feat: Add check_ping

Signed-off-by: Julien Riou <julien@riou.xyz>

lib/__init__.py

@@ -1,6 +1,30 @@
 import logging
 import os
 
+from nagiosplugin import Context
+from nagiosplugin.state import Critical, Ok, Unknown, Warn
+
+
+class BooleanContext(Context):
+    def __init__(self, name, expected=True, warning=False, critical=False):
+        super().__init__(name)
+        self.expected = expected
+        self.warning = warning
+        self.critical = critical
+
+    def evaluate(self, metric, resource):
+        if not metric.value is self.expected:
+            result_type = Ok
+            if self.critical:
+                result_type = Critical
+            elif self.warning:
+                result_type = Warn
+            return self.result_cls(
+                result_type, f"{metric.name} is not {self.expected}", metric
+            )
+        else:
+            return self.result_cls(Ok, None, metric)
+
 
 def show_version():
     with open(