[ovs-dev] [RFC 06/11] python: add flow base class

Adrian Moreno amorenoz at redhat.com
Wed Sep 1 10:00:58 UTC 2021


It simplifies the implementation of different types of flows by creating
the concept of Section (e.g: match, action) and automatic accessors for
all the provided Sections

Signed-off-by: Adrian Moreno <amorenoz at redhat.com>
---
 python/automake.mk       |  3 +-
 python/ovs/flows/flow.py | 81 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 83 insertions(+), 1 deletion(-)
 create mode 100644 python/ovs/flows/flow.py

diff --git a/python/automake.mk b/python/automake.mk
index 9dfc62fce..136da26bd 100644
--- a/python/automake.mk
+++ b/python/automake.mk
@@ -45,7 +45,8 @@ ovs_pyfiles = \
 	python/ovs/flows/__init__.py \
 	python/ovs/flows/decoders.py \
 	python/ovs/flows/kv.py \
-	python/ovs/flows/list.py
+	python/ovs/flows/list.py \
+	python/ovs/flows/flow.py
 
 # These python files are used at build time but not runtime,
 # so they are not installed.
diff --git a/python/ovs/flows/flow.py b/python/ovs/flows/flow.py
new file mode 100644
index 000000000..e1673bba8
--- /dev/null
+++ b/python/ovs/flows/flow.py
@@ -0,0 +1,81 @@
+""" Defines the Flow class
+"""
+
+from ovs.flows.kv import KeyValue
+
+
+class Section(object):
+    """A section within a Flow
+
+    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
+            (e.g: 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):
+        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)
+
+    For each section provided, the object will have the following attributes
+    {section} will return the sections data in a formatted way
+    {section}_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
+    """
+
+    def __init__(self, sections, orig=""):
+        self._sections = sections
+        self._orig = orig
+        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 sections(self):
+        """Return the section by name"""
+        return self._sections
+
+    @property
+    def orig(self):
+        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
-- 
2.31.1



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