Improve error handling

+ Alias for returning Result with varying Error types
+ Update all Result returns to use new alias
+ Documentation comments for functions and structs
+ Add move_dir and move_file functions to fs wrapper module
+ Add `--force` flag for overwriting an existing configuration backup
This commit is contained in:
Shaun Reed 2021-12-29 13:31:09 -05:00
parent fded317a65
commit 069f5cc128
5 changed files with 174 additions and 83 deletions

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@ -13,20 +13,24 @@ pub mod cli;
pub mod fs; pub mod fs;
pub mod io; pub mod io;
/// Result alias to return result with Error of various types
pub type Result<T> = std::result::Result<T, Box<dyn std::error::Error>>;
// ============================================================================= // =============================================================================
// IMPLEMENTATION // IMPLEMENTATION
// ============================================================================= // =============================================================================
// ----------------------------------------------------------------------------- // -----------------------------------------------------------------------------
// Creates symbolic links to the configurations we're installing /// Creates symbolic links to the configurations we're installing
// TODO: On error, revert to last good state // TODO: On error, revert to last good state
// TODO: User script to execute after installing configs successfully // TODO: User script to execute after installing configs successfully
// TODO: Function to uninstall configs. Loop through dotfiles and restore backup files or delete configs pub fn install_configs(args: & cli::Cli) -> Result<()> {
pub fn install_configs(args: & cli::Cli) -> std::io::Result<()> {
// Get the configurations and their target installation paths // Get the configurations and their target installation paths
// + Checks for conflicts and prompts user to abort or continue // + Checks for conflicts and prompts user to abort or continue
let config_map = fs::get_target_paths(&args)?; let config_map = fs::get_target_paths(&args)?;
// Check if there are any existing files in the install directory that are also within the dotfiles to install
handle_collisions(&args, &config_map)?; handle_collisions(&args, &config_map)?;
// At this point there are either no conflicts or the user agreed to them // At this point there are either no conflicts or the user agreed to them
@ -36,7 +40,7 @@ pub fn install_configs(args: & cli::Cli) -> std::io::Result<()> {
match std::os::unix::fs::symlink(config_path, target_path) { match std::os::unix::fs::symlink(config_path, target_path) {
Ok(()) => (), // Configuration installed successfully Ok(()) => (), // Configuration installed successfully
Err(_e) => { Err(_e) => {
// Attempt to remove the file or directory, and then symlink the new config // Attempt to remove the file or directory first, and then symlink the new config
match target_path.is_dir() { match target_path.is_dir() {
true => fs_extra::dir::remove(target_path) true => fs_extra::dir::remove(target_path)
.expect(&format!("Error: Unable to remove directory: {:?}", target_path)), .expect(&format!("Error: Unable to remove directory: {:?}", target_path)),
@ -44,21 +48,23 @@ pub fn install_configs(args: & cli::Cli) -> std::io::Result<()> {
.expect(&format!("Error: Unable to remove file: {:?}", target_path)), .expect(&format!("Error: Unable to remove file: {:?}", target_path)),
}; };
// Try to symlink the config again, if failure exit with error // Try to symlink the config again, if failure exit with error
std::os::unix::fs::symlink(config_path, target_path) std::os::unix::fs::symlink(config_path, target_path)?;
.expect(&format!("Unable to symlink config: {:?}", config_path));
}, },
} }
} }
Ok(()) Ok(())
} }
/// Handles collisions between existing files and dotfiles we're installing
fn handle_collisions(args : & cli::Cli, fn handle_collisions(args : & cli::Cli,
config_map : & fs::HashMap<PathBuf, PathBuf>) -> io::Result<()> { config_map : & fs::HashMap<PathBuf, PathBuf>) -> Result<()> {
let conflicts = check_collisions(&config_map) // Check if we found any collisions in the configurations
.expect("Error: Failed to check collisions"); match check_collisions(&config_map) {
None => {
// If we found collisions in the configurations return Ok(()) // There were no collisions, configurations pass pre-install checks
if &conflicts.len() > &0 { },
Some(conflicts) => {
// Ask client if they would like to abort given the config collisions // Ask client if they would like to abort given the config collisions
let mut msg = format!("The following configurations already exist:"); let mut msg = format!("The following configurations already exist:");
for config in conflicts.iter() { for config in conflicts.iter() {
@ -69,44 +75,58 @@ fn handle_collisions(args : & cli::Cli,
\nAbort? Enter y/n or Y/N: ", &args.backup_dir).as_str(); \nAbort? Enter y/n or Y/N: ", &args.backup_dir).as_str();
// If we abort, exit; If we continue, back up the configs // If we abort, exit; If we continue, back up the configs
// TODO: Group this in with the --force flag?; Or make a new --adopt flag?
