Previously, the log lines appeared in stdout before the JSON encoding of
the error message. That would break JSON parsing of stdout. Instead, we use
stderr for these unstructured logs, consistent with the CNI spec.
This takes some of the machinery from CNI and from the rkt networking
code, and turns it into a library that can be linked into go apps.
Included is an example command-line application that uses the library,
called `cnitool`.
Other headline changes:
* Plugin exec'ing is factored out
The motivation here is to factor out the protocol for invoking
plugins. To that end, a generalisation of the code from api.go and
pkg/plugin/ipam.go goes into pkg/invoke/exec.go.
* Move argument-handling and conf-loading into public API
The fact that the arguments get turned into an environment for the
plugin is incidental to the API; so, provide a way of supplying them
as a struct or saying "just use the same arguments as I got" (the
latter is for IPAM plugins).
When plugin errors out, it prints out a JSON object to stdout
describing the failure. This object needs to be propagated out
through the plugins and to the container runtime. This change
also adds Print method to both the result and error structs
for easy serialization to stdout.
This adds basic plugins.
"main" types: veth, bridge, macvlan
"ipam" type: host-local
The code has been ported over from github.com/coreos/rkt project
and adapted to fit the CNI spec.
