dk.sdu.cloud.file.orchestrator.api.UFile

UCloud Developer Guide / Orchestration of Resources / Storage / Files

UFile

A UFile is a resource for storing, retrieving and organizing data in UCloud

data class UFile(
    val id: String,
    val specification: UFileSpecification,
    val createdAt: Long,
    val status: UFileStatus,
    val owner: ResourceOwner,
    val permissions: ResourcePermissions?,
    val updates: List<UFileUpdate>,
    val providerGeneratedId: String?,
)

A file in UCloud (UFile) closely follows the concept of a computer file you might already be familiar with. The functionality of a file is mostly determined by its type. The two most important types are the DIRECTORY and FILE types. A DIRECTORY is a container of UFiles. A directory can itself contain more directories, which leads to a natural tree-like structure. FILEs, also referred to as a regular files, are data records which each contain a series of bytes.

All files in UCloud have a name associated with them. This name uniquely identifies them within their directory. All files in UCloud belong to exactly one directory.

File operations must be able to reference the files on which they operate. In UCloud, these references are made through the id property, also known as a path. Paths use the tree-like structure of files to reference a file, it does so by declaring which directories to go through, starting at the top, to reach the file we are referencing. This information is serialized as a textual string, where each step of the path is separated by forward-slash / (U+002F). The path must start with a single forward-slash, which signifies the root of the file tree. UCloud never users 'relative' file paths, which some systems use.

All files in UCloud additionally have metadata associated with them. For this we differentiate between system-level metadata and user-defined metadata.

We have just covered two examples of system-level metadata, the id (path) and type. UCloud additionally supports metadata such as general stats about the files, such as file sizes. All files have a set of permissions associated with them, providers may optionally expose this information to UCloud and the users.

User-defined metadata describe the contents of a file. All metadata is described by a template (FileMetadataTemplate), this template defines a document structure for the metadata. User-defined metadata can be used for a variety of purposes, such as: Datacite metadata, sensitivity levels, and other field specific metadata formats.

Properties