contrib: add helper to graph current configuration

contrib/README.rst

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+labgrid-webapp
+==============
+
+labgrid-webapp implements a browser interface to access some of labgrid's
+information.
+
+Quick Start
+-----------
+
+.. code-block:: bash
+
+   $ cd labgrid/
+   $ source venv/bin/activate
+   venv $ pip install -r contrib/requirements-webapp.txt
+   venv $ ./contrib/labgrid-webapp --help
+   usage: labgrid-webapp [-h] [--crossbar URL] [--port PORT] [--proxy PROXY]
+
+   Labgrid webapp
+
+   options:
+     -h, --help            show this help message and exit
+     --crossbar URL, -x URL
+                           Crossbar websocket URL (default: ws://127.0.0.1:20408/ws)
+     --port PORT           Port to serve on
+     --proxy PROXY, -P PROXY
+
+   venv $ ./contrib/labgrid-webapp --help
+   INFO:     Available routes:
+   INFO:       - /labgrid/graph
+   INFO:     Started server process [2378028]
+   INFO:     Waiting for application startup.
+   INFO:     Application startup complete.
+   INFO:     Uvicorn running on http://0.0.0.0:8800 (Press CTRL+C to quit)
+   ...
+
+Please note that the graph feature relies on a valid `graphviz` system
+installation.
+
+By default the application will start on port 8800.
+
+See http://0.0.0.0:8800/docs for more information on available endpoints.

contrib/labgrid-webapp

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+#!/usr/bin/env python3
+import argparse
+import logging
+import os
+import sys
+from typing import Dict
+
+import graphviz
+import uvicorn
+from fastapi import FastAPI
+from fastapi.responses import Response
+
+from labgrid.remote.client import ClientSession, start_session
+from labgrid.remote.common import Place
+from labgrid.resource import Resource
+from labgrid.util.proxy import proxymanager
+
+
+async def do_graph(session: ClientSession) -> bytes:
+    '''Generate a graphviz graph of the current configuration.
+
+    Graph displays:
+    - all resources, grouped by groupname and exporter.
+    - all places, with a list of tags
+    - solid edges between places and acquired resources
+    - dotted edges between places and unacquired resources
+    - edges between resources and places carry the match name if any.
+    '''
+    def res_node_attr(name: str, resource: Resource) -> Dict[str, str]:
+        return {
+            'shape': 'plaintext',
+            'label': f'''<
+            <table bgcolor="peru">
+                <tr>
+                    <td border="0" align="left">Resource</td>
+                </tr>
+                <tr>
+                    <td port="cls">{resource.cls}</td>
+                    <td port="name" bgcolor="white">{name}</td>
+                </tr>
+            </table>>''',
+        }
+
+    def place_node_attr(name: str, place: Place) -> Dict[str, str]:
+        acquired = ''
+        bgcolor = 'lightblue'
+        if place.acquired:
+            bgcolor = 'cornflowerblue'
+            acquired = f'<td port="user" border="0" align="right"><b>{place.acquired}</b></td>'
+
+        tags = '<tr><td border="0" align="left">Tags</td></tr>' if place.tags else ''
+        for k, v in place.tags.items():
+            tags += f'<tr><td border="0"></td><td border="0" align="left">{k}={v}</td></tr>'
+
+        return {
+            'shape': 'plaintext',
+            'label': f'''<
+            <table bgcolor="{bgcolor}">
+                <tr>
+                    <td border="0" align="left">Place</td>
+                    {acquired}
+                </tr>
+                <tr>
+                    <td port="name" colspan="2" bgcolor="white">{name}</td>
+                </tr>
+                {tags}
+            </table>>''',
+        }
+
+    g = graphviz.Digraph('G')
+    g.attr(rankdir='LR')
+
+    paths = {}
+    for exporter, groups in session.resources.items():
+        g_exporter = graphviz.Digraph(f'cluster_{exporter}')
+        g_exporter.attr(label=exporter)
+
+        for group, resources in groups.items():
+            g_group = graphviz.Digraph(f'cluster_{group}')
+            g_group.attr(label=group)
+
+            for r_name, entry in resources.items():
+                res_node = f'{exporter}/{group}/{entry.cls}/{r_name}'.replace(':', '_')
+                paths[res_node] = [exporter, group, entry.cls, r_name]
+                g_group.node(res_node, **res_node_attr(r_name, entry))
+
+            g_exporter.subgraph(g_group)
+
+        g.subgraph(g_exporter)
+
+    for p_node, place in session.places.items():
+        g.node(p_node, **place_node_attr(p_node, place))
+
+        for m in place.matches:
+            for node, p in paths.items():
+                if m.ismatch(p):
+                    g.edge(
+                        f'{node}:name', p_node,
+                        style='solid' if place.acquired else 'dotted',
+                        label=m.rename if m.rename else None,
+                    )
+
+    return g.pipe(format='svg')
+
+
+def main():
+    app = FastAPI()
+    logger = logging.getLogger('uvicorn')
+
+    @app.get('/labgrid/graph')
+    async def get_graph() -> str:
+        '''Show a graph of the current infrastructure.'''
+        svg = await do_graph(session)
+        return Response(content=svg, media_type='image/svg+xml')
+
+    parser = argparse.ArgumentParser(
+        description='Labgrid webapp',
+        formatter_class=argparse.RawDescriptionHelpFormatter,
+    )
+    parser.add_argument(
+        '--crossbar',
+        '-x',
+        metavar='URL',
+        default=os.environ.get('LG_CROSSBAR', 'ws://127.0.0.1:20408/ws'),
+        help='Crossbar websocket URL (default: %(default)s)',
+    )
+    parser.add_argument('--port', type=int, default=8800, help='Port to serve on')
+    parser.add_argument('--proxy', '-P', help='Proxy connections via given ssh host')
+
+    args = parser.parse_args()
+
+    if args.proxy:
+        proxymanager.force_proxy(args.proxy)
+
+    try:
+        session = start_session(
+            args.crossbar, os.environ.get('LG_CROSSBAR_REALM', 'realm1'), {},
+        )
+    except ConnectionRefusedError:
+        logger.fatal('Unable to connect to labgrid crossbar')
+        return
+
+    server = uvicorn.Server(config=uvicorn.Config(
+        loop=session.loop,
+        host='0.0.0.0',
+        port=args.port,
+        app=app,
+    ))
+
+    logger.info('Available routes:')
+    for route in app.routes:
+        reserved_routes = ['/openapi.json', '/docs', '/docs/oauth2-redirect', '/redoc']
+        if route.path not in reserved_routes:
+            logger.info(f'  - {route.path}')
+
+    session.loop.run_until_complete(server.serve())
+
+
+if __name__ == '__main__':
+    sys.exit(main())

contrib/requirements-webapp.txt

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+fastapi
+graphviz
+uvicorn