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pub fn env_or_opt<T, K, D>(key: K, default: D) -> Option<T>
where
T: std::str::FromStr,
K: core::fmt::Display,
D: core::fmt::Display,
{
let key = key.to_string();
let default = default.to_string();
let base = std::env::var(key).ok();
if base.is_some() {
let parsed = base.unwrap().parse::<T>().ok();
if parsed.is_some() {
return parsed;
}
}
default.parse::<T>().ok()
}
pub fn env_or<T, K, D>(key: K, default: D) -> T
where
T: std::str::FromStr,
K: core::fmt::Display,
D: core::fmt::Display,
{
env_or_opt(key, default).unwrap()
}
pub fn env_string_or<K, D>(key: K, default: D) -> String
where
K: core::fmt::Display,
D: core::fmt::Display,
{
let key = key.to_string();
let default = default.to_string();
if let Ok(value) = std::env::var(key) {
return value;
}
default
}
pub fn env_true<K>(key: K) -> bool
where
K: core::fmt::Display,
{
let key = key.to_string();
if let Ok(value) = std::env::var(key) {
return value.to_lowercase() == "true";
}
false
}
#[test]
fn test() {
let flag = env_true("FLAG_ONLY_TRUE_WHEN_DEFINED_AND_ITS_LOWER_CASE_IS_EQUAL_TO_TRUE");
assert_eq!(flag, false);
std::env::set_var(
"FLAG_ONLY_TRUE_WHEN_DEFINED_AND_ITS_LOWER_CASE_IS_EQUAL_TO_TRUE",
"tRUe",
);
let flag = env_true("FLAG_ONLY_TRUE_WHEN_DEFINED_AND_ITS_LOWER_CASE_IS_EQUAL_TO_TRUE");
assert_eq!(flag, true);
std::env::set_var(
"FLAG_ONLY_TRUE_WHEN_DEFINED_AND_ITS_LOWER_CASE_IS_EQUAL_TO_TRUE",
"tRUeX",
);
let flag = env_true("FLAG_ONLY_TRUE_WHEN_DEFINED_AND_ITS_LOWER_CASE_IS_EQUAL_TO_TRUE");
assert_eq!(flag, false);
std::env::set_var(
"FLAG_ONLY_TRUE_WHEN_DEFINED_AND_ITS_LOWER_CASE_IS_EQUAL_TO_TRUE",
"TRUE",
);
let flag = env_true("FLAG_ONLY_TRUE_WHEN_DEFINED_AND_ITS_LOWER_CASE_IS_EQUAL_TO_TRUE");
assert_eq!(flag, true);
std::env::remove_var("FLAG_ONLY_TRUE_WHEN_DEFINED_AND_ITS_LOWER_CASE_IS_EQUAL_TO_TRUE");
let flag = env_true("FLAG_ONLY_TRUE_WHEN_DEFINED_AND_ITS_LOWER_CASE_IS_EQUAL_TO_TRUE");
assert_eq!(flag, false);
}