Metadata

MetadataKey provides a general interface using key and path to retrieve value from Metadata.

For example, for the following Metadata:

The following MetadataKey will retrieve a string value “bar” from the Metadata.

path:
- key: prop
- key: foo

{
  "key": "...",
}

key

(, REQUIRED) The key name of Metadata to retrieve the Struct from the metadata. Typically, it represents a builtin subsystem or custom extension.

path

(type.metadata.v3.MetadataKey.PathSegment, REQUIRED) The path to retrieve the Value from the Struct. It can be a prefix or a full path, e.g. [prop, xyz] for a struct or [prop, foo] for a string in the example, which depends on the particular scenario.

Note: Due to that only the key type segment is supported, the path can not specify a list unless the list is the last segment.

type.metadata.v3.MetadataKey.PathSegment

[type.metadata.v3.MetadataKey.PathSegment proto]

Specifies the segment in a path to retrieve value from Metadata. Currently it is only supported to specify the key, i.e. field name, as one segment of a path.

(, REQUIRED) If specified, use the key to retrieve the value in a Struct.

[type.metadata.v3.MetadataKind proto]

Describes what kind of metadata.

  "request": "{...}",
  "cluster": "{...}",
  "host": "{...}"
}

request

() Request kind of metadata.

Precisely one of request, , cluster, must be set.

route

(type.metadata.v3.MetadataKind.Route) Route kind of metadata.

Precisely one of , route, , host must be set.

cluster

Precisely one of , route, , host must be set.

host

() Host kind of metadata.

Precisely one of request, , cluster, must be set.

type.metadata.v3.MetadataKind.Request

Represents dynamic metadata associated with the request.

{}

[type.metadata.v3.MetadataKind.Route proto]

Represents metadata from .

type.metadata.v3.MetadataKind.Cluster

Represents metadata from the upstream cluster.

{}

Represents metadata from .