use serde::{Deserialize, Serialize}; // 1.0.88
use serde_json; // 1.0.38

#[derive(Debug, PartialEq, Serialize, Deserialize)]
struct Application {
    application: Data,
}

#[derive(Debug, PartialEq, Serialize, Deserialize)]
struct Data {
    build: String,
    container_name: String,
    environment: Environment,
}

use std::collections::BTreeMap;

#[derive(Debug, PartialEq, Serialize, Deserialize)]
#[serde(untagged)]
enum Environment {
    Vec(Vec<String>),
    Hash(BTreeMap<String, String>),
}

fn main() {
    let content_vec = r#"
    {
      "application": {
        "build": "something",
        "container_name": "another_thing",
        "environment": [
          "ONE_ENV=fake",
          "SEC_ENV=somethingexample.yml"
        ]
      }
    }
    "#;

    let content_hash = r#"
    {
      "application": {
        "build": "something",
        "container_name": "another_thing",
        "environment": {
          "ONE_ENV": "fake",
          "SEC_ENV": "somethingexample.yml"
        }
      }
    }
    "#;

    let application_data: Application = serde_json::from_str(content_vec).unwrap();
    println!("{:?}", application_data.application.environment);

        let application_data: Application = serde_json::from_str(content_hash).unwrap();
    println!("{:?}", application_data.application.environment);
}