match io::prompt(msg) { match io::prompt(msg) {
true => return Err(std::io::Error::from(std::io::ErrorKind::AlreadyExists)), true => return Ok(()),
false => { false => {
// Backup each conflicting config at the install location // Backup each conflicting config at the install location
for backup_target in conflicts.iter() { for backup_target in conflicts.iter() {
backup_config(backup_target, &args.backup_dir) backup_config(backup_target, &args)?;
.expect(format!("Error: Unable to backup config: {:?}", backup_target)
.as_str())
} }
}, },
}; };
},
}; };
Ok(()) Ok(())
} }
// Creates a backup of configurations that conflict // Creates a backup of configurations that conflict
// + Backup directory location is specified by CLI --backup-dir // + Backup directory location is specified by CLI --backup-dir
// TODO: Automatically create backup directory
// TODO: .kotignore in dotfiles repo to specify files to not install / backup // TODO: .kotignore in dotfiles repo to specify files to not install / backup
// TODO: .kotrc in dotfiles repo or home dir to set backup-dir and install-dir? // TODO: .kotrc in dotfiles repo or home dir to set backup-dir and install-dir?
fn backup_config(config_path: & fs::PathBuf, backup_dir: & fs::PathBuf) -> io::Result<()> { fn backup_config(config_path: & fs::PathBuf, args: & cli::Cli) -> Result<()> {
let mut backup_path = backup_dir.to_owned(); let mut backup_path = args.backup_dir.to_owned();
backup_path.push(config_path.file_name().unwrap()); backup_path.push(config_path.file_name().unwrap());
// Check if the configuration we're backing up is a directory or a single file
match config_path.is_dir() { match config_path.is_dir() {
true => { true => {
// Copy directory with recursion using fs_extra::dir::move_dir // Copy directory with recursion using move_dir() wrapper function
let mut options = fs::dir::CopyOptions::new(); let mut options = fs::dir::CopyOptions::new();
options.copy_inside = true; options.copy_inside = true;
// TODO: Add a flag to overwrite backups, otherwise warn and abort options.overwrite = args.force;
options.overwrite = true; if let Err(e) = fs::move_dir(config_path, &backup_path, Some(&options))
fs::dir::move_dir(config_path, backup_path, &options) .map_err(|e| e.into()) {
return Err(e)
}
}, },
false => { false => {
// Copy single configuration file // Copy single configuration file
let mut options = fs_extra::file::CopyOptions::new(); let mut options = fs_extra::file::CopyOptions::new();
options.overwrite = true; options.overwrite = args.force;
fs_extra::file::move_file(config_path, backup_path, &options) if let Err(e) = fs::move_file(config_path, &backup_path, Some(&options))
.map_err(|e| e.into()) {
return Err(e)
}
}, },
}.expect(&format!("Error: Unable to backup config: {:?}", config_path)); }
Ok(())
}
// TODO: Function to uninstall configs.
// + Loops through dotfiles and restore backup files or delete configs
fn _uninstall_configs() -> Result<()> {
Ok(()) Ok(())
} }

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@ -6,6 +6,7 @@
## Contact: shaunrd0@gmail.com | URL: www.shaunreed.com | GitHub: shaunrd0 ## ## Contact: shaunrd0@gmail.com | URL: www.shaunreed.com | GitHub: shaunrd0 ##
##############################################################################*/ ##############################################################################*/
use std::path::Path;
use structopt::StructOpt; use structopt::StructOpt;
// ============================================================================= // =============================================================================
@ -14,6 +15,7 @@ use structopt::StructOpt;
// ----------------------------------------------------------------------------- // -----------------------------------------------------------------------------
/// Struct to outline behavior and features of kot CLI
#[derive(Debug, StructOpt)] #[derive(Debug, StructOpt)]
#[structopt( #[structopt(
name="kot", name="kot",
@ -44,6 +46,12 @@ pub struct Cli {
parse(from_os_str) parse(from_os_str)
)] )]
pub backup_dir: std::path::PathBuf, pub backup_dir: std::path::PathBuf,
#[structopt(
help="Overwrites existing backups",
short, long
)]
pub force: bool,
} }
// ============================================================================= // =============================================================================
@ -52,28 +60,54 @@ pub struct Cli {
// ----------------------------------------------------------------------------- // -----------------------------------------------------------------------------
// Augment implementation of from_args to limit scope of StructOpt /// Augment implementation of from_args to limit scope of StructOpt
// + Also enforces use of Cli::normalize() /// + Also enforces use of Cli::normalize()
// https://docs.rs/structopt/0.3.23/src/structopt/lib.rs.html#1121-1126 /// + https://docs.rs/structopt/0.3.23/src/structopt/lib.rs.html#1121-1126
pub fn from_args() -> Cli { pub fn from_args() -> super::Result<Cli> {
