I'm trying to use Rust's config crate to handle a config struct that includes a field with type Vec<String>. I can define my struct and everything compiles, but I can't seem to set the value using an environment variable - it seems like the default environment variable deserialization treats my input as a single string rather than a Vec, so I get the error invalid type: string "[\"a\",\"b\"]", expected a sequence.
Here's a minimal example
// Cargo.toml
[package]
name = "min_config"
version = "0.1.0"
[dependencies]
config = "0.10.1"
serde = { version = "1.0.117", features = ["derive"] }
// src/main.rs
extern crate config;
extern crate serde;
use config::{Config, ConfigError, Environment};
use serde::Deserialize;
#[derive(Debug, Deserialize)]
pub struct MyConfig {
pub strs: Vec<String>,
}
impl MyConfig {
pub fn from_env() -> Result<Self, ConfigError> {
let mut s = Config::new();
s.merge(Environment::with_prefix("CFG"))?;
s.try_into()
}
}
pub fn main() {
let cfg = MyConfig::from_env().unwrap();
}
Running the code:
$ CFG_STRS='["a","b"]' cargo run
Compiling min_config v0.1.0 (/Users/greg/Code/rust/min_config)
Finished dev [unoptimized + debuginfo] target(s) in 0.71s
Running `target/debug/min_config`
thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: invalid type: string "[\"a\",\"b\"]", expected a sequence', src/main.rs:21:13
How can I pass an environment variable in such a way that serde will recognize that it's a Vec<String>, not just a String?
