churn/crates/churn-server/src/main.rs

mod agent;
mod lease;

use std::net::SocketAddr;

use agent::AgentService;
use anyhow::Error;
use axum::extract::{Query, State};
use axum::http::StatusCode;
use axum::response::{IntoResponse, Response};
use axum::routing::{get, post};
use axum::{Json, Router};
use churn_domain::{LeaseResp, ServerEnrollReq, ServerMonitorResp};
use clap::{Parser, Subcommand};
use lease::LeaseService;
use serde::{Deserialize, Serialize};
use serde_json::json;

#[derive(Parser)]
#[command(author, version, about, long_about = None, subcommand_required = true)]
struct Command {
    #[command(subcommand)]
    command: Option<Commands>,
}

#[derive(Subcommand)]
enum Commands {
    Serve {
        #[arg(env = "SERVICE_HOST", long, default_value = "127.0.0.1:3000")]
        host: SocketAddr,
    },
}

#[derive(Clone, Debug, Deserialize, Serialize)]
struct Agent {
    pub name: String,
}

#[derive(Clone)]
struct AppState {
    agent: AgentService,
    leases: LeaseService,
}

#[tokio::main]
async fn main() -> anyhow::Result<()> {
    dotenv::dotenv().ok();
    tracing_subscriber::fmt::init();

    let cli = Command::parse();

    match cli.command {
        Some(Commands::Serve { host }) => {
            tracing::info!("Starting churn server");

            let app = Router::new()
                .route("/ping", get(ping))
                .route("/logs", get(logs))
                .nest(
                    "/agent",
                    Router::new()
                        .route("/enroll", post(enroll))
                        .route("/ping", post(agent_ping))
                        .route("/events", post(get_tasks))
                        .route("/lease", post(agent_lease)),
                )
                .with_state(AppState {
                    agent: AgentService::default(),
                    leases: LeaseService::default(),
                });

            tracing::info!("churn server listening on {}", host);
            axum::Server::bind(&host)
                .serve(app.into_make_service())
                .await
                .unwrap();
        }
        None => {}
    }

    Ok(())
}

enum AppError {
    Internal(Error),
}

impl IntoResponse for AppError {
    fn into_response(self) -> Response {
        let (status, error_message) = match self {
            AppError::Internal(e) => {
                tracing::error!("failed with error: {}", e);

                (
                    StatusCode::INTERNAL_SERVER_ERROR,
                    "failed with internal error",
                )
            }
        };

        let body = Json(json!({
            "error": error_message,
        }));

        (status, body).into_response()
    }
}

async fn enroll(
    State(state): State<AppState>,
    Json(req): Json<ServerEnrollReq>,
) -> Result<Json<Agent>, AppError> {
    let name = state.agent.enroll(req).await.map_err(AppError::Internal)?;

    Ok(Json(Agent { name }))
}

async fn agent_lease(State(state): State<AppState>) -> Result<Json<LeaseResp>, AppError> {
    let lease = state
        .leases
        .create_lease()
        .await
        .map_err(AppError::Internal)?;

    Ok(Json(LeaseResp { token: lease }))
}

async fn agent_ping() -> impl IntoResponse {
    todo!()
}

async fn get_tasks() -> impl IntoResponse {
    todo!()
}

async fn ping() -> impl IntoResponse {
    "pong!"
}

#[derive(Clone, Deserialize)]
struct LogsQuery {
    cursor: Option<String>,
}

async fn logs(Query(cursor): Query<LogsQuery>) -> Result<Json<ServerMonitorResp>, AppError> {
    match cursor.cursor {
        Some(cursor) => {
            tracing::trace!("finding logs from cursor: {}", cursor);
        }
        None => {
            tracing::trace!("finding logs from beginning");
        }
    }

    Ok(Json(ServerMonitorResp {
        cursor: uuid::Uuid::new_v4().to_string(),
        logs: vec!["something".to_string()],
    }))
}