drogue-bazaar 0.3.0

mod main;

pub use main::*;

use crate::app::init::{self, Tracing};
use crate::core::{config::ConfigFromEnv, info::ComponentInformation};
use crate::{app::health::HealthServerConfig, core::Spawner, health::HealthChecked};
use std::future::Future;
use std::io::Write;
use std::pin::Pin;
use std::time::Duration;

#[derive(Clone, Debug, Default, serde::Deserialize)]
pub struct RuntimeConfig {
    #[serde(default)]
    pub console_metrics: ConsoleMetrics,
    #[serde(default)]
    pub health: HealthServerConfig,
    #[serde(default)]
    pub tracing: Tracing,
}

#[derive(Clone, Debug, serde::Deserialize)]
pub struct ConsoleMetrics {
    pub enabled: bool,
    #[serde(
        default = "default::console_metrics_duration",
        with = "humantime_serde"
    )]
    pub period: Duration,
}

impl Default for ConsoleMetrics {
    fn default() -> Self {
        Self {
            enabled: false,
            period: default::console_metrics_duration(),
        }
    }
}

mod default {
    use super::*;

    pub const fn console_metrics_duration() -> Duration {
        Duration::from_secs(60)
    }
}

pub struct Runtime {
    component: ComponentInformation,
    dotenv: Option<bool>,
    show_banner: Option<bool>,
}

/// Create a new runtime, using the local crate as component.
///
/// ```
/// use drogue_bazaar::{project, runtime, app::{Main, Startup}};
///
/// project!(PROJECT: "Drogue IoT");
///
/// #[derive(serde::Deserialize)]
/// struct Config {}
///
/// async fn run(config: Config, startup: &mut dyn Startup) -> anyhow::Result<()> {
///     Ok(())
/// }
///
/// fn main() {
///     let runtime = runtime!(PROJECT)
///         .exec(run);
/// }
/// ```
#[macro_export]
macro_rules! runtime {
    ($project:expr) => {
        $crate::app::Runtime::new($crate::component!($project))
    };
}

impl Runtime {
    pub fn new(component: ComponentInformation) -> Self {
        Self {
            component,
            dotenv: None,
            show_banner: None,
        }
    }

    /// Force dotenv option.
    ///
    /// ```
    /// use drogue_bazaar::{project, runtime};
    ///
    /// project!(PROJECT: "Drogue IoT");
    ///
    /// fn main() {
    ///     runtime!(PROJECT)
    ///         .dotenv(false);
    /// }
    /// ```
    #[allow(clippy::needless_doctest_main)]
    pub fn dotenv<I: Into<Option<bool>>>(mut self, dotenv: I) -> Self {
        self.dotenv = dotenv.into();
        self
    }

    /// Show the application banner
    fn banner(&self) {
        if self
            .show_banner
            .or_else(|| flag_opt("RUNTIME__SHOW_BANNER"))
            .unwrap_or(true)
        {
            println!(
                r#"{}  
{} {} - {} {} ({})
"#,
                self.component.project.banner,
                self.component.project.name,
                self.component.project.version,
                self.component.name,
                self.component.version,
                self.component.description
            );

            std::io::stdout().flush().ok();
        }
    }

    pub async fn exec<C, A>(self, app: A) -> anyhow::Result<()>
    where
        A: App<C>,
        for<'de> C: ConfigFromEnv<'de>,
    {
        // phase 1: early init, cannot really rely on env-vars, but may add its own

        init::phase1(
            self.dotenv
                .unwrap_or_else(|| !flag("RUNTIME__DISABLE_DOTENV")),
        );

        // phase 2: Show early runtime information
        self.banner();

        // phase 3: env-vars are ready now, we can make use of them

        let mut main = Main::from_env()?;
        init::phase2(self.component.name, main.runtime_config().tracing.clone());

        // phase 4: main app startup

        let config = C::from_env()?;
        app.run(config, &mut main).await?;
        main.run().await?;

        // exiting, shutdown tracing (flush)
        opentelemetry::global::shutdown_tracer_provider();

        // done

        Ok(())
    }

    pub async fn exec_fn<C, F>(self, f: F) -> anyhow::Result<()>
    where
        for<'de> C: ConfigFromEnv<'de> + Send + 'static,
        F: for<'f> AppFn<C, &'f mut dyn Startup>,
    {
        self.exec(f).await
    }
}

pub trait AppFn<C, S>: FnOnce(C, S) -> <Self as AppFn<C, S>>::Fut {
    type Fut: Future<Output = anyhow::Result<()>>;
}

impl<C, S, F, Fut> AppFn<C, S> for F
where
    F: FnOnce(C, S) -> Fut,
    Fut: Future<Output = anyhow::Result<()>>,
{
    type Fut = Fut;
}

#[async_trait::async_trait(?Send)]
pub trait App<C>
where
    for<'de> C: ConfigFromEnv<'de>,
{
    async fn run(self, config: C, startup: &mut dyn Startup) -> anyhow::Result<()>;
}

#[async_trait::async_trait(?Send)]
impl<C, A> App<C> for A
where
    A: for<'f> AppFn<C, &'f mut dyn Startup>,
    C: for<'de> ConfigFromEnv<'de> + 'static,
{
    async fn run(self, config: C, startup: &mut dyn Startup) -> anyhow::Result<()> {
        (self)(config, startup).await
    }
}

fn flag(name: &str) -> bool {
    flag_opt(name).unwrap_or_default()
}

fn flag_opt(name: &str) -> Option<bool> {
    std::env::var(name).map(|v| v.to_lowercase() == "true").ok()
}

/// Startup context.
pub trait Startup: Spawner {
    /// Add a health check.
    fn check_boxed(&mut self, check: Box<dyn HealthChecked>);

    /// Allow the application to check if the runtime wants to enable tracing.
    ///
    /// This can be used to e.g. add some tracing logger into the HTTP stack.
    fn use_tracing(&self) -> bool;

    /// Access the runtime config.
    fn runtime_config(&self) -> &RuntimeConfig;
}

pub trait StartupExt: Startup {
    /// Add several health checks at once.
    fn check_iter<I>(&mut self, iter: I)
    where
        I: IntoIterator<Item = Box<dyn HealthChecked>>,
    {
        for i in iter {
            self.check_boxed(i);
        }
    }

    fn check<C>(&mut self, c: C)
    where
        C: HealthChecked + 'static,
    {
        self.check_boxed(Box::new(c))
    }

    fn spawn_iter<I>(&mut self, iter: I)
    where
        I: IntoIterator<Item = Pin<Box<dyn Future<Output = anyhow::Result<()>>>>>,
    {
        for i in iter {
            self.spawn_boxed(i);
        }
    }

    fn spawn<F>(&mut self, f: F)
    where
        F: Future<Output = anyhow::Result<()>> + 'static,
    {
        self.spawn_boxed(Box::pin(f))
    }
}

impl<S: ?Sized> StartupExt for S where S: Startup {}