Add SSH checks.

functions.tf

@@ -13,6 +13,7 @@ locals {
     "kodi",
     "transmission",
     "vouch",
+    "ssh",
   ]
   function_names = [for name in local.functions : "${local.function_name_prefix}-${replace(name, "_", "")}"]
 }

src/ssh.py

+from utils import check_ssh, publish
+
+
+def handler(event, context):  # pylint: disable=unused-argument
+    """Lambda event handler."""
+    for host in ["ns1.shore.co.il", "ns4.shore.co.il"]:
+        if check_ssh(host):
+            print(f"SSH on {host} is OK.")
+        else:
+            message = f"SSH on {host} failed."
+            print(message)
+            publish(message)
+
+
+if __name__ == "__main__":
+    handler("event", "context")

src/utils.py

 # pylint: disable=import-error
 import os
+import socket
 import boto3
 import requests
 
@@ -36,3 +37,15 @@ def check_urls(checks):
             message = f"Failed check for {check['url']}."
             print(message)
             publish(message)
+
+
+def check_ssh(host, port=22):
+    """Check that an SSH server is available on that host and port."""
+    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+    try:
+        sock.connect((host, port))
+        msg = sock.recv(1024)
+        return msg.startswith(b"SSH-2.0-OpenSSH")
+    except Exception as e:  # pylint: disable=broad-except,invalid-name
+        print(str(e))
+        return False