gRPC 9 FAILED_PRECONDITION vs 16 UNAUTHENTICATED
Both gRPC 9 (FAILED_PRECONDITION) and 16 (UNAUTHENTICATED) belong to the gRPC Status Codes category. 9 indicates that the operation was rejected because the system is not in a state required for the operation's execution. For example, deleting a non-empty directory. Meanwhile, 16 means that the request does not have valid authentication credentials for the operation.
説明
The operation was rejected because the system is not in a state required for the operation's execution. For example, deleting a non-empty directory.
このコードが表示される場合
The request is valid on its own, but the system's current state doesn't allow it — like trying to delete a non-empty directory or update a resource that has been modified concurrently.
解決方法
Bring the system into the required state before retrying. For example, empty the directory first, or re-read the resource to get the latest version before updating.
説明
The request does not have valid authentication credentials for the operation.
このコードが表示される場合
No credentials were provided, or the provided token/certificate is expired or invalid. Different from PERMISSION_DENIED (code 7), which means authenticated but not authorized.
解決方法
Provide valid authentication credentials (e.g., refresh the OAuth token, regenerate the API key, or renew the client certificate).
主な違い
gRPC 9: The operation was rejected because the system is not in a state required for the operation's execution. For example, deleting a non-empty directory.
gRPC 16: The request does not have valid authentication credentials for the operation.
You encounter 9 when the request is valid on its own, but the system's current state doesn't allow it — like trying to delete a non-empty directory or update a resource that has been modified concurrently.
You encounter 16 when no credentials were provided, or the provided token/certificate is expired or invalid. Different from PERMISSION_DENIED (code 7), which means authenticated but not authorized.
どちらをいつ使うか
For 9 (FAILED_PRECONDITION): Bring the system into the required state before retrying. For example, empty the directory first, or re-read the resource to get the latest version before updating. For 16 (UNAUTHENTICATED): Provide valid authentication credentials (e.g., refresh the OAuth token, regenerate the API key, or renew the client certificate).