let s = Cli::from_clap(&Cli::clap().get_matches()); let s = Cli::from_clap(&Cli::clap().get_matches());
s.normalize() s.normalize()
} }
impl Cli { impl Cli {
// Helper function to normalize arguments passed to program /// Helper function to normalize arguments passed to program
pub fn normalize(mut self) -> Self { pub fn normalize(mut self) -> super::Result<Self> {
// If the path to the dotfiles doesn't exist, exit with error // If the path to the dotfiles doesn't exist, exit with error
if !&self.dotfiles_dir.exists() { if !&self.dotfiles_dir.exists() {
panic!("Error: Dotfiles configuration at {:?} does not exist", self.dotfiles_dir); panic!("Error: Dotfiles configuration at {:?} does not exist", self.dotfiles_dir);
} }
self.dotfiles_dir = self.dotfiles_dir.canonicalize().unwrap(); self.dotfiles_dir = self.dotfiles_dir.canonicalize()?;
// If either the install or backup dir don't exist, create them // If either the install or backup dir don't exist, create them
std::fs::create_dir_all(&self.install_dir).ok(); std::fs::create_dir_all(&self.install_dir)?;
self.install_dir = self.install_dir.canonicalize().unwrap(); self.install_dir = self.install_dir.canonicalize()?;
std::fs::create_dir_all(&self.backup_dir).ok(); std::fs::create_dir_all(&self.backup_dir)?;
self.backup_dir = self.backup_dir.canonicalize().unwrap(); self.backup_dir = self.backup_dir.canonicalize()?;
self
// + To enforce the correction when error is encountered
// Get the number of configs currently in backup directory
// + An empty backup directory returns a count of 1
let current_backups = self.backup_dir.read_dir()?.count();
// If there are files in the backup directory already
if current_backups > 1 {
// If the --force flag is not set, warn and abort
if !self.force {
panic!("\n Error: Backups already exist at {:?}\
\n Set the --force flag to overwrite configurations stored here" , self.backup_dir)
}
// If the --force flag is set, remove backups and create new
// + Move backups to /tmp/<BACKUP_DIRNAME>
// + If we encounter an error, we can move these temp files back to args.backup_dir
// + On success we can delete them since new backups will have been created at args.backup_dir
let mut options = fs_extra::dir::CopyOptions::new();
options.copy_inside = true;
options.overwrite = true;
let mut temp_path = Path::new("/tmp/").to_path_buf();
temp_path.push(self.backup_dir.file_name().unwrap());
// Move the old backups to /tmp/ and create a new empty backup directory
super::fs::move_dir( &self.backup_dir, &temp_path, Some(&options))?;
std::fs::create_dir_all(&self.backup_dir)?;
}
Ok(self)
} }
} }

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@ -19,39 +19,36 @@ use std::fs;
// ----------------------------------------------------------------------------- // -----------------------------------------------------------------------------
// Initialize and return a HashMap<config_dir, config_install_location> /// Initialize and return a HashMap<config_dir, config_install_location>
// Later used to check each install location for conflicts before installing /// + Later used to check each install location for conflicts before installing
// This function does not create or modify any files or directories /// + This function does not create or modify any files or directories
pub fn get_target_paths(args: & super::cli::Cli) -> super::io::Result<HashMap<PathBuf, PathBuf>> { pub fn get_target_paths(args: & super::cli::Cli) -> super::Result<HashMap<PathBuf, PathBuf>> {
let mut config_map = HashMap::new(); let mut config_map = HashMap::new();
// Local variable for the installation directory as an absolute path // Local variable for the installation directory as an absolute path
let mut config_target = args.install_dir.to_owned(); let mut config_target = args.install_dir.to_owned();
// For each file or directory within the dotfiles we're installing // For each file or directory within the dotfiles we're installing
for config_entry in fs::read_dir(&args.dotfiles_dir)? { for config_entry in fs::read_dir(&args.dotfiles_dir)? {
// Match result from reading each item in dotfiles, return error if any let entry = config_entry?;
match config_entry {
Err(err) => return Err(err),
Ok(entry) => {
// Create full path to target config file (or directory) by push onto install path // Create full path to target config file (or directory) by push onto install path
config_target.push(entry.file_name()); config_target.push(entry.file_name());
// If the entry doesn't already exist, insert it into the config_map // If the entry doesn't already exist, insert it into the config_map
// Key is full path to source config from dotfiles repo we're installing // + Key is full path to source config from dotfiles repo we're installing
// Value is desired full path to config at final install location // + Value is desired full path to config at final install location
// TODO: If the entry does exist, should there be an exception? // TODO: If the entry does exist, should there be an exception?
