Scrape OpenVPN metrics from OpenVPN management interface

exporter.py

@@ -1,6 +1,8 @@
 #!/usr/bin/env python
 
+import asyncio
 import os
+from collections import Counter
 from motor.motor_asyncio import AsyncIOMotorClient
 from sanic import Sanic, response
 
@@ -8,19 +10,71 @@ app = Sanic("exporter")
 
 MONGO_URI = os.getenv("MONGO_URI", "mongodb://127.0.0.1:27017/default")
 
-@app.listener('before_server_start')
+
+@app.listener("before_server_start")
 async def setup_db(app, loop):
     app.ctx.db = AsyncIOMotorClient(MONGO_URI).get_default_database()
 
+
+async def wrap(i, prefix="pinecrypt_gateway_"):
+    metrics_seen = set()
+    async for name, tp, value, labels in i:
+        if name not in metrics_seen:
+            yield "# TYPE %s %s" % (name, tp)
+            metrics_seen.add(name)
+        yield "%s%s %d" % (
+            prefix + name,
+            ("{%s}" % ",".join(["%s=\"%s\"" % j for j in labels.items()]) if labels else ""),
+            value)
+
+
+async def exporter_stats():
+    # Export number of open file handles
+    yield "exporter_file_descriptors", "gauge", len(os.listdir("/proc/self/fd")), {}
+
+
+async def openvpn_stats(port, service):
+    last_seen = Counter()
+
+    # Export OpenVPN status
+    reader, writer = await asyncio.open_connection("127.0.0.1", port)
+    writer.write(b"status 2\n")
+    await writer.drain()
+    while True:
+        line = await reader.readline()
+        values = line.decode("ascii").strip().split(",")
+        header = values[0]
+
+        if header == "END":
+            break
+        elif header == "CLIENT_LIST":
+            _, cn, remote, _, _, rxbytes, txbytes, _, since, _, cid, pid, cipher = values
+            labels = {"cn": cn, "service": service}
+            yield "client_connected_since", "gauge", int(since), labels
+
+            labels["cipher"] = cipher
+            yield "client_rx_bytes", "counter", int(rxbytes), labels
+            yield "client_tx_bytes", "counter", int(txbytes), labels
+        elif header == "ROUTING_TABLE":
+            _, addr, cn, remote, _, last_ref = values
+            last_seen[cn] = max(last_seen[cn], int(last_ref))
+
+    writer.close()
+    await writer.wait_closed()
+
+    for key, value in last_seen.items():
+        yield "client_last_seen", "gauge", value, {"cn": key, "service": service}
+
+
 @app.route("/metrics")
 async def view_export(request):
     coll = app.ctx.db["certidude_certificates"]
+
     async def streaming_fn(response):
-        await response.write("# HELP pinecrypt_remote_last_seen Remote client last seen\n")
-        await response.write("# TYPE pinecrypt_remote_last_seen gauge\n")
-        async for doc in coll.find({"status":"signed", "last_seen":{"$exists":True}}, {"common_name":1, "last_seen":1}):
-            await response.write("pinecrypt_remote_last_seen{cn=\"%s\"} %d\n" % (
-                doc["common_name"], doc["last_seen"].timestamp()))
-    return response.stream(streaming_fn, content_type='text/plain')
+        for i in exporter_stats(), openvpn_stats(7505, "openvpn-udp"), openvpn_stats(7506, "openvpn-tcp"):
+            async for line in wrap(i):
+                await response.write(line + "\n")
+
+    return response.stream(streaming_fn, content_type="text/plain")
 
 app.run(port=3001)