crond 0.1.1

A simple Rust crond implementation.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138

use app_dirs::data_root;
use clap::{App, Arg};
use process::Command;
use rustyline::Editor;

use std::{
    env,
    fs::{self, File},
};
use std::{io, process};

fn main() -> io::Result<()> {
    pretty_env_logger::init_custom_env("CRON_LOG");

    let matches = App::new("crontab")
        .author(env!("CARGO_PKG_AUTHORS"))
        .about("A tool to manage cron tables.")
        .version(env!("CARGO_PKG_VERSION"))
        .arg(
            Arg::with_name("find")
                .short("f")
                .required_unless_one(&["edit", "list", "remove"])
                .conflicts_with_all(&["edit", "list", "remove"])
                .help("find user's crontab"),
        )
        .arg(
            Arg::with_name("edit")
                .short("e")
                .required_unless_one(&["find", "list", "remove"])
                .conflicts_with_all(&["find", "list", "remove"])
                .help("edit user's crontab"),
        )
        .arg(
            Arg::with_name("list")
                .short("l")
                .required_unless_one(&["find", "edit", "remove"])
                .conflicts_with_all(&["find", "edit", "remove"])
                .help("list user's crontab"),
        )
        .arg(
            Arg::with_name("remove")
                .short("r")
                .required_unless_one(&["find", "edit", "list"])
                .conflicts_with_all(&["find", "edit", "list"])
                .help("delete user's crontab"),
        )
        .arg(
            Arg::with_name("interactive")
                .short("i")
                .help("prompt before deleting"),
        )
        .arg(
            Arg::with_name("crontab")
                .short("c")
                .help("override the location of the crontab")
                .takes_value(true)
                .value_name("crontab"),
        )
        .get_matches();

    let crontab_path = crond::crontab_path();
    let crontab_path = matches
        .value_of("crontab")
        .unwrap_or(crontab_path.to_str().unwrap());

    if matches.is_present("find") {
        println!("{}", crontab_path);
    } else if matches.is_present("list") {
        if fs::metadata(crontab_path).is_err() {
            eprintln!("no crontab for this user");
            process::exit(1);
        }
        if let Ok(tasks) = crond::read_crontab(crontab_path) {
            for t in tasks {
                println!("{}", t);
            }
        }
    } else if matches.is_present("edit") {
        let mut temp_crontab_path = data_root(app_dirs::AppDataType::UserCache).unwrap();
        temp_crontab_path.push(".crontab.edit");
        if fs::metadata(crontab_path).is_err() {
            eprintln!("no crontab for user - using an empty one");
            File::create(&temp_crontab_path).unwrap();
        } else {
            // Make temp copy of file.
            fs::copy(crontab_path, &temp_crontab_path).unwrap();
        }
        // Open editor
        #[cfg(windows)]
        let editor = env::var("EDITOR").unwrap_or(r"C:\Windows\notepad.exe".to_string());
        #[cfg(not(windows))]
        let editor = env::var("EDITOR").unwrap_or(r"/usr/bin/vi".to_string());
        loop {
            Command::new(&editor)
                .arg(temp_crontab_path.to_str().unwrap())
                .status()
                .unwrap();

            // Verify file and install.
            // TODO: Detect for changes.
            eprintln!("crontab: installing new crontab");
            if crond::read_crontab(&temp_crontab_path).is_ok() {
                fs::copy(temp_crontab_path, crontab_path).unwrap();
                break;
            } else {
                eprintln!("errors in crontab file, can't install!");
                let mut rl = Editor::<()>::new();
                match rl.readline("Do you want to retry the same edit? (Y/N) ") {
                    Ok(line) => {
                        if line.to_lowercase() == "n" {
                            break;
                        }
                    }
                    _ => break,
                }
            }
        }
    } else if matches.is_present("remove") {
        if fs::metadata(crontab_path).is_err() {
            eprintln!("no crontab for this user");
            process::exit(1);
        }
        if matches.is_present("interactive") {
            let mut rl = Editor::<()>::new();
            match rl.readline("crontab: really delete users crontab? ") {
                Ok(line) => {
                    if line.to_lowercase() != "y" {
                        process::exit(0);
                    }
                }
                _ => process::exit(0),
            }
        }
        fs::remove_file(crontab_path).unwrap();
    }

    Ok(())
}