Eerste versie

utils/prometheus_additions.py

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+"""
+Additions and enhancements to the prometheus_client package
+"""
+
+import prometheus_client as prometheus
+
+class CounterAbsolute(prometheus.Counter):
+    """
+    CounterAbsolute allows to set the Counter by an absolute value like Gauge, but data is 
+    handled properly if counter resets or over flows.
+    CounterAbsolute is typically used if values need to by proxied from another