file-per-thread-logger 0.1.2

A logging implementation that writes logs in one file per thread
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
139
140
141

use tempfile::tempdir;

use file_per_thread_logger::initialize;

use log::{debug, error, info, trace, warn};
use std::env;
use std::fs;
use std::io;
use std::path::Path;
use std::thread;

fn no_log_file_exists() -> io::Result<bool> {
    let current_dir = env::current_dir()?;
    for entry in fs::read_dir(current_dir.as_path())? {
        let path = entry?.path();
        if let Some(filename) = path.file_name() {
            if filename.to_string_lossy().starts_with("my_log_test-") {
                return Ok(false);
            }
        }
    }
    Ok(true)
}

fn flush() {
    log::logger().flush();
}

fn do_log(run_init: bool) {
    trace!("This is a trace entry on the main thread.");
    debug!("This is a debug entry on the main thread.");
    info!("This is an info entry on the main thread.");
    warn!("This is a warn entry on the main thread.");
    error!("This is an error entry on the main thread.");

    let handle = thread::spawn(move || {
        if run_init {
            initialize("my_log_test-");
        }
        trace!("This is a trace entry from an unnamed helper thread.");
        debug!("This is a debug entry from an unnamed helper thread.");
        info!("This is an info entry from an unnamed helper thread.");
        warn!("This is a warn entry from an unnamed helper thread.");
        error!("This is an error entry from an unnamed helper thread.");
        flush();
    });

    handle.join().unwrap();

    let handle = thread::Builder::new()
        .name("helper".to_string())
        .spawn(move || {
            if run_init {
                initialize("my_log_test-");
            }
            trace!("This is a trace entry from a named thread.");
            debug!("This is a debug entry from a named thread.");
            info!("This is an info entry from a named thread.");
            warn!("This is a warn entry from a named thread.");
            error!("This is an error entry from a named thread.");
            flush();
        })
        .unwrap();

    handle.join().unwrap();
    flush();
}

#[test]
fn tests() -> io::Result<()> {
    let temp_dir = tempdir()?;
    env::set_current_dir(&temp_dir)?;

    assert!(no_log_file_exists()?);

    env::remove_var("RUST_LOG");
    initialize("my_log_test-");

    // Nothing should be logged without something in the RUST_LOG env variable..
    assert!(no_log_file_exists()?);
    do_log(false);
    assert!(no_log_file_exists()?);

    // When the RUST_LOG variable is set, it will create the main thread file even though nothing
    // has been logged yet.
    env::set_var("RUST_LOG", "info");
    initialize("my_log_test-");
    flush();

    let main_log = Path::new("my_log_test-tests");
    let named_log = Path::new("my_log_test-helper");
    // do_log spawns 2 threads. This is the second time we call do_log, and we start counting from
    // 1 (main thread). So the second unnamed thread has id = 4.
    let unnamed_log = Path::new("my_log_test-ThreadId4");

    assert!(main_log.exists());
    assert_eq!(
        fs::read_to_string(main_log)?,
        r#"INFO - Set up logging; filename prefix is my_log_test-
"#
    );

    assert!(!unnamed_log.exists());
    assert!(!named_log.exists());

    do_log(true);

    // It then creates files for each thread with logged contents.
    assert!(main_log.exists());
    assert_eq!(
        fs::read_to_string(main_log)?,
        r#"INFO - Set up logging; filename prefix is my_log_test-
INFO - This is an info entry on the main thread.
WARN - This is a warn entry on the main thread.
ERROR - This is an error entry on the main thread.
"#
    );

    assert!(unnamed_log.exists());
    assert_eq!(
        fs::read_to_string(unnamed_log)?,
        r#"INFO - Set up logging; filename prefix is my_log_test-
INFO - This is an info entry from an unnamed helper thread.
WARN - This is a warn entry from an unnamed helper thread.
ERROR - This is an error entry from an unnamed helper thread.
"#
    );

    assert!(named_log.exists());
    assert_eq!(
        fs::read_to_string(named_log)?,
        r#"INFO - Set up logging; filename prefix is my_log_test-
INFO - This is an info entry from a named thread.
WARN - This is a warn entry from a named thread.
ERROR - This is an error entry from a named thread.
"#
    );

    temp_dir.close()?;
    Ok(())
}