Status is exposed as v1 in the current schema (so all groups are
returning v1.Status). However, if you give a codec only "mygroup"
"myversion", it will fail to convert Status to v1. For now, unversioned
types should be allowed to be projected into all group versions, and
when we add the server group we'll rip out the unversioned concept
entirely.
Convert single GV and lists of GVs into an interface that can handle
more complex scenarios (everything internal, nothing supported). Pass
the interface down into conversion.
We will probably readd these as an opaque object passed down to
conversions that lets the caller get access to more info (like
a negotiated serializer).
reflect.Call is fairly expensive, performing 8 allocations and having to
set up a call stack. Using a fairly straightforward to generate switch
statement, we can bypass that early in conversion (as long as the
function takes responsibility for invocation). We may also be able to
avoid an allocation for the conversion scope, but not positive yet.
```
benchmark old ns/op new ns/op delta
BenchmarkPodConversion-8 14713 12173 -17.26%
benchmark old allocs new allocs delta
BenchmarkPodConversion-8 80 72 -10.00%
benchmark old bytes new bytes delta
BenchmarkPodConversion-8 9133 8712 -4.61%
```
Break Codec into two general purpose interfaces, Encoder and Decoder,
and move parameter codec responsibilities to ParameterCodec.
Make unversioned types explicit when registering - these types go
through conversion without modification.
Switch to use "__internal" instead of "" to represent the internal
version. Future commits will also add group defaulting (so that "" is
expanded internally into a known group version, and only cleared during
set).
For embedded types like runtime.Object -> runtime.RawExtension, put the
responsibility on the caller of Decode/Encode to handle transformation
into destination serialization. Future commits will expand RawExtension
and Unknown to accept a content encoding as well as bytes.
Make Unknown a bit more powerful and use it to carry unrecognized types.
The pending codec -> conversion split changes the signature of
Encode and Decode to be more complicated. Create a stub helper
with the exact semantics of today and do the simple mechanical
refactor here to reduce the cost of that change.
Make clients opt in to decoding objects that are stored
in the generic api.List object by invoking runtime.DecodeList()
with a set of schemes. Makes it easier to handle unknown
schema objects because decoding is in the control of the code.
Add runtime.Unstructured, which is a simple in memory
representation of an external object.
kubectl get can output a series of objects as a List in versioned
form, but not all API objects are available in the same schema.
Make the act of converting a []runtime.Object to api.List more
robust and add a test to verify its behavior in Get.
Makes it easier for client code to output unified objects.
Clayton Coleman