scopedb-client 0.2.1

// Copyright 2024 ScopeDB, Inc.
//
// 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.

use std::fmt;

use crate::protocol::AppendErrorDetails;

/// ErrorKind is all kinds of Error of ScopeDB client.
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
#[non_exhaustive]
pub enum ErrorKind {
    /// The client don't know what happened here, and no actions other than just
    /// returning it back.
    Unexpected,

    /// The config for ScopeDB client is invalid.
    ConfigInvalid,

    /// A table append was rejected or its commit outcome is unknown.
    AppendRowsFailed,
}

impl ErrorKind {
    /// Convert self into static str.
    pub fn into_static(self) -> &'static str {
        self.into()
    }
}

impl fmt::Display for ErrorKind {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "{}", self.into_static())
    }
}

impl From<ErrorKind> for &'static str {
    fn from(v: ErrorKind) -> &'static str {
        match v {
            ErrorKind::Unexpected => "Unexpected",
            ErrorKind::ConfigInvalid => "ConfigInvalid",
            ErrorKind::AppendRowsFailed => "AppendRowsFailed",
        }
    }
}

#[derive(Clone, Copy, Debug, PartialEq, Eq)]
enum ErrorStatus {
    /// Permanent means without external changes, the error never changes.
    ///
    /// For example, underlying services returns a not found error.
    ///
    /// Users SHOULD never retry this operation.
    Permanent,
    /// Temporary means this error is returned for temporary.
    ///
    /// For example, underlying services is rate limited or unavailable for temporary.
    ///
    /// Users CAN retry the operation to resolve it.
    Temporary,
    /// Persistent means this error used to be temporary but still failed after retry.
    ///
    /// For example, underlying services kept returning network errors.
    ///
    /// Users MAY retry this operation, but it's highly possible to error again.
    Persistent,
}

impl fmt::Display for ErrorStatus {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            ErrorStatus::Permanent => write!(f, "permanent"),
            ErrorStatus::Temporary => write!(f, "temporary"),
            ErrorStatus::Persistent => write!(f, "persistent"),
        }
    }
}

pub struct Error {
    kind: ErrorKind,
    message: String,

    status: ErrorStatus,
    context: Vec<(&'static str, String)>,
    append_details: Option<AppendErrorDetails>,

    source: Option<anyhow::Error>,
}

impl fmt::Display for Error {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "{} ({})", self.kind, self.status)?;

        if !self.context.is_empty() {
            write!(f, ", context: {{ ")?;
            write!(
                f,
                "{}",
                self.context
                    .iter()
                    .map(|(k, v)| format!("{k}: {v}"))
                    .collect::<Vec<_>>()
                    .join(", ")
            )?;
            write!(f, " }}")?;
        }

        if !self.message.is_empty() {
            write!(f, " => {}", self.message)?;
        }

        if let Some(source) = &self.source {
            write!(f, ", source: {source}")?;
        }

        Ok(())
    }
}

impl fmt::Debug for Error {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        // If alternate has been specified, we will print like Debug.
        if f.alternate() {
            let mut de = f.debug_struct("Error");
            de.field("kind", &self.kind);
            de.field("message", &self.message);
            de.field("status", &self.status);
            de.field("context", &self.context);
            de.field("append_details", &self.append_details);
            de.field("source", &self.source);
            return de.finish();
        }

        write!(f, "{} ({})", self.kind, self.status)?;
        if !self.message.is_empty() {
            write!(f, " => {}", self.message)?;
        }
        writeln!(f)?;

        if !self.context.is_empty() {
            writeln!(f)?;
            writeln!(f, "Context:")?;
            for (k, v) in self.context.iter() {
                writeln!(f, "   {k}: {v}")?;
            }
        }
        if let Some(source) = &self.source {
            writeln!(f)?;
            writeln!(f, "Source:")?;
            writeln!(f, "   {source:#}")?;
        }

        Ok(())
    }
}

impl std::error::Error for Error {
    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
        self.source.as_ref().map(|v| v.as_ref())
    }
}

impl Error {
    /// Create a new Error with error kind and message.
    pub fn new(kind: ErrorKind, message: impl Into<String>) -> Self {
        Self {
            kind,
            message: message.into(),

            status: ErrorStatus::Permanent,
            context: Vec::default(),
            append_details: None,
            source: None,
        }
    }

    /// Add more context in error.
    pub fn with_context(mut self, key: &'static str, value: impl ToString) -> Self {
        self.context.push((key, value.to_string()));
        self
    }

    /// Set source for error.
    ///
    /// # Notes
    ///
    /// If the source has been set, we will raise a panic here.
    pub fn set_source(mut self, src: impl Into<anyhow::Error>) -> Self {
        debug_assert!(self.source.is_none(), "the source error has been set");

        self.source = Some(src.into());
        self
    }

    /// Return structured table-append failure details, when available.
    pub fn append_details(&self) -> Option<&AppendErrorDetails> {
        self.append_details.as_ref()
    }

    pub(crate) fn set_append_details(mut self, details: AppendErrorDetails) -> Self {
        self.append_details = Some(details);
        self
    }

    /// Set permanent status for error.
    pub fn set_permanent(mut self) -> Self {
        self.status = ErrorStatus::Permanent;
        self
    }

    /// Set temporary status for error.
    ///
    /// By set temporary, we indicate this error is retryable.
    pub fn set_temporary(mut self) -> Self {
        self.status = ErrorStatus::Temporary;
        self
    }

    /// Set persistent status for error.
    ///
    /// By setting persistent, we indicate the retry should be stopped.
    pub fn set_persistent(mut self) -> Self {
        self.status = ErrorStatus::Persistent;
        self
    }

    /// Return the kind of this error.
    pub fn kind(&self) -> ErrorKind {
        self.kind
    }

    /// Return the error message.
    pub fn message(&self) -> &str {
        &self.message
    }

    /// Check if this error is temporary.
    pub fn is_temporary(&self) -> bool {
        self.status == ErrorStatus::Temporary
    }

    /// Check if this error is permanent.
    pub fn is_permanent(&self) -> bool {
        self.status == ErrorStatus::Permanent
    }

    /// Check if this error is persistent.
    pub fn is_persistent(&self) -> bool {
        self.status == ErrorStatus::Persistent
    }
}