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
//! Trait for representing an Abscissa application and it's lifecycle
pub mod cell;
pub(crate) mod exit;
pub mod lock;
mod name;
mod state;
pub use self::{cell::AppCell, exit::fatal_error, lock::Lock, name::Name, state::State};
#[cfg(all(feature = "signals", unix))]
use crate::signal::Signal;
use crate::{
command::Command,
component::Component,
config::{Config, Configurable},
path::{AbsPathBuf, ExePath, RootPath},
runnable::Runnable,
shutdown::Shutdown,
terminal::{component::Terminal, ColorChoice},
trace::{self, Tracing},
FrameworkError,
FrameworkErrorKind::*,
Version,
};
use std::{env, path::Path, process, vec};
/// Application types implementing this trait own global application state,
/// including configuration and arbitrary other values stored within
/// application components.
///
/// Application lifecycle is handled by a set of components owned by types
/// implementing this trait. It also ties together the following:
///
/// - `Cmd`: application entrypoint
/// - `Config `: application configuration
/// - `Paths`: paths to various resources within the application
#[allow(unused_variables)]
pub trait Application: Default + Sized + 'static {
/// Application (sub)command which serves as the main entry point.
type Cmd: Command + Configurable<Self::Cfg>;
/// Configuration type used by this application.
type Cfg: Config;
/// Paths to application resources,
type Paths: Default + ExePath + RootPath;
/// Run application with the given command-line arguments and running the
/// appropriate `Command` type.
fn run<I>(app_cell: &'static AppCell<Self>, args: I)
where
I: IntoIterator<Item = String>,
{
// Parse command line options
let command = Self::Cmd::from_args(args);
// Initialize application
let mut app = Self::default();
app.init(&command).unwrap_or_else(|e| fatal_error(&app, &e));
app_cell.set_once(app);
// Run the command
command.run();
// Exit gracefully
let mut app = app_cell.write();
app.shutdown(Shutdown::Graceful);
}
/// Accessor for application configuration.
fn config(&self) -> &Self::Cfg;
/// Borrow the application state immutably.
fn state(&self) -> &State<Self>;
/// Borrow the application state mutably.
fn state_mut(&mut self) -> &mut State<Self>;
/// Register all components used by this application
fn register_components(&mut self, command: &Self::Cmd) -> Result<(), FrameworkError>;
/// 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.
///
/// This method is responsible for invoking the `after_config` handlers on
/// all components in the registry. This is presently done in the standard
/// application template, but is not otherwise handled directly by the
/// framework (as ownership precludes it).
fn after_config(&mut self, config: Self::Cfg) -> Result<(), FrameworkError>;
/// 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)?;
// Load configuration
let config = command
.config_path()
.map(|path| self.load_config(&path))
.transpose()?
.unwrap_or_default();
// Fire callback regardless of whether any config was loaded to
// in order to signal state in the application lifecycle
self.after_config(command.process_config(config)?)?;
Ok(())
}
/// Initialize the framework's default set of components, potentially
/// sourcing terminal and tracing options from command line arguments.
fn framework_components(
&mut self,
command: &Self::Cmd,
) -> Result<Vec<Box<dyn Component<Self>>>, FrameworkError> {
let terminal = Terminal::new(self.term_colors(command));
let tracing = Tracing::new(self.tracing_config(command), self.term_colors(command))
.expect("tracing subsystem failed to initialize");
Ok(vec![Box::new(terminal), Box::new(tracing)])
}
/// Load configuration from the given path.
///
/// Returns an error if the configuration could not be loaded.
fn load_config(&mut self, path: &Path) -> Result<Self::Cfg, FrameworkError> {
let canonical_path = AbsPathBuf::canonicalize(path).map_err(|e| {
let path_error = PathError {
name: Some(path.into()),
};
FrameworkError::from(ConfigError.context(path_error))
})?;
Self::Cfg::load_toml_file(&canonical_path)
}
/// Name of this application as a string.
fn name(&self) -> &'static str {
Self::Cmd::name()
}
/// Description of this application.
fn description(&self) -> &'static str {
Self::Cmd::description()
}
/// Version of this application.
fn version(&self) -> Version {
Self::Cmd::version()
.parse::<Version>()
.unwrap_or_else(|e| fatal_error(self, &e))
}
/// Authors of this application.
fn authors(&self) -> Vec<String> {
Self::Cmd::authors().split(':').map(str::to_owned).collect()
}
/// Color configuration for this application.
fn term_colors(&self, command: &Self::Cmd) -> ColorChoice {
ColorChoice::Auto
}
/// Get the tracing configuration for this application.
fn tracing_config(&self, command: &Self::Cmd) -> trace::Config {
trace::Config::default()
}
/// Handle a Unix signal received by this application
#[cfg(all(feature = "signals", unix))]
fn handle_signal(&mut self, signal: Signal) -> Result<(), FrameworkError> {
info!("received signal: {} - shutting down", signal.number());
self.shutdown(Shutdown::Graceful)
}
/// Shut down this application gracefully, exiting with success.
fn shutdown(&mut self, shutdown: Shutdown) -> ! {
if let Err(e) = self.state().components.shutdown(self, shutdown) {
fatal_error(self, &e)
}
process::exit(0);
}
}
/// Boot the given application, parsing subcommand and options from
/// command-line arguments, and terminating when complete.
pub fn boot<A: Application>(app_cell: &'static AppCell<A>) -> ! {
let mut args = env::args();
assert!(args.next().is_some(), "expected one argument but got zero");
A::run(app_cell, args);
process::exit(0);
}