Move k8s resource string parsing to a utility method

[terrytangyuan]

See below. This should be removed to a utility method that can be reused across different steps.

couler/couler/steps/tensorflow.py

Lines 71 to 91 in 57e6c0b

	if resources is not None:
	# User-defined resource, should be formatted like
	# "cpu=1,memory=1024,disk=2048,gpu=1,gpu_type=p100,shared_memory=20480"
	try:
	kvs = resources.split(",")
	print(kvs)
	limits = {}
	for kv in kvs:
	k, v = kv.split("=")
	if k in ["gpu", "memory", "disk", "shared_memory"]:
	v = int(v)
	elif k == "cpu":
	v = float(v)
	limits[k] = v
	resource_limits = {"limits": limits}
	container["resources"] = resource_limits
	except Exception:
	raise Exception("Unrecognized resource type %s" % resources)

[terrytangyuan]

Actually the resources in APIs like couler.run_container() are specified as a dictionary instead of a string currently. For pre-defined Couler steps, should we be consistent? A string that represents the resources does not seem necessary since we are not building a CLI here and Python dictionary would be more intuitive to users. What do you think? @merlintang @ywskycn