tag2upload_service_manager/

error.rs

use crate::prelude::*;
use std::backtrace::Backtrace;

#[derive(Error, Debug)]
pub enum ProcessingError {
    #[error("problem at forge: {0:#}")]
    Forge(anyhow::Error),

    #[error("local problem {0:#}")]
    Local(anyhow::Error),

    #[error("{0}")]
    Mismatch(#[from] MismatchError),

    #[error("{0}")]
    Internal(#[from] InternalError),
}

/// Token indicating that we are OK to shut this task down
///
/// Returned by the closure passed to [`Globals::spawn-task`].
///
/// Not an error.
pub struct TaskWorkComplete {}

/// Not an `Error`
#[derive(Debug, From)]
pub enum QuitTask {
    Crashed(InternalError),
    Shutdown(ShuttingDown),
}

pub type TaskResult = Result<TaskWorkComplete, QuitTask>;

#[derive(Error, Debug)]
pub enum StartupError {
    #[error("failed to parse/deserialise t2u configuration: {0}")]
    ParseConfig(figment::Error),

    #[error("invalid configuration")]
    InvalidConfig,

    #[error("problem with temp directory: {0:#}")]
    TempDir(AE),

    #[error("failed to initialise http client: {0}")]
    Reqwest(#[from] reqwest::Error),

    #[error("failed to initialise DNS resolver: {0}")]
    Resolver(#[from] hickory_resolver::ResolveError),

    #[error("failed to initialise Rocket http server: {0}")]
    Rocket(#[from] rocket::Error),

    #[error("failed to initialise worker listener(s): {0:#}")]
    WorkerListener(AE),

    #[error("failed to open database: {0}")]
    DbOpen(rusqlite::Error),

    #[error("failed to idempotently initialise db schema: {0}")]
    ExecuteSchema(rusqlite::Error),

    #[error("failed to access database during startup: {0}")]
    DbAccess(rusqlite::Error),

    #[error("failed to initialise logging: {0:#}")]
    Logging(AE),

    #[error("failed to initialise templates from explcit dir: {0:#}")]
    Templates(#[source] AE),

    #[error("internal error during startup: {0}")]
    Internal(#[from] InternalError),
}

#[derive(Error, Debug)]
pub enum NotForUsReason {
    #[error("unexpected/incomplete JSON payload: {0}")]
    DeserFailed(String),

    #[error("webhook event is tag being deleted")]
    TagIsBeingDeleted,

    #[error("tag name has unexpected syntax (not DEP-14)")]
    TagNameUnexpectedSyntax,

    #[error("tag name doesn't start with our DEP-14 distro name")]
    TagNameNotOurDistro,

    #[error("tag message has only summary/title, no body")]
    TagWithoutMessageBody,

    #[error("no [dgit please-upload] instruction")]
    NoPleaseUpload,

    #[error("missing [dgit source= ] information (old git-debpush?)")]
    MissingSource,

    #[error("missing [dgit version= ] information (old git-debpush?)")]
    MissingVersion,

    #[error("no [dgit distro=...] for the distro we support")]
    MetaNotOurDistro,

    #[error("bad metadata item: {item:?}: {error}")]
    BadMetadataItem { item: String, error: MetadataItemError, },

    #[error("source package not mentioned in passlist")]
    PackageNotPasslisted,

    #[error("tag is too old ({age} > {max})")]
    TagTooOld {
        age: humantime::Duration,
        max: humantime::Duration,
    },

    #[error("tag is too new by {skew} (> {max})")]
    TagTooNew {
        skew: humantime::Duration,
        max: humantime::Duration,
    },
}

#[derive(Error, Debug)]
pub enum WebError {
    #[error("misconfigured (or malfunctioning) web hook: {0:#}")]
    MisconfiguredWebhook(AE),
    #[error("{0}")]
    InternalError(#[from] InternalError),
    #[error("tag is not for us: {0}")]
    NotForUs(#[from] NotForUsReason),
    #[error("page not found at this URL: {0:#}")]
    PageNotFoundHere(AE),
    #[error("{0}")]
    DisallowedClient(#[from] dns::DisallowedClient),
    #[error("service throttled: {0}")]
    Throttled(String),
}

#[derive(Error, Debug)]
pub enum OracleTaskError {
    #[error("oracle disconnected")]
    Disconnected,

    #[error("I/O error on oracle connection")]
    Io(Arc<io::Error>),

    #[error("malformed message received: {0}")]
    BadMessage(#[from] o2m_support::BadMessage),

    #[error("peer reported protocol violation: {0}")]
    PeerReportedProtocolViolation(#[from] o2m_messages::ProtocolViolation),

    #[error("peer requested protocol version {}; not supported", .0.version)]
    UnsupportedVersion(o2m_messages::VersionRequest),

    #[error("maximum line length (`limits.o2m_line`) exceeded")]
    MaxLineLengthExceeded,

    #[error("{0}")]
    InternalError(#[from] InternalError),

    #[error("shutting down")]
    Shutdown(ShuttingDown),

    #[error("restarting old worker")]
    RestartingWorker,
}


#[derive(Error, Debug)]
#[error("mismatch (possible race): {what}: earlier={earlier:?} now={now:?}")]
pub struct MismatchError {
    what: String,
    earlier: String,
    now: String,
}

