Add support for I2PD application monitoring (#586)

* SNMP extend agent for application I2Pd

* Better error reporting to LibreNMS. Minor tweaks

* Update i2pd-stats.py

* Fixed code layout as Super-Linter suggested

---------

Co-authored-by: Neil Lathwood <[email protected]>

Author: kossusukka

snmp/i2pd-stats.py

@@ -0,0 +1,114 @@
+#!/usr/bin/env python3
+
+# i2pd-stats.py
+#   SNMP Extend-agent for exporting I2Pd statistics to LibreNMS
+#
+#   Inspired from i2pdctl:
+#       https://github.com/PurpleI2P/i2pd-tools
+#
+#   Run script and it will print JSON-blob into stdout
+#   Set I2P Control socket params below!
+#
+#   Installation:
+#       1. copy this file to /etc/snmp/i2pd-stats.py
+#       2. chmod +x /etc/snmp/i2pd-stats.py
+#       3. edit /etc/snmp/snmpd.conf and add following line:
+#           extend i2pd /etc/snmp/i2pd-stats.py
+#       4. systemctl restart snmpd.service
+#
+#   author: Kossusukka <[email protected]>
+
+import json
+import os
+import ssl
+import urllib.error
+import urllib.parse
+import urllib.request
+
+######### CONFIGURATION ##############
+I2PC_URL = "https://127.0.0.1:7650/"
+I2PC_PASS = "itoopie"
+##### END OF CONFIGURATION ###########
+
+
+# Do not change! Must match LibreNMS version
+JSONVER = "1"
+
+
+class I2PControl(object):
+    """Talk to I2PControl API"""
+
+    def __init__(self, url, password):
+        self.url = url
+        self.password = password
+        self._token = None
+
+    @property
+    def token(self):
+        """Cached authentication token"""
+        if not self._token:
+            try:
+                self._token = self.do_post(
+                    self.url,
+                    json.dumps(
+                        {
+                            "id": 1,
+                            "method": "Authenticate",
+                            "params": {"API": 1, "Password": self.password},
+                            "jsonrpc": "2.0",
+                        }
+                    ),
+                )["result"]["Token"]
+            except KeyError:
+                post_error("1", "Invalid I2PControl password or token!")
+                exit(1)
+        return self._token
+
+    def do_post(self, url, data):
+        """HTTP(S) handler"""
+        req = urllib.request.Request(url, data=data.encode())
+        try:
+            with urllib.request.urlopen(
+                req, context=ssl._create_unverified_context(), timeout=5
+            ) as f:
+                resp = f.read().decode("utf-8")
+        except urllib.error.URLError:
+            post_error("2", "Unable to connect I2PControl socket!")
+            exit(1)
+        except TimeoutError:
+            post_error("3", "Connection timed out to I2PControl socket!")
+            exit(1)
+        return json.loads(resp)
+
+    def request(self, method, params):
+        """Execute authenticated request"""
+        params["Token"] = self.token
+        return self.do_post(
+            self.url,
+            json.dumps({"id": 1, "method": method, "params": params, "jsonrpc": "2.0"}),
+        )
+
+
+def post_error(code: str, message: str):
+    """Post error code+message as JSON for LibreNMS"""
+    resp_err = {"data": "", "version": JSONVER, "error": code, "errorString": message}
+
+    print(json.dumps(resp_err))
+
+
+def main():
+    # Craft JSON request for I2PC
+    JSON_REQUEST = json.loads(
+        '{ "i2p.router.uptime": "", "i2p.router.net.status": "", "i2p.router.net.bw.inbound.1s": "", "i2p.router.net.bw.inbound.15s": "", "i2p.router.net.bw.outbound.1s": "", "i2p.router.net.bw.outbound.15s": "", "i2p.router.net.tunnels.participating": "", "i2p.router.net.tunnels.successrate": "", "i2p.router.netdb.knownpeers": "", "i2p.router.netdb.activepeers": "", "i2p.router.net.total.received.bytes": "", "i2p.router.net.total.sent.bytes": "" }'
+    )
+
+    ctl = I2PControl(I2PC_URL, I2PC_PASS)
+
+    resp = ctl.request("RouterInfo", JSON_REQUEST)["result"]
+    resp_full = {"data": resp, "version": JSONVER, "error": "0", "errorString": ""}
+
+    print(json.dumps(resp_full))
+
+
+if __name__ == "__main__":
+    main()