2 releases
0.1.1 | Oct 10, 2023 |
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0.1.0 | Oct 10, 2023 |
#44 in #defined
21KB
443 lines
recursive-env
Look up env variables that are built from other env vars
Why
Shell env vars should evaluate recursively
$ TEST1="test1"
$ TEST2="${TEST1} test2"
$ echo $test
test1 test2
But sometimes tooling sets env vars without evaluating them first. Take this simple program:
fn main() {
env::set_var("TEST1", "test1");
env::set_var("TEST2", "${TEST1} test2");
for (key, value) in env::vars() {
println!("{key}: {value}");
}
}
// TODO: rewrite examples here with asserts. Run theses as part of tests
This will set 'TEST2' to the literal string "${TEST1} test2" instead of evaluating to "test1 test2".
$ cargo run
Finished dev [unoptimized + debuginfo] target(s) in 0.02s
Running `target/debug/test`
TEST1: test1
TEST2: ${TEST1} test2
The solution is to get env vars through recursive_env::var()
instead of std::env::var()
use recursive_env::lookup;
fn main() {
env::set_var("TEST1", "test1");
env::set_var("TEST2", "${TEST1} test 2");
for (key, _) in env::vars() {
let fixed = lookup(key)
println!("{key}: {fixed}");
}
}
$ cargo run
Finished dev [unoptimized + debuginfo] target(s) in 0.02s
Running `target/debug/test`
TEST1: test1
TEST2: test1 test2
Caveats
- Sub expressions are not evaluated
use recursive_env::lookup;
fn main() {
let key = "KEY";
let value = String::from("$(subexpression)");
env::set_var(&key, &value);
assert_eq!(lookup::var(key).unwrap(), value);
}
Dependencies
~135KB