build.rs

use std::{env, path::PathBuf};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut config = prost_build::Config::new();
    config.file_descriptor_set_path(
        PathBuf::from(env::var("OUT_DIR").expect("OUT_DIR environment variable not set"))
            .join("file_descriptor_set.bin"),
    );
    config.compile_protos(&["src/example.proto"], &["src/"])?;

    Ok(())
}

example.proto

syntax = "proto3";

message point {
    uint64 timestamp = 1;
    sint32 sequence = 2;
    uint64 data = 3;
}

main.rs

use prost_reflect::{prost::Message, DescriptorPool, DynamicMessage};
use serde_json::Deserializer;

fn serde() {
  let file_descriptor_set =
  include_bytes!(concat!(env!("OUT_DIR"), "/file_descriptor_set.bin"));
  let context = DescriptorPool::decode(file_descriptor_set.as_ref()).unwrap();

  let mut payload = vec![];

  let message_descriptor = context.get_message_by_name("point").expect("UnconfiguredStream: can");

  let json = r#"{"timestamp": 123,"sequence": 123,"data": 123}"#;
  let mut deserializer = Deserializer::from_str(json);
  let dynamic_message =
    DynamicMessage::deserialize(message_descriptor.clone(), &mut deserializer).unwrap();
  deserializer.end().unwrap();

  dynamic_message.encode(&mut payload).unwrap();

  let dynamic_message =
    DynamicMessage::decode(message_descriptor, payload.as_slice()).unwrap();
  assert_eq!(serde_json::to_string(&dynamic_message).unwrap(), json);
}

stdout.md

'assertion failed: (left == right) left: "{\"timestamp\":\"123\",\"sequence\":123,\"data\":\"123\"}", right: "{\"timestamp\": 123,\"sequence\": 123,\"data\": 123}"'