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
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
//! Zebrad Abscissa Application

use crate::{commands::ZebradCmd, components::tracing::Tracing, config::ZebradConfig};
use abscissa_core::{
    application::{self, AppCell},
    config,
    config::Configurable,
    terminal::component::Terminal,
    Application, Component, EntryPoint, FrameworkError, Shutdown, StandardPaths,
};
use application::fatal_error;
use std::process;

/// Application state
pub static APPLICATION: AppCell<ZebradApp> = AppCell::new();

/// Obtain a read-only (multi-reader) lock on the application state.
///
/// Panics if the application state has not been initialized.
pub fn app_reader() -> application::lock::Reader<ZebradApp> {
    APPLICATION.read()
}

/// Obtain an exclusive mutable lock on the application state.
pub fn app_writer() -> application::lock::Writer<ZebradApp> {
    APPLICATION.write()
}

/// Obtain a read-only (multi-reader) lock on the application configuration.
///
/// Panics if the application configuration has not been loaded.
pub fn app_config() -> config::Reader<ZebradApp> {
    config::Reader::new(&APPLICATION)
}

/// Zebrad Application
#[derive(Debug)]
pub struct ZebradApp {
    /// Application configuration.
    config: Option<ZebradConfig>,

    /// Application state.
    state: application::State<Self>,
}

/// Initialize a new application instance.
///
/// By default no configuration is loaded, and the framework state is
/// initialized to a default, empty state (no components, threads, etc).
impl Default for ZebradApp {
    fn default() -> Self {
        Self {
            config: None,
            state: application::State::default(),
        }
    }
}

impl Application for ZebradApp {
    /// Entrypoint command for this application.
    type Cmd = EntryPoint<ZebradCmd>;

    /// Application configuration.
    type Cfg = ZebradConfig;

    /// Paths to resources within the application.
    type Paths = StandardPaths;

    /// Accessor for application configuration.
    fn config(&self) -> &ZebradConfig {
        self.config.as_ref().expect("config not loaded")
    }

    /// Borrow the application state immutably.
    fn state(&self) -> &application::State<Self> {
        &self.state
    }

    /// Borrow the application state mutably.
    fn state_mut(&mut self) -> &mut application::State<Self> {
        &mut self.state
    }

    /// Returns the framework components used by this application.
    fn framework_components(
        &mut self,
        command: &Self::Cmd,
    ) -> Result<Vec<Box<dyn Component<Self>>>, FrameworkError> {
        let terminal = Terminal::new(self.term_colors(command));
        // This MUST happen after `Terminal::new` to ensure our preferred panic
        // handler is the last one installed
        color_eyre::config::HookBuilder::default()
            .issue_url(concat!(env!("CARGO_PKG_REPOSITORY"), "/issues/new"))
            .add_issue_metadata("version", env!("CARGO_PKG_VERSION"))
            .issue_filter(|kind| match kind {
                color_eyre::ErrorKind::NonRecoverable(_) => true,
                color_eyre::ErrorKind::Recoverable(error) => {
                    !error.is::<tower::timeout::error::Elapsed>()
                }
            })
            .install()
            .unwrap();

        Ok(vec![Box::new(terminal)])
    }

    /// Register all components used by this application.
    ///
    /// If you would like to add additional components to your application
    /// beyond the default ones provided by the framework, this is the place
    /// to do so.
    fn register_components(&mut self, command: &Self::Cmd) -> Result<(), FrameworkError> {
        use crate::components::{
            metrics::MetricsEndpoint, tokio::TokioComponent, tracing::TracingEndpoint,
        };

        let mut components = self.framework_components(command)?;

        // Load config *after* framework components so that we can
        // report an error to the terminal if it occurs.
        let config = command
            .config_path()
            .map(|path| self.load_config(&path))
            .transpose()?
            .unwrap_or_default();

        let config = command.process_config(config)?;
        self.config = Some(config);

        let cfg_ref = self
            .config
            .as_ref()
            .expect("config is loaded before register_components");

        let default_filter = if command.verbose { "debug" } else { "info" };
        let is_server = command
            .command
            .as_ref()
            .map(ZebradCmd::is_server)
            .unwrap_or(false);

        // Launch network endpoints for long-running commands
        if is_server {
            let filter = cfg_ref.tracing.filter.as_deref().unwrap_or(default_filter);
            let flame_root = cfg_ref.tracing.flamegraph.as_deref();
            components.push(Box::new(Tracing::new(filter, flame_root)?));
            components.push(Box::new(TokioComponent::new()?));
            components.push(Box::new(TracingEndpoint::new(cfg_ref)?));
            components.push(Box::new(MetricsEndpoint::new(cfg_ref)?));
        } else {
            components.push(Box::new(Tracing::new(default_filter, None)?));
        }

        self.state.components.register(components)
    }

    /// Load this application's configuration and initialize its components.
    fn init(&mut self, command: &Self::Cmd) -> Result<(), FrameworkError> {
        // Create and register components with the application.
        // We do this first to calculate a proper dependency ordering before
        // application configuration is processed
        self.register_components(command)?;

        let config = self.config.take().unwrap();

        // Fire callback regardless of whether any config was loaded to
        // in order to signal state in the application lifecycle
        self.after_config(config)?;

        Ok(())
    }

    /// Post-configuration lifecycle callback.
    ///
    /// Called regardless of whether config is loaded to indicate this is the
    /// time in app lifecycle when configuration would be loaded if
    /// possible.
    fn after_config(&mut self, config: Self::Cfg) -> Result<(), FrameworkError> {
        // Configure components
        self.state.components.after_config(&config)?;
        self.config = Some(config);

        Ok(())
    }

    fn shutdown(&mut self, shutdown: Shutdown) -> ! {
        if let Err(e) = self.state().components.shutdown(self, shutdown) {
            fatal_error(self, &e)
        }

        // Swap out a fake app so we can trigger the destructor on the original
        let _ = std::mem::take(self);

        match shutdown {
            Shutdown::Graceful => process::exit(0),
            Shutdown::Forced => process::exit(1),
            Shutdown::Crash => process::exit(2),
        }
    }
}