python: ovs: flowviz: Add datapath graph format.

Graph view leverages the TreeFlow hierarchy and uses graphviz library to
build a visual graph of the datapath tree.

Conntrack zones are shown in random colors to help visualize connection
tracking interdependencies.

An html flag builds an HTML page with both the html flows and the graph
(in svg) that enables navigation.

Examples:
$ ovs-appctl dpctl/dump-flows -m | ovs-flowviz datapath graph | dot
-Tpng -o graph.png
$ ovs-appctl dpctl/dump-flows -m | ovs-flowviz datapath graph --html >
flows.html

Acked-by: Eelco Chaudron <[email protected]>
Signed-off-by: Adrian Moreno <[email protected]>
Signed-off-by: Ilya Maximets <[email protected]>

python/automake.mk

@@ -71,6 +71,7 @@ ovs_flowviz = \
 	python/ovs/flowviz/main.py \
 	python/ovs/flowviz/odp/__init__.py \
 	python/ovs/flowviz/odp/cli.py \
+	python/ovs/flowviz/odp/graph.py \
 	python/ovs/flowviz/odp/html.py \
 	python/ovs/flowviz/odp/tree.py \
 	python/ovs/flowviz/ofp/__init__.py \

python/ovs/flowviz/odp/cli.py

@@ -15,6 +15,8 @@
 import click
 
 from ovs.flowviz.main import maincli
+
+from ovs.flowviz.odp.graph import GraphProcessor
 from ovs.flowviz.odp.html import HTMLTreeProcessor
 from ovs.flowviz.odp.tree import ConsoleTreeProcessor
 from ovs.flowviz.process import (
@@ -84,3 +86,24 @@ def html(opts):
     processor = HTMLTreeProcessor(opts)
     processor.process()
     processor.print()
+
+
+@datapath.command()
+@click.option(
+    "-h",
+    "--html",
+    is_flag=True,
+    default=False,
+    show_default=True,
+    help="Output an html file containing the graph",
+)
+@click.pass_obj
+def graph(opts, html):
+    """Print the flows in a graphviz (.dot) format showing the relationship
+    of recirc_ids."""
+    if len(opts.get("filename")) > 1:
+        raise click.BadParameter("Graph format only supports one input file")
+
+    processor = GraphProcessor(opts)
+    processor.process()
+    processor.print(html)