blacklog 0.1.1

Fast attribute-aware asynchronous logger, port from https://github.com/3Hren/blackhole.
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
142
143
144
145
146
147
148
149
150
151

pub use self::grammar::{expression, ParseError};

// TODO: Implement all functionality.
// [x] format_string := <text> [ format <text> ] *
// [x] format := '{' [ argument ] [ ':' format_spec ] '}'
// [ ] argument := integer | identifier
// [ ] format_spec := [[fill]align][sign]['#'][0][width]['.' precision][type]
// [ ] fill := character
// [ ] align := '<' | '^' | '>'
// [ ] sign := '+' | '-'
// [ ] width := count
// [ ] precision := count | '*'
// [ ] type := identifier | ''
// [-] count := parameter | integer
// [-] parameter := integer '$'

const OPENED_BRACE: &'static str = "{";
const CLOSED_BRACE: &'static str = "}";

peg! grammar(r#"
use super::{Align, Key, SeverityType, Token, OPENED_BRACE, CLOSED_BRACE};

#[pub]
expression -> Vec<Token>
    = (format / text)+
text -> Token
    = "{{" { Token::Literal(OPENED_BRACE.into()) }
    / "}}" { Token::Literal(CLOSED_BRACE.into()) }
    / [^{}]+ { Token::Literal(match_str.into()) }
format -> Token
    = "{" "message" "}" { Token::Message }
    / "{" "message:" align:align? width:width? "}" {
        Token::MessageSpec(Some(' '), align, width)
    }
    / "{" "message:" fill:fill? align:align? width:width? "}" {
        Token::MessageSpec(fill, align, width)
    }
    / "{" "severity" "}" { Token::Severity(None, None, SeverityType::String) }
    / "{" "severity:" align:align? width:width? ty:ty? "}" {
        match ty {
            Some(ty) => Token::Severity(align, width, ty),
            None => Token::Severity(align, width, SeverityType::String),
        }
    }
    / "{" "timestamp" "}" { Token::Timestamp("%+".into()) }
    / "{" key:name "}" { Token::Placeholder(match_str[1..match_str.len() - 1].into(), key) }
fill -> char
    = . { match_str.chars().next().unwrap() }
align -> Align
    = "<" { Align::Left }
    / ">" { Align::Right }
    / "^" { Align::Middle }
width -> usize
    = [0-9]+ { match_str.parse().unwrap() }
ty -> SeverityType
    = "d" { SeverityType::Num }
    / "s" { SeverityType::String }
name -> Key
    = [0-9]+ { Key::Id(match_str.parse().expect("expect number")) }
    / [a-zA-Z][a-zA-Z0-9]* { Key::Name(match_str.into()) }
"#);

// TODO: Format spec.

#[derive(Debug, Clone, PartialEq)]
pub enum Key {
    Id(usize),
    Name(String),
}

#[derive(Debug, Copy, Clone, PartialEq)]
pub enum Align {
    Left,
    Right,
    Middle,
}

#[derive(Debug, Copy, Clone, PartialEq)]
pub enum SeverityType {
    Num,
    String,
}

#[derive(Debug, Clone, PartialEq)]
pub enum Token {
    Literal(String),
    Message,
    MessageSpec(Option<char>, Option<Align>, Option<usize>),
    Severity(Option<Align>, Option<usize>, SeverityType),
    Timestamp(String), // Spec, Pattern, Type[dsl]
    Placeholder(String, Key),
}

pub fn parse(pattern: &str) -> Result<Vec<Token>, ParseError> {
    expression(&pattern)
}

#[cfg(test)]
mod tests {
    use super::{parse, Align, Key, SeverityType, Token};

    #[test]
    fn literal_ast() {
        let tokens = parse("hello").unwrap();

        assert_eq!(vec![Token::Literal("hello".into())], tokens);
    }

    #[test]
    fn message_ast() {
        let tokens = parse("{message}").unwrap();

        assert_eq!(vec![Token::Message], tokens);
    }

    #[test]
    fn message_spec_ast() {
        let tokens = parse("{message:.<10}").unwrap();

        assert_eq!(vec![Token::MessageSpec(Some('.'), Some(Align::Left), Some(10))], tokens);
    }

    #[test]
    fn severity_ast() {
        let tokens = parse("{severity}").unwrap();

        assert_eq!(vec![Token::Severity(None, None, SeverityType::String)], tokens);
    }

    #[test]
    fn severity_with_ty_ast() {
        let tokens = parse("{severity:d}").unwrap();

        assert_eq!(vec![Token::Severity(None, None, SeverityType::Num)], tokens);
    }

    #[test]
    fn timestamp_ast() {
        let tokens = parse("{timestamp}").unwrap();

        assert_eq!(vec![Token::Timestamp("%+".into())], tokens);
    }

    #[test]
    fn placeholder_ast() {
        let tokens = parse("{hello}").unwrap();

        let expected = vec![Token::Placeholder("hello".into(), Key::Name("hello".into()))];
        assert_eq!(expected, tokens);
    }
}