module GRPC::Core::StatusCodes

Aborted indicates 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.

AlreadyExists means an attempt to create an entity failed because one already exists.

Canceled indicates the operation was canceled (typically by the caller).

DataLoss indicates unrecoverable data loss or corruption.

DeadlineExceeded means operation expired before completion. 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.

FailedPrecondition indicates 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.
(d) Use FailedPrecondition if the client performs conditional REST
    Get/Update/Delete on a resource and the resource on the server does
    not match the condition. E.g., conflicting read-modify-write on the
    same resource.

Internal errors. Means some invariants expected by underlying system has been broken. If you see one of these errors, something is very broken.

InvalidArgument indicates client specified an invalid argument. Note that this differs from FailedPrecondition. It indicates arguments that are problematic regardless of the state of the system (e.g., a malformed file name).

NotFound means some requested entity (e.g., file or directory) was not found.

OK is returned on success.

OutOfRange means 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.

PermissionDenied indicates the caller does not have permission to execute the specified operation. It must not be used for rejections caused by exhausting some resource (use ResourceExhausted instead for those errors). It must not be used if the caller cannot be identified (use Unauthenticated instead for those errors).

ResourceExhausted indicates some resource has been exhausted, perhaps a per-user quota, or perhaps the entire file system is out of space.

Unauthenticated indicates the request does not have valid authentication credentials for the operation.

Unavailable indicates the service is currently unavailable. This is a most likely a transient condition and may be corrected by retrying with a backoff. Note that it is not always safe to retry non-idempotent operations.

See litmus test above for deciding between FailedPrecondition, Aborted, and Unavailable.

Unimplemented indicates operation is not implemented or not supported/enabled in this service.

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.