Crate fatal

Utilities for reporting fatal errors and exiting with an error code.

The behavior in this crate is different than the one in panic!-based exits, in that the ones here are suited for display to end-users, i.e. no “thread main panicked at”, no backtrace mentions, etc.

Usage

For unwrapping Results:

• Use expect / expect_fatal to report the error with context.
• Use unwrap_message! to expect with formatting.
• Use unwrap_format! to have more control over the message’s format.
• Use unwrap / unwrap_fatal to report the error when context is provided/obvious.

For aborting:

• Use error! to report context + error.
• Use fatal! when error!’s prefix is unwelcome.

(Pseudo-)Example:

use fatal::UnwrapExt;

const DB_CONSTR_VAR: &str = "DB_CONNECTION_STRING";

fn main() {
    println!("Connecting..");
    let constr: String = fatal::unwrap_message!(std::env::var(DB_CONSTR_VAR), "failed to read the `{}` environment variable", DB_CONSTR_VAR);
    // when doesn't exist, will print: "Error: failed to read the `DB_CONNECTION_STRING` environment variable (environment variable not found)"
    let db: Database = Database::connect(&constr).expect_fatal("failed to connect to database");
    // would also include the actual error as above.

    println!("Querying total users..");
    println!("Total users: {}", db.query_total_users().unwrap_fatal());
}

Macros

• error
  Prints an error message to standard-error and exits with an error code.
• fatal
  Prints to standard-error and exits with an error-code. Returns !.
• unwrap_format
  Unwraps the result or formats an error message and exits.
• unwrap_message
  Unwraps the result or reports the error with the error description and exits.

Traits

• UnwrapExt
  An extension trait for unwrap.

Functions

• expect
  Unwraps a result or reports the given message with the error and exits.
• unwrap
  Unwraps a result or reports its error and exits.