Cannot retrieve struct from JSON in Rust - json

Question

I'm having problems obtaining a struct from reading a JSON file.
This is how the config file looks like:
config.json
{
"config_group_1":{
"variable_1": 10
}
}
Its struct is define as:
pub struct ConfigGroup1 {
variable_1: usize
}
pub struct MainConfig {
config_group_1: ConfigGroup1
}
I'm reading the file with a function that returns String in config_content.
let config: Result = serde_json::from_str(&config_content);
But the compiler is pointing to the following error:
missing generics for type alias `serde_json::Result`
expected 1 type argument
help: use angle brackets to add missing type argument: `<T>`rustc(E0107)
How can I solve this? Where to define that MainConfig is the expected type?

Answer 1

It seems that a lot is missing. I suggest you read the following documentation https://docs.serde.rs/serde_json/
Below is a version that might help you
use serde::{Deserialize, Serialize};
use serde_json::Result;
#[derive(Serialize, Deserialize)]
struct MainConfig {
config_group_1: ConfigGroup1
}
#[derive(Serialize, Deserialize)]
pub struct ConfigGroup1 {
variable_1: usize
}
fn main() -> Result<()> {
let data = r#"{"config_group_1": {"variable_1": 10 }}"#;
let p: MainConfig = serde_json::from_str(data).expect("JSON was not well-formatted");
println!("Value {} ", p.config_group_1.variable_1);
Ok(())
}