Changes based on Leo's review including cleaner code, better error ha…

…ndling

checks.d/sftp_check.py

@@ -0,0 +1,83 @@
+# stdlib
+import time
+import socket
+# 3p
+import paramiko
+# project
+from checks import AgentCheck
+
+class CheckSSH(AgentCheck):
+
+    def _load_conf(self, instance):
+        if 'host' not in instance or not instance['host']:
+            raise Exception ("No host has been specified")  #maybe use dict instead
+        else:
+            host = instance['host']
+
+        if 'port' not in instance:
+            self.log.info("No port specified, defaulted to 22")
+            port = 22
+        else:
+            port = int(instance['port'])
+
+        if 'username' not in instance or not instance['username']:
+            raise Exception ("No username has been specified")
+        else:
+            username = instance['username']
+
+        if 'password' not in instance or not instance['password']:
+            self.log.info("No password specified")
+            password = None
+        else:
+            password = instance['password']
+
+        if 'private_key' not in instance or not instance['private_key']:
+            self.log.info("No private_key specified")
+            private_key = None
+        else:
+            private_key = instance['private_key']
+
+        return host, port, username, password, private_key
+
+    def check(self, instance):
+        host, port, username, password, private_key = self._load_conf(instance)
+
+        client = paramiko.SSHClient()
+        client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
+        client.load_system_host_keys()
+
+        try:
+            exception_message = 'No errors'
+            client.connect(host, port=port, username=username, password=password, pkey=private_key)
+
+        except Exception as e:
+            exception_message = "{0}".format(e)
+
+        #Service Availability to see if up or down
+        if exception_message == 'No errors':
+            try:
+                sftp = client.open_sftp()
+            except Exception as e:
+                exception_message = "{0}".format(e)
+                status = AgentCheck.CRITICAL
+
+            start_time = time.time()
+
+            try:
+                result = sftp.listdir('.')
+            except Exception as e:
+                exception_message = "{0}".format(e)
+                status = AgentCheck.CRITICAL
+
+            if result is not None:
+                status = AgentCheck.OK
+                end_time = time.time()
+                time_taken = end_time - start_time
+                self.gauge('ssh.response_time', time_taken)
+            else:
+                status = AgentCheck.CRITICAL
+                exception_message = 'An error has occured'
+        else:
+            status = AgentCheck.CRITICAL
+
+        self.service_check('sftp.can_connect', status, message=exception_message)

conf.d/sftp_check.yaml.example

@@ -0,0 +1,9 @@
+init_config:
+
+instances:
+    - host: localhost
+#port defaults to 22 if not specified
+      port: 22
+      username: test
+      password: abcd
+      private_key: