feat: Add Status constructors (#137)

Co-Authored-By: Lucio Franco <luciofranco14@gmail.com>

tonic/src/status.rs

@@ -9,6 +9,17 @@ const GRPC_STATUS_MESSAGE_HEADER: &str = "grpc-message";
 const GRPC_STATUS_DETAILS_HEADER: &str = "grpc-status-details-bin";
 
 /// A gRPC status describing the result of an RPC call.
+///
+/// Values can be created using the `new` function or one of the specialized
+/// associated functions.
+/// ```rust
+/// # use tonic::{Status, Code};
+/// let status1 = Status::new(Code::InvalidArgument, "name is invalid");
+/// let status2 = Status::invalid_argument("name is invalid");
+///
+/// assert_eq!(status1.code(), Code::InvalidArgument);
+/// assert_eq!(status1.code(), status2.code());
+/// ```
 #[derive(Clone)]
 pub struct Status {
     /// The gRPC status code, found in the `grpc-status` header.
@@ -25,24 +36,56 @@ pub struct Status {
 ///
 /// [gRPC status codes]: https://github.com/grpc/grpc/blob/master/doc/statuscodes.md#status-codes-and-their-use-in-grpc
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
-#[allow(missing_docs)]
 pub enum Code {
+    /// The operation completed successfully.
     Ok = 0,
+
+    /// The operation was cancelled.
     Cancelled = 1,
+
+    /// Unknown error.
     Unknown = 2,
+
+    /// Client specified an invalid argument.
     InvalidArgument = 3,
+
+    /// Deadline expired before operation could complete.
     DeadlineExceeded = 4,
+
+    /// Some requested entity was not found.
     NotFound = 5,
+
+    /// Some entity that we attempted to create already exists.
     AlreadyExists = 6,
+
+    /// The caller does not have permission to execute the specified operation.
     PermissionDenied = 7,
+
+    /// Some resource has been exhausted.
     ResourceExhausted = 8,
+
+    /// The system is not in a state required for the operation's execution.
     FailedPrecondition = 9,
+
+    /// The operation was aborted.
     Aborted = 10,
+
+    /// Operation was attempted past the valid range.
     OutOfRange = 11,
+
+    /// Operation is not implemented or not supported.
     Unimplemented = 12,
+
+    /// Internal error.
     Internal = 13,
+
+    /// The service is currently unavailable.
     Unavailable = 14,
+
+    /// Unrecoverable data loss or corruption.
     DataLoss = 15,
+
+    /// The request does not have valid authentication credentials
     Unauthenticated = 16,
 
     // New Codes may be added in the future, so never exhaustively match!
@@ -62,13 +105,140 @@ impl Status {
         }
     }
 
-    /// Create a new `Unimplemented` status with the associated message.
+    /// The operation completed successfully.
+    pub fn ok(message: impl Into<String>) -> Status {
+        Status::new(Code::Ok, message)
+    }
+
+    /// The operation was cancelled (typically by the caller).
+    pub fn cancelled(message: impl Into<String>) -> Status {
+        Status::new(Code::Cancelled, message)
+    }
+
+    /// Unknown error. An example of where this error may be returned is if a
+    /// `Status` value received from another address space belongs to an error-space
+    /// that is not known in this address space. Also errors raised by APIs that
+    /// do not return enough error information may be converted to this error.
+    pub fn unknown(message: impl Into<String>) -> Status {
+        Status::new(Code::Unknown, message)
+    }
+
+    /// Client specified an invalid argument. Note that this differs from
+    /// `FailedPrecondition`. `InvalidArgument` indicates arguments that are
+    /// problematic regardless of the state of the system (e.g., a malformed file
+    /// name).
+    pub fn invalid_argument(message: impl Into<String>) -> Status {
+        Status::new(Code::InvalidArgument, message)
+    }
+
+    /// Deadline expired before operation could complete. For operations that
+    /// change the state of the system, this error may be returned even if the
+    /// operation has completed successfully. For example, a successful response
+    /// from a server could have been delayed long enough for the deadline to
+    /// expire.
+    pub fn deadline_exceeded(message: impl Into<String>) -> Status {
+        Status::new(Code::DeadlineExceeded, message)
+    }
+
+    /// Some requested entity (e.g., file or directory) was not found.
+    pub fn not_found(message: impl Into<String>) -> Status {
+        Status::new(Code::NotFound, message)
+    }
+
+    /// Some entity that we attempted to create (e.g., file or directory) already
+    /// exists.
+    pub fn already_exists(message: impl Into<String>) -> Status {
+        Status::new(Code::AlreadyExists, message)
+    }
+
+    /// The caller does not have permission to execute the specified operation.
+    /// `PermissionDenied` must not be used for rejections caused by exhausting
+    /// some resource (use `ResourceExhausted` instead for those errors).
+    /// `PermissionDenied` must not be used if the caller cannot be identified
+    /// (use `Unauthenticated` instead for those errors).
+    pub fn permission_denied(message: impl Into<String>) -> Status {
+        Status::new(Code::PermissionDenied, message)
+    }
+
+    /// Some resource has been exhausted, perhaps a per-user quota, or perhaps
+    /// the entire file system is out of space.
+    pub fn resource_exhausted(message: impl Into<String>) -> Status {
+        Status::new(Code::ResourceExhausted, message)
+    }
+
+    /// Operation was rejected because the system is not in a state required for
+    /// the operation's execution. For example, directory to be deleted may be
+    /// non-empty, an rmdir operation is applied to a non-directory, etc.
+    ///
+    /// A litmus test that may help a service implementor in deciding between
+    /// `FailedPrecondition`, `Aborted`, and `Unavailable`:
+    /// (a) Use `Unavailable` if the client can retry just the failing call.
+    /// (b) Use `Aborted` if the client should retry at a higher-level (e.g.,
+    ///     restarting a read-modify-write sequence).
+    /// (c) Use `FailedPrecondition` if the client should not retry until the
+    ///     system state has been explicitly fixed.  E.g., if an "rmdir" fails
+    ///     because the directory is non-empty, `FailedPrecondition` should be
+    ///     returned since the client should not retry unless they have first
+    ///     fixed up the directory by deleting files from it.
+    pub fn failed_precondition(message: impl Into<String>) -> Status {
+        Status::new(Code::FailedPrecondition, message)
+    }
+
+    /// The operation was aborted, typically due to a concurrency issue like
+    /// sequencer check failures, transaction aborts, etc.
+    ///
+    /// See litmus test above for deciding between `FailedPrecondition`,
+    /// `Aborted`, and `Unavailable`.
+    pub fn aborted(message: impl Into<String>) -> Status {
+        Status::new(Code::Aborted, message)
+    }
+
+    /// Operation was attempted past the valid range. E.g., seeking or reading
+    /// past end of file.
+    ///
+    /// Unlike `InvalidArgument`, this error indicates a problem that may be
+    /// fixed if the system state changes. For example, a 32-bit file system will
+    /// generate `InvalidArgument if asked to read at an offset that is not in the
+    /// range [0,2^32-1], but it will generate `OutOfRange` if asked to read from
+    /// an offset past the current file size.
+    ///
+    /// There is a fair bit of overlap between `FailedPrecondition` and
+    /// `OutOfRange`. We recommend using `OutOfRange` (the more specific error)
+    /// when it applies so that callers who are iterating through a space can
+    /// easily look for an `OutOfRange` error to detect when they are done.
+    pub fn out_of_range(message: impl Into<String>) -> Status {
+        Status::new(Code::OutOfRange, message)
+    }
+
+    /// Operation is not implemented or not supported/enabled in this service.
     pub fn unimplemented(message: impl Into<String>) -> Status {
-        Status {
-            code: Code::Unimplemented,
-            message: message.into(),
-            details: Bytes::new(),
-        }
+        Status::new(Code::Unimplemented, message)
+    }
+
+    /// Internal errors. Means some invariants expected by underlying system has
+    /// been broken. If you see one of these errors, something is very broken.
+    pub fn internal(message: impl Into<String>) -> Status {
+        Status::new(Code::Internal, message)
+    }
+
+    /// The service is currently unavailable.  This is a most likely a transient
+    /// condition and may be corrected by retrying with a back-off.
+    ///
+    /// See litmus test above for deciding between `FailedPrecondition`,
+    /// `Aborted`, and `Unavailable`.
+    pub fn unavailable(message: impl Into<String>) -> Status {
+        Status::new(Code::Unavailable, message)
+    }
+
+    /// Unrecoverable data loss or corruption.
+    pub fn data_loss(message: impl Into<String>) -> Status {
+        Status::new(Code::DataLoss, message)
+    }
+
+    /// The request does not have valid authentication credentials for the
+    /// operation.
+    pub fn unauthenticated(message: impl Into<String>) -> Status {
+        Status::new(Code::Unauthenticated, message)
     }
 
     #[cfg_attr(not(feature = "h2"), allow(dead_code))]
@@ -505,4 +675,31 @@ mod tests {
         assert_eq!(Code::from(-1), Code::Unknown);
         assert_eq!(Code::from(Code::__NonExhaustive as i32), Code::Unknown);
     }
+
+    #[test]
+    fn constructors() {
+        assert_eq!(Status::ok("").code(), Code::Ok);
+        assert_eq!(Status::cancelled("").code(), Code::Cancelled);
+        assert_eq!(Status::unknown("").code(), Code::Unknown);
+        assert_eq!(Status::invalid_argument("").code(), Code::InvalidArgument);
+        assert_eq!(Status::deadline_exceeded("").code(), Code::DeadlineExceeded);
+        assert_eq!(Status::not_found("").code(), Code::NotFound);
+        assert_eq!(Status::already_exists("").code(), Code::AlreadyExists);
+        assert_eq!(Status::permission_denied("").code(), Code::PermissionDenied);
+        assert_eq!(
+            Status::resource_exhausted("").code(),
+            Code::ResourceExhausted
+        );
+        assert_eq!(
+            Status::failed_precondition("").code(),
+            Code::FailedPrecondition
+        );
+        assert_eq!(Status::aborted("").code(), Code::Aborted);
+        assert_eq!(Status::out_of_range("").code(), Code::OutOfRange);
+        assert_eq!(Status::unimplemented("").code(), Code::Unimplemented);
+        assert_eq!(Status::internal("").code(), Code::Internal);
+        assert_eq!(Status::unavailable("").code(), Code::Unavailable);
+        assert_eq!(Status::data_loss("").code(), Code::DataLoss);
+        assert_eq!(Status::unauthenticated("").code(), Code::Unauthenticated);
+    }
 }