Previously we believe it was necessary for all code that required ports
to use freeport to prevent conflicts.
https://github.com/dnephin/freeport-test shows that it is actually save
to use port 0 (`127.0.0.1:0`) as long as it is passed directly to
`net.Listen`, and the listener holds the port for as long as it is
needed.
This works because freeport explicitly avoids the ephemeral port range,
and port 0 always uses that range. As you can see from the test output
of https://github.com/dnephin/freeport-test, the two systems never use
overlapping ports.
This commit converts all uses of freeport that were being passed
directly to a net.Listen to use port 0 instead. This allows us to remove
a bit of wrapping we had around httptest, in a couple places.
This is a collection of refactors that make upcoming PRs easier to digest.
The main change is the introduction of the authmethod.Identity struct.
In the one and only current auth method (type=kubernetes) all of the
trusted identity attributes are both selectable and projectable, so they
were just passed around as a map[string]string.
When namespaces were added, this was slightly changed so that the
enterprise metadata can also come back from the login operation, so
login now returned two fields.
Now with some upcoming auth methods it won't be true that all identity
attributes will be both selectable and projectable, so rather than
update the login function to return 3 pieces of data it seemed worth it
to wrap those fields up and give them a proper name.
We set RawToString=true so that []uint8 => string when decoding an interface{}.
We set the MapType so that map[interface{}]interface{} decodes to map[string]interface{}.
Add tests to ensure that this doesn't break existing usages.
Fixes#7223
