This makes the metrics package more extensible by allowing the default name of
`container_id` to be changed by the package caller.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
* only shim v2 runc v2 ("io.containerd.runc.v2") is supported
* only PID metrics is implemented. Others should be implemented in separate PRs.
* lots of code duplication in v1 metrics and v2 metrics. Dedupe should be separate PR.
Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>
