappers that use fs_err error messages.

Structs

• DirEntry
  Wrapper around std::fs::DirEntry which adds more helpful information to all errors.
• File
  Wrapper around std::fs::File which adds more helpful information to all errors.
• OpenOptions
  Wrapper around std::fs::OpenOptions
• ReadDir
  Wrapper around std::fs::ReadDir which adds more helpful information to all errors.

Traits

• PathExt
  Defines aliases on Path for fs_err functions.

Functions

• canonicalize
  Returns the canonical, absolute form of a path with all intermediate components normalized and symbolic links resolved.
• copy
  Copies the contents of one file to another. This function will also copy the permission bits of the original file to the destination file.
• create_dir
  Creates a new, empty directory at the provided path.
• create_dir_all
  Recursively create a directory and all of its parent components if they are missing.
• hard_link
  Creates a new hard link on the filesystem.
• metadata
  Given a path, query the file system to get information about a file, directory, etc.
• read
  Read the entire contents of a file into a bytes vector.
• read_dir
  Returns an iterator over the entries within a directory.
• read_link
  Reads a symbolic link, returning the file that the link points to.
• read_to_string
  Read the entire contents of a file into a string.
• remove_dir
  Removes an empty directory.
• remove_dir_all
  Removes a directory at this path, after removing all its contents. Use carefully!
• remove_file
  Removes a file from the filesystem.
• rename
  Rename a file or directory to a new name, replacing the original file if to already exists.
• set_permissions
  Changes the permissions found on a file or a directory.
• soft_linkDeprecated
  Wrapper for fs::soft_link.
• symlink_metadata
  Query the metadata about a file without following symlinks.
• write
  Write a slice as the entire contents of a file.