config_map.entry(entry.path().to_owned()) config_map.entry(entry.path().to_owned())
.or_insert(config_target.to_owned()); .or_insert(config_target.to_owned());
// Reset config_target to be equal to requested install_dir // Reset config_target to be equal to requested install_dir
config_target.pop(); config_target.pop();
},
}
} }
Ok(config_map) Ok(config_map)
} }
pub fn check_collisions(config_map : & HashMap<PathBuf, PathBuf>) -> super::io::Result<Vec<PathBuf>> { /// Checks if any config to install collides with existing files or directories
/// + Returns a count of collisions within Some(), else returns None
pub fn check_collisions(config_map : & HashMap<PathBuf, PathBuf>) -> Option<Vec<PathBuf>> {
let mut config_conflicts = vec![]; let mut config_conflicts = vec![];
for (_path, target_config) in config_map.iter() { for (_path, target_config) in config_map.iter() {
// If the target configuration file or directory already exists // If the target configuration file or directory already exists
@ -59,6 +56,35 @@ pub fn check_collisions(config_map : & HashMap<PathBuf, PathBuf>) -> super::io::
config_conflicts.push(target_config.to_owned()); config_conflicts.push(target_config.to_owned());
} }
} }
Ok(config_conflicts) if config_conflicts.len() > 0 {
return Some(config_conflicts)
}
return None
} }
/// Moves a single file from one location to another; Can be used to rename files
/// + To specify options such as overwrite for the copy operation, a custom CopyOptions can be provided
pub fn move_file(src: & PathBuf, dst: & PathBuf,
options: Option< & fs_extra::file::CopyOptions>) -> super::Result<()> {
if options.is_none() {
// Default CopyOptions for moving files
let mut options = fs_extra::file::CopyOptions::new();
options.overwrite = false;
}
fs_extra::file::move_file(src, dst, options.unwrap())?;
Ok(())
}
/// Moves a directory and all of it's contents recursively
/// + To specify options such as overwrite for the copy operation, a custom CopyOptions can be provided
pub fn move_dir(src: & PathBuf, dst: & PathBuf,
options: Option< & fs_extra::dir::CopyOptions>) -> super::Result<()> {
if options.is_none() {
// Default CopyOptions for moving directories
let mut options = fs_extra::dir::CopyOptions::new();
options.copy_inside = true;
options.overwrite = false;
}
fs_extra::dir::move_dir(src, dst, options.unwrap())?;
Ok(())
}

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@ -17,8 +17,8 @@ use std::io;
// ----------------------------------------------------------------------------- // -----------------------------------------------------------------------------
// Asks user for y/n Y/N input, returns true/false respectively /// Asks user for y/n Y/N input, returns true/false respectively
// + Prompt output defined by msg parameter String /// + Prompt output defined by msg parameter String
pub fn prompt(msg: String) -> bool { pub fn prompt(msg: String) -> bool {
println!("{}", msg); println!("{}", msg);
let mut reply = String::new(); let mut reply = String::new();

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@ -6,6 +6,8 @@
## Contact: shaunrd0@gmail.com | URL: www.shaunreed.com | GitHub: shaunrd0 ## ## Contact: shaunrd0@gmail.com | URL: www.shaunreed.com | GitHub: shaunrd0 ##
##############################################################################*/ ##############################################################################*/
use std::path::PathBuf;
mod kot; mod kot;
// ============================================================================= // =============================================================================
@ -14,9 +16,9 @@ mod kot;
// ----------------------------------------------------------------------------- // -----------------------------------------------------------------------------
fn main() { fn main() -> kot::Result<()> {
// Call augmented kot::cli::from_args() to parse CLI arguments // Call augmented kot::cli::from_args() to parse CLI arguments
let args = kot::cli::from_args(); let args = kot::cli::from_args()?;
// At this point all paths exist and have been converted to absolute paths // At this point all paths exist and have been converted to absolute paths
println!("args: {:?}\n", args); println!("args: {:?}\n", args);
@ -26,10 +28,19 @@ fn main() {
// If there was an error, show the error type and run settings // If there was an error, show the error type and run settings
println!( println!(
"Error: {:?}\n+ Configs used: {:?}\n+ Install directory: {:?}\n", "Error: {:?}\n+ Configs used: {:?}\n+ Install directory: {:?}\n",
e.kind(), args.dotfiles_dir, args.install_dir e, args.dotfiles_dir, args.install_dir
) );
},
// Configurations installed successfully // If we were forcing a backup and met some error, revert backups to last good state
Ok(()) => (), // TODO: Isolate this to limit error scope to backup related functions
if args.force {
let mut temp_path : PathBuf = kot::fs::Path::new("/tmp/").to_path_buf();
temp_path.push(args.backup_dir.file_name().unwrap());
kot::fs::move_dir(&temp_path, &args.backup_dir, None)?;
} }
},
_ => ()
}
// Configurations installed successfully
Ok(())
} }