A resource list formatter for graphviz dot diagrams

This change registers a "dot" formatter for the stack resource list
command. It generates the text for a graphviz dot diagram which can be
rendered as an image with this example usage:

  openstack stack resource list --format dot -n3 my_stack | dot -Tsvg -o my_stack.svg

Nested resources are fully supported by creating nodes for top-level
resources then linking stack resources to a subgraph representing the
nested stack.

Change-Id: I4b899287eaf818137d60cb278db2d86598aa6794

1 files changed, 150 insertions, 0 deletions

diff --git a/heatclient/common/resource_formatter.py b/heatclient/common/resource_formatter.py
new file mode 100644
index 0000000..7a5ec7f
--- /dev/null
+++ b/heatclient/common/resource_formatter.py
@@ -0,0 +1,150 @@
+#   Licensed under the Apache License, Version 2.0 (the "License"); you may
+#   not use this file except in compliance with the License. You may obtain
+#   a copy of the License at
+#
+#        http://www.apache.org/licenses/LICENSE-2.0
+#
+#   Unless required by applicable law or agreed to in writing, software
+#   distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#   WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#   License for the specific language governing permissions and limitations
+#   under the License.
+#
+
+import collections
+import hashlib
+
+from cliff.formatters import base
+
+
+class ResourceDotInfo(object):
+
+    def __init__(self, res):
+        self.resource = res
+        links = {l['rel']: l['href'] for l in res.links}
+        self.nested_dot_id = self.dot_id(links.get('nested'), 'stack')
+        self.stack_dot_id = self.dot_id(links.get('stack'), 'stack')
+        self.res_dot_id = self.dot_id(links.get('self'))
+
+    @staticmethod
+    def dot_id(url, prefix=None):
+        """Build an id with a prefix and a truncated hash of the URL"""
+        if not url:
+            return None
+        if not prefix:
+            prefix = 'r'
+        hash_object = hashlib.sha256(url.encode('utf-8'))
+        return '%s_%s' % (prefix, hash_object.hexdigest()[:20])
+
+
+class ResourceDotFormatter(base.ListFormatter):
+    def add_argument_group(self, parser):
+        pass
+
+    def emit_list(self, column_names, data, stdout, parsed_args):
+        writer = ResourceDotWriter(data, stdout)
+        writer.write()
+
+
+class ResourceDotWriter(object):
+
+    def __init__(self, data, stdout):
+        self.resources_by_stack = collections.defaultdict(
+            collections.OrderedDict)
+        self.resources_by_dot_id = collections.OrderedDict()
+        self.nested_stack_ids = []
+        self.stdout = stdout
+
+        for r in data:
+            rinfo = ResourceDotInfo(r)
+            if rinfo.stack_dot_id:
+                self.resources_by_stack[
+                    rinfo.stack_dot_id][r.resource_name] = rinfo
+            if rinfo.res_dot_id:
+                self.resources_by_dot_id[rinfo.res_dot_id] = rinfo
+            if rinfo.nested_dot_id:
+                self.nested_stack_ids.append(rinfo.nested_dot_id)
+
+    def write(self):
+        stdout = self.stdout
+
+        stdout.write('digraph G {\n')
+        stdout.write('  graph [\n'
+                     '    fontsize=10 fontname="Verdana" '
+                     'compound=true rankdir=LR\n'
+                     '  ]\n')
+
+        self.write_root_nodes()
+        self.write_subgraphs()
+        self.write_nested_stack_edges()
+        self.write_required_by_edges()
+        stdout.write('}\n')
+
+    def write_root_nodes(self):
+        for stack_dot_id in set(self.resources_by_stack.keys()).difference(
+                self.nested_stack_ids):
+            resources = self.resources_by_stack[stack_dot_id]
+            self.write_nodes(resources, 2)
+
+    def write_subgraphs(self):
+        for dot_id, rinfo in self.resources_by_dot_id.items():
+            if rinfo.nested_dot_id:
+                resources = self.resources_by_stack[rinfo.nested_dot_id]
+                if resources:
+                    self.write_subgraph(resources, rinfo)
+
+    def write_nodes(self, resources, indent):
+        stdout = self.stdout
+        spaces = ' ' * indent
+        for rinfo in resources.values():
+            r = rinfo.resource
+            dot_id = rinfo.res_dot_id
+            if r.resource_status.endswith('FAILED'):
+                style = 'style=filled color=red'
+            else:
+                style = ''
+            stdout.write('%s%s [label="%s\n%s" %s];\n'
+                         % (spaces, dot_id, r.resource_name,
+                            r.resource_type, style))
+        stdout.write('\n')
+
+    def write_subgraph(self, resources, nested_resource):
+        stdout = self.stdout
+        stack_dot_id = nested_resource.nested_dot_id
+        nested_name = nested_resource.resource.resource_name
+        stdout.write('  subgraph cluster_%s {\n' % stack_dot_id)
+        stdout.write('    label="%s";\n' % nested_name)
+        self.write_nodes(resources, 4)
+        stdout.write('  }\n\n')
+
+    def write_required_by_edges(self):
+        stdout = self.stdout
+        for dot_id, rinfo in self.resources_by_dot_id.items():
+            r = rinfo.resource
+
+            required_by = r.required_by
+            stack_dot_id = rinfo.stack_dot_id
+            if not required_by or not stack_dot_id:
+                continue
+
+            stack_resources = self.resources_by_stack.get(stack_dot_id, {})
+            for req in required_by:
+                other_rinfo = stack_resources.get(req)
+                if other_rinfo:
+                    stdout.write('  %s -> %s;\n'
+                                 % (rinfo.res_dot_id, other_rinfo.res_dot_id))
+        stdout.write('\n')
+
+    def write_nested_stack_edges(self):
+        stdout = self.stdout
+        for dot_id, rinfo in self.resources_by_dot_id.items():
+            if rinfo.nested_dot_id:
+                nested_resources = self.resources_by_stack[rinfo.nested_dot_id]
+                if nested_resources:
+                    first_resource = list(nested_resources.values())[0]
+                    stdout.write(
+                        '  %s -> %s [\n    color=dimgray lhead=cluster_%s '
+                        'arrowhead=none\n  ];\n'
+                        % (dot_id, first_resource.res_dot_id,
+                           rinfo.nested_dot_id))
+        stdout.write('\n')