Function decode_json 

pub fn decode_json<T>(payload: &[u8]) -> Result<T, JsonError>
where
    T: DeserializeOwned,

Deserializes a JSON payload, for a decode implementation to call.

Payloads are opaque bytes and need not be JSON, so decoding is left to each product. This helper serves the products whose payloads are. It takes no configuration ID: the client attributes a decode error to the configuration being decoded.

Errors

Returns JsonError if payload is not valid JSON or does not match the shape of T.

Examples

use datadog_agent_remote_config::{decode_json, ConfigId, JsonError, ProductDecoder};
use serde::Deserialize;

#[derive(Deserialize)]
struct Limits {
    max_spans: u32,
}

#[derive(Default)]
struct LimitsDecoder {
    limits: Option<Limits>,
}

impl ProductDecoder for LimitsDecoder {
    const PRODUCT: &'static str = "EXAMPLE_LIMITS";

    type Snapshot = Option<Limits>;
    type Error = JsonError;

    fn decode(&mut self, _id: &ConfigId, payload: &[u8]) -> Result<(), Self::Error> {
        self.limits = Some(decode_json(payload)?);
        Ok(())
    }

    fn build(self) -> Result<Self::Snapshot, Self::Error> {
        Ok(self.limits)
    }
}

let mut decoder = LimitsDecoder::default();
decoder.decode(&ConfigId::new("limits.v1"), br#"{"max_spans": 100}"#).unwrap();
assert!(decoder.decode(&ConfigId::new("limits.v2"), b"{").is_err());
assert_eq!(decoder.build().unwrap().unwrap().max_spans, 100);