//==================== impls ====================

impl MismatchError {
    pub fn check<'t, T: Display + Eq>(
        what: impl Display,
        earlier: &'t T,
        now: &'t T,
    ) -> Result<&'t T, MismatchError> {
        if earlier == now {
            Ok(earlier)
        } else {
            Err(MismatchError {
                what: what.to_string(),
                earlier: earlier.to_string(),
                now: now.to_string(),
            })
        }
    }
}

impl WebError {
    fn http_status(&self) -> rocket::http::Status {
        use rocket::http::Status as S;
        match self {
            WE::MisconfiguredWebhook(_) => S::BadRequest,
            WE::InternalError(_) => S::InternalServerError,
            WE::PageNotFoundHere(_) => S::NotFound,
            WE::NotForUs { .. } => S::Ok,
            WE::Throttled(..) => S::ServiceUnavailable,
            WE::DisallowedClient(dc) => dc.http_status(),
        }
    }
}

impl<'r, 'o: 'r> rocket::response::Responder<'r, 'o> for WebError {
    fn respond_to(
        self,
        _req: &'r rocket::request::Request<'_>,
    ) -> rocket::response::Result<'o> {
        let msg = format!("error: {self}");
        Ok(rocket::response::Response::build()
           .status(self.http_status())
           .sized_body(None, Cursor::new(msg))
           .header(rocket::http::ContentType::Text)
           .finalize())
    }
}

//==================== internal error ===================

/// Internal error
///
/// Invariant: if one of these exists, it has been logged
/// already, and shutdown has been triggered.
#[derive(Error, Debug, Clone)]
// Display impl doesn't print the Backtrace; we do that on creation, only.
#[error("internal error: {:#}", self.0.ae)]
pub struct InternalError(Arc<InternalErrorPayload>);

#[derive(derive_more::Display, Debug)]
#[display("{ae:#}\n{backtrace}")]
struct InternalErrorPayload {
    ae: anyhow::Error,
    backtrace: Backtrace,
}

macro_rules! internal { { $fmt:literal $($rest:tt)* } => {
    IE::new(anyhow!($fmt $($rest)*))
} }

impl InternalError {
    #[track_caller]
    pub fn new(ae: AE) -> InternalError {
        IE::new_inner(ae, Backtrace::force_capture())
    }

    pub fn new_without_backtrace(ae: AE) -> InternalError {
        IE::new_inner(ae, Backtrace::disabled())
    }

    /// Make an `InternalError` that doesn't cause shutdown
    ///
    /// Nor does it produce a backtrace
    pub fn new_quiet(ae: AE) -> InternalError {
        let backtrace = Backtrace::disabled();
        error!("internal error - but carrying on! {ae:#}");
        let pl = InternalErrorPayload { ae, backtrace };
        InternalError(pl.into())
    }

    /// Dispose of an `InternalError` that can't be reported
    ///
    /// The error will still be logged, and will still cause shutdown.
    pub fn note_only(self) {
        // Logging and shutdown are done in construction
    }

    #[track_caller]
    fn new_inner(ae: AE, backtrace: Backtrace) -> InternalError {
        let pl = InternalErrorPayload { ae, backtrace };
        let ie = InternalError(pl.into());

        #[cfg(test)]
        test::internal_error_hook(&ie);

        globals().state.send_modify(|state| {
            state.note_internal_error_inner(ie.clone())
        });
        ie
    }

    #[cfg(test)]
    pub fn display_with_backtrace(&self) -> &impl Display { &self.0 }
}

impl global::State {
    fn note_internal_error_inner(&mut self, ie: InternalError) {
        let pl = &ie.0;
        let store = match &mut self.shutdown_reason {
            reason @ None => {
                error!("internal error, will shut down! {pl}");
                Some(reason)
            }
            reason @ Some(Ok(ShuttingDown)) => {
                error!("internal error during shutdown! {pl}");
                Some(reason)
            }
            _already @ Some(Err(_)) => {
                info!("additional internal error! {pl}");
                None
            }
        };
        if let Some(store) = store {
            *store = Some(Err(ie));
        }
    }
}

pub trait IntoInternal: Sized {
    #[track_caller]
    // TODO this API forces a lot of consing of error msgs on success paths
    fn into_internal(self, what: impl Display)
                     -> InternalError;
}
impl<E> IntoInternal for E where anyhow::Error: From<E> {
    #[track_caller]
    fn into_internal(self, what: impl Display)
                     -> InternalError {
        let what = what.to_string();
        IE::new(anyhow::Error::from(self).context(what))
    }
}

#[ext(IntoInternalResult)]
pub impl<T, E: IntoInternal> Result<T, E> {
    #[track_caller]
    fn into_internal(self, what: impl Display)
                         -> Result<T, InternalError> {
        self.map_err(move |e| e.into_internal(what))
    }
}
#[ext(IntoInternalOption)]
pub impl<T> Option<T> {
    #[track_caller]
    fn ok_or_internal(self, what: impl Display)
                         -> Result<T, InternalError> {
        self.ok_or_else(|| IE::new(anyhow!(what.to_string())))
    }
}

impl InternalError {
    // Everything should be implemented, so this shouldn't be called in prod.
    // We retain it in case we need it again.
    // Marking it #[cfg(test)] means it will get compiled.
    // When adding a real call site, add a blocking TODO of some kind.
    #[cfg(test)]
    pub fn nyi(what: &str) -> InternalError {
        // Construct *without* going through IE::new.
        // So this doesn't cause
        //  (a) shutdown
        //  (b) test failures
        let ae = anyhow!("not yet implemented")
                .context(what.to_string());
        IE::new_quiet(ae)
    }
}