Refactor error management in API part

src/api/error.rs

@@ -0,0 +1,116 @@
+use err_derive::Error;
+use hyper::StatusCode;
+
+use garage_util::error::Error as GarageError;
+
+#[derive(Debug, Error)]
+pub enum Error {
+	// Category: internal error
+	#[error(display = "Internal error: {}", _0)]
+	InternalError(#[error(source)] GarageError),
+
+	#[error(display = "Internal error (Hyper error): {}", _0)]
+	Hyper(#[error(source)] hyper::Error),
+
+	#[error(display = "Internal error (HTTP error): {}", _0)]
+	HTTP(#[error(source)] http::Error),
+
+	// Category: cannot process
+	#[error(display = "Forbidden: {}", _0)]
+	Forbidden(String),
+
+	#[error(display = "Not found")]
+	NotFound,
+
+	// Category: bad request
+	#[error(display = "Invalid UTF-8: {}", _0)]
+	InvalidUTF8(#[error(source)] std::str::Utf8Error),
+
+	#[error(display = "Invalid XML: {}", _0)]
+	InvalidXML(#[error(source)] roxmltree::Error),
+
+	#[error(display = "Invalid header value: {}", _0)]
+	InvalidHeader(#[error(source)] hyper::header::ToStrError),
+
+	#[error(display = "Invalid HTTP range: {:?}", _0)]
+	InvalidRange(#[error(from)] http_range::HttpRangeParseError),
+
+	#[error(display = "Bad request: {}", _0)]
+	BadRequest(String),
+}
+
+impl Error {
+	pub fn http_status_code(&self) -> StatusCode {
+		match self {
+			Error::NotFound => StatusCode::NOT_FOUND,
+			Error::Forbidden(_) => StatusCode::FORBIDDEN,
+			Error::InternalError(GarageError::RPC(_)) => StatusCode::SERVICE_UNAVAILABLE,
+			Error::InternalError(_) | Error::Hyper(_) | Error::HTTP(_) => {
+				StatusCode::INTERNAL_SERVER_ERROR
+			}
+			_ => StatusCode::BAD_REQUEST,
+		}
+	}
+}
+
+pub trait OkOrBadRequest {
+	type S2;
+	fn ok_or_bad_request(self, reason: &'static str) -> Self::S2;
+}
+
+impl<T, E> OkOrBadRequest for Result<T, E>
+where
+	E: std::fmt::Display,
+{
+	type S2 = Result<T, Error>;
+	fn ok_or_bad_request(self, reason: &'static str) -> Result<T, Error> {
+		match self {
+			Ok(x) => Ok(x),
+			Err(e) => Err(Error::BadRequest(format!("{}: {}", reason, e))),
+		}
+	}
+}
+
+impl<T> OkOrBadRequest for Option<T> {
+	type S2 = Result<T, Error>;
+	fn ok_or_bad_request(self, reason: &'static str) -> Result<T, Error> {
+		match self {
+			Some(x) => Ok(x),
+			None => Err(Error::BadRequest(format!("{}", reason))),
+		}
+	}
+}
+
+pub trait OkOrInternalError {
+	type S2;
+	fn ok_or_internal_error(self, reason: &'static str) -> Self::S2;
+}
+
+impl<T, E> OkOrInternalError for Result<T, E>
+where
+	E: std::fmt::Display,
+{
+	type S2 = Result<T, Error>;
+	fn ok_or_internal_error(self, reason: &'static str) -> Result<T, Error> {
+		match self {
+			Ok(x) => Ok(x),
+			Err(e) => Err(Error::InternalError(GarageError::Message(format!(
+				"{}: {}",
+				reason, e
+			)))),
+		}
+	}
+}
+
+impl<T> OkOrInternalError for Option<T> {
+	type S2 = Result<T, Error>;
+	fn ok_or_internal_error(self, reason: &'static str) -> Result<T, Error> {
+		match self {
+			Some(x) => Ok(x),
+			None => Err(Error::InternalError(GarageError::Message(format!(
+				"{}",
+				reason
+			)))),
+		}
+	}
+}