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

use std::process::Command;
use std::collections::HashMap;
use regex::Regex;

// extract numerical major and minor version from version string
fn parse_version(s: &str) -> (String, String) {
    let re_release = Regex::new(r"^PostgreSQL (\d+)\.(\d+).*$").unwrap();
    let re_devel = Regex::new(r"^PostgreSQL (\d+)devel.*$").unwrap();
    if let Some(caps) = re_release.captures(s) {
        return (caps[1].to_string(), caps[2].to_string())
    }
    if let Some(caps) = re_devel.captures(s) {
        return (caps[1].to_string(), String::from("devel"))
    }
    panic!("unable to parse version string");
}

// extract key and value from the form "KEY = VALUE"
fn parse_line(s: &str) -> (&str, &str) {
    let v: Vec<&str> = s.splitn(2, " = ").collect();

    (v[0], v[1])
}

// parse "K = V" lines into HashMap
fn parse_output(s: &str) -> HashMap<String, String> {
    let mut map = HashMap::new();
    for line in s.lines() {
        let (k, v) = parse_line(line);
        map.insert(k.to_string(), v.to_string());
    }
    map
}

// execute pg_config and return stdout as String
fn pg_config() -> String {
    let output = Command::new("pg_config")
        .output()
        .expect("failed to run pg_config");
    assert!(output.status.success());

    String::from_utf8(output.stdout).unwrap()
}

pub fn postgres() -> HashMap<String, String> {
    let stdout = pg_config();
    let mut map = parse_output(&stdout);

    let (major, minor) = parse_version(&map["VERSION"]);
    map.insert("VERSION_MAJOR".to_string(), major);
    map.insert("VERSION_MINOR".to_string(), minor);
    map
}

#[test]
fn test1() {
    dbg!(postgres());
}