1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116

//! Entry point.

use crate::db::Db;
use crate::message::{Message, Type};
use crate::settings::Settings;
use crate::value::Value;
use clap::Arg;
use crossbeam_channel::{Receiver, Sender};
use failure::{format_err, Error};
use log::{debug, info, warn, Level};
use std::sync::{Arc, Mutex};

pub mod consts;
pub mod db;
pub mod message;
pub mod persistence;
pub mod services;
pub mod settings;
pub mod supervisor;
pub mod templates;
pub mod value;
pub mod web;

type Result<T> = std::result::Result<T, Error>;

const DEFAULT_SETTINGS_PATH: &str = "my-iot.toml";
const DEFAULT_DB_PATH: &str = "my-iot.sqlite3";

/// Entry point.
fn main() -> Result<()> {
    simple_logger::init_with_level(Level::Info)?;

    let matches = clap::App::new("My IoT")
        .version(clap::crate_version!())
        .about(clap::crate_description!())
        .arg(
            Arg::with_name("settings")
                .short("s")
                .long("settings")
                .takes_value(true)
                .help(&format!("Settings file path (default: {})", DEFAULT_SETTINGS_PATH)),
        )
        .arg(
            Arg::with_name("db")
                .long("--db")
                .takes_value(true)
                .help(&format!("Database file path (default: {})", DEFAULT_DB_PATH)),
        )
        .get_matches();

    info!("Reading settings…");
    let settings = settings::read(matches.value_of("settings").unwrap_or(DEFAULT_SETTINGS_PATH))?;
    debug!("Settings: {:?}", &settings);

    info!("Opening database…");
    let db = Arc::new(Mutex::new(Db::new(matches.value_of("db").unwrap_or(DEFAULT_DB_PATH))?));

    // Starting up multi-producer multi-consumer bus:
    // - services create and return their input channels
    // - services send their messages out to `dispatcher_tx`
    // - the dispatcher sends out each message from `dispatcher_rx` to the services input channels
    info!("Starting services…");
    let (dispatcher_tx, dispatcher_rx) = crossbeam_channel::unbounded();
    dispatcher_tx.send(Message::now(Type::OneOff, "my-iot::start", Value::None))?;
    let mut all_txs = vec![persistence::spawn(db.clone(), &dispatcher_tx)?];
    all_txs.extend(spawn_services(&settings, &db, &dispatcher_tx)?);
    spawn_dispatcher(dispatcher_rx, dispatcher_tx, all_txs)?;

    info!("Starting web server on port {}…", settings.http_port);
    web::start_server(settings, db.clone())
}

/// Spawn all configured services.
///
/// Returns a vector of all service input message channels.
///
/// - `tx`: output message channel that's used by services to send their messages to.
fn spawn_services(settings: &Settings, db: &Arc<Mutex<Db>>, tx: &Sender<Message>) -> Result<Vec<Sender<Message>>> {
    let mut service_txs = Vec::new();

    for (service_id, service_settings) in settings.services.iter() {
        if !settings.disabled_services.contains(service_id.as_str()) {
            info!("Spawning service `{}`…", service_id);
            debug!("Settings `{}`: {:?}", service_id, service_settings);
            service_txs.extend(services::spawn(service_id, service_settings, &db, tx)?);
        } else {
            warn!("Service `{}` is disabled.", &service_id);
        }
    }

    Ok(service_txs)
}

/// Spawn message dispatcher that broadcasts every received message to emulate
/// a multi-producer multi-consumer queue.
///
/// Thus, services exchange messages with each other. Each message from the input channel is
/// broadcasted to each of output channels.
///
/// - `rx`: dispatcher input message channel
/// - `tx`: dispatcher output message channel
/// - `txs`: service output message channels
fn spawn_dispatcher(rx: Receiver<Message>, tx: Sender<Message>, txs: Vec<Sender<Message>>) -> Result<()> {
    info!("Spawning message dispatcher…");
    supervisor::spawn("my-iot::dispatcher", tx, move || -> Result<()> {
        for message in &rx {
            debug!("Dispatching {}", &message.reading.sensor);
            for tx in txs.iter() {
                tx.send(message.clone())?;
            }
            debug!("Dispatched {}", &message.reading.sensor);
        }
        Err(format_err!("Receiver channel is unexpectedly exhausted"))
    })?;
    Ok(())
}