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
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
/*
 * Copyright (C) 2018 Kubos Corporation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

//! A simple API to make standalone Rust applications with high-level hooks
//! for mission life-cycle management
#![deny(missing_docs)]
#![deny(warnings)]

use failure::Error;
use getopts::Options;
use std::env;
use std::fmt;

/// The different ways an application can be started
#[derive(Clone, Debug, PartialEq)]
pub enum RunLevel {
    /// Logic intended to be run if the application is started at system boot time
    OnBoot,
    /// Logic intended to be run if the application is started manually
    OnCommand,
}

impl fmt::Display for RunLevel {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match self {
            RunLevel::OnBoot => write!(f, "OnBoot"),
            RunLevel::OnCommand => write!(f, "OnCommand"),
        }
    }
}

/// Common trait which is used to ensure handlers for all required run levels are defined
pub trait AppHandler {
    /// Called when the application is started at system boot time
    fn on_boot(&self, args: Vec<String>) -> Result<(), Error>;

    /// Called when the application is started on-demand through the `start_app` GraphQL mutation
    fn on_command(&self, args: Vec<String>) -> Result<(), Error>;
}

/// A helper macro which detects the requested run level and calls the appropriate handler function
///
/// # Arguments
///
/// * `handler` - A reference to an object which implements the run level handler functions
///
/// # Examples
///
/// ```
/// extern crate failure;
/// #[macro_use]
/// extern crate kubos_app;
///
/// use failure::Error;
/// use kubos_app::AppHandler;
///
/// struct MyApp;
///
/// impl AppHandler for MyApp {
///   fn on_boot(&self, _args: Vec<String>) -> Result<(), Error> {
///     println!("OnBoot logic");
///     Ok(())
///   }
///   fn on_command(&self, _args: Vec<String>) -> Result<(), Error> {
///     println!("OnCommand logic");
///     Ok(())
///   }
/// }
///
/// fn main() -> Result<(), Error> {
///     let app = MyApp { };
///     app_main!(&app)?;
///     Ok(())
/// }
/// ```
#[macro_export]
macro_rules! app_main {
    ($handler:expr) => {{
        kubos_app::app_start(std::process::id(), $handler)
    }};
}

/// The entry point for all KubOS applications. The preferred way to use this application
/// is through the `app_main!` macro
pub fn app_start(_pid: u32, handler: &AppHandler) -> Result<(), Error> {
    use log4rs::append::console::ConsoleAppender;
    use log4rs::encode::pattern::PatternEncoder;
    use log4rs_syslog::SyslogAppender;
    // Use custom PatternEncoder to avoid duplicate timestamps in logs.
    let syslog_encoder = Box::new(PatternEncoder::new("{m}"));
    // Set up logging which will be routed to syslog for processing
    let syslog = Box::new(
        SyslogAppender::builder()
            .encoder(syslog_encoder)
            .openlog(
                "rust-mission-app",
                log4rs_syslog::LogOption::LOG_PID | log4rs_syslog::LogOption::LOG_CONS,
                log4rs_syslog::Facility::User,
            )
            .build(),
    );

    // Set up logging which will be routed to stdout
    let stdout = Box::new(ConsoleAppender::builder().build());

    // Combine the loggers into one master config
    let config = log4rs::config::Config::builder()
        .appender(log4rs::config::Appender::builder().build("syslog", syslog))
        .appender(log4rs::config::Appender::builder().build("stdout", stdout))
        .build(
            log4rs::config::Root::builder()
                .appender("syslog")
                .appender("stdout")
                // Set the minimum logging level to record
                .build(log::LevelFilter::Debug),
        )?;

    // Start the logger
    log4rs::init_config(config)?;

    let args: Vec<String> = env::args().collect();
    let program = args[0].clone();

    let mut opts = Options::new();
    opts.optflagopt(
        "r",
        "run",
        "Run level which should be executed",
        "RUN_LEVEL",
    );
    opts.optflag("h", "help", "Print this help menu");

    let matches = match opts.parse(&args[1..]) {
        Ok(r) => r,
        Err(f) => panic!(f.to_string()),
    };

    if matches.opt_present("h") {
        let brief = format!("Usage: {} [options]", program);
        print!("{}", opts.usage(&brief));
        return Ok(());
    }

    let _uuid = env::var_os("KUBOS_APP_UUID");
    let run_level = matches
        .opt_str("r")
        .unwrap_or_else(|| "OnCommand".to_owned());

    match run_level.as_ref() {
        "OnBoot" => handler.on_boot(args),
        "OnCommand" => handler.on_command(args),
        level => {
            bail!(
                "Error: Unknown run level was requested - {}. Available run levels: OnBoot, OnCommand", level
            );
        }
    }
}