mediatype

Documentation

Index

• func IsRegisteredPackage(pkgPath string) bool
• func IsTarget(mediaType string) bool
• func RegisterParser(mediaType string, parser ParseFunc)
• func RegisterTarget(mediaType string)
• type ParseFunc
  • func CustomJSONParser(v interface{}) ParseFunc
  • func GetParser(mediaType string) ParseFunc

Functions

func IsRegisteredPackage

func IsRegisteredPackage(pkgPath string) bool

IsRegisteredPackage returns whether a parser which returns a type from the given package path was registered. This is only useful to allow restricting reflection recursion (as a first-pass to limit how deep reflection goes).

func IsTarget

func IsTarget(mediaType string) bool

IsTarget returns whether the given media-type should be treated as a "target media-type" for the purposes of reference resolution. This means that either the media-type has been registered as a target (using RegisterTarget) or has not been registered as parseable (using RegisterParser).

func RegisterParser

func RegisterParser(mediaType string, parser ParseFunc)

RegisterParser registers a new ParseFunc to be used when the given media-type is encountered during parsing or recursive walks of blobs. See the documentation of ParseFunc for more detail.

func RegisterTarget

func RegisterTarget(mediaType string)

RegisterTarget registers that a given *parseable* media-type (meaning that there is a parser already registered using RegisterParser) should be treated as a "target" for the purposes of reference resolution. This means that if this media-type is encountered during a reference resolution walk, a DescriptorPath to *that* blob will be returned and resolution will not recurse any deeper. All un-parseable blobs are treated as targets, so this is only useful for blobs that have also been given parsers.

Types

type ParseFunc

type ParseFunc func(io.Reader) (interface{}, error)

ParseFunc is a parser that is registered for a given mediatype and called to parse a blob if it is encountered. If possible, the blob should be represented as a native Go object (with all Descriptors represented as ispec.Descriptor objects) -- this will allow umoci to recursively discover blob dependencies.

Currently, we require the returned interface{} to be a raw struct (unexpected behaviour may occur otherwise).

NOTE: Your ParseFunc must be able to accept a nil Reader (the error

value is not relevant). This is used during registration in order to
determine the type of the struct (thus you must return a struct that
you would return in a non-nil reader scenario). Go doesn't have a way
for us to enforce this.

func CustomJSONParser

func CustomJSONParser(v interface{}) ParseFunc

CustomJSONParser creates a custom ParseFunc which JSON-decodes blob data into the type of the given value (which *must* be a struct, otherwise CustomJSONParser will panic). This is intended to make ergonomic use of RegisterParser much simpler.

func GetParser

func GetParser(mediaType string) ParseFunc

GetParser returns the ParseFunc that was previously registered for the given media-type with RegisterParser (or nil if the media-type is unknown).