Viewing file:  flow.py (3.68 KB) -rw-r--r--
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""" Defines the Flow class.
"""
class Section(object):
"""A flow can be seen as composed of different sections, e.g:
[info] [match] actions=[actions]
This class represents each of those sections.
A section is basically a set of Key-Value pairs. Typically, they can be
expressed as a dictionary, for instance the "match" part of a flow can be
expressed as:
{
"nw_src": "192.168.1.1",
"nw_dst": "192.168.1.2",
}
However, some of them must be expressed as a list which allows for
duplicated keys. For instance, the "actions" section could be:
[
{
"output": 32
},
{
"output": 33
}
]
The is_list flag is used to discriminate this.
Attributes:
name (str): Name of the section.
pos (int): Position within the overall flow string.
string (str): Section string.
data (list[KeyValue]): Parsed data of the section.
is_list (bool): Whether the key-values shall be expressed as a list
(i.e: it allows repeated keys).
"""
def __init__(self, name, pos, string, data, is_list=False):
self.name = name
self.pos = pos
self.string = string
self.data = data
self.is_list = is_list
def __str__(self):
return "{} (at {}): {}".format(self.name, self.pos, self.string)
def __repr__(self):
return "%s('%s')" % (self.__class__.__name__, self)
def dict(self):
return {self.name: self.format_data()}
def format_data(self):
"""Returns the section's key-values formatted in a dictionary or list
depending on the value of is_list flag.
"""
if self.is_list:
return [{item.key: item.value} for item in self.data]
else:
return {item.key: item.value for item in self.data}
class Flow(object):
"""The Flow class is a base class for other types of concrete flows
(such as OFproto Flows or DPIF Flows).
A flow is basically comprised of a number of sections.
For each section named {section_name}, the flow object will have the
following attributes:
- {section_name} will return the sections data in a formatted way.
- {section_name}_kv will return the sections data as a list of KeyValues.
Args:
sections (list[Section]): List of sections that comprise the flow
orig (str): Original flow string.
id (Any): Optional; identifier that clients can use to uniquely
identify this flow.
"""
def __init__(self, sections, orig="", id=None):
self._sections = sections
self._orig = orig
self._id = id
for section in sections:
setattr(
self, section.name, self.section(section.name).format_data()
)
setattr(
self,
"{}_kv".format(section.name),
self.section(section.name).data,
)
def section(self, name):
"""Return the section by name."""
return next(
(sect for sect in self._sections if sect.name == name), None
)
@property
def id(self):
"""Return the Flow ID."""
return self._id
@property
def sections(self):
"""Return the all the sections in a list."""
return self._sections
@property
def orig(self):
"""Return the original flow string."""
return self._orig
def dict(self):
"""Returns the Flow information in a dictionary."""
flow_dict = {"orig": self.orig}
for section in self.sections:
flow_dict.update(section.dict())
return flow_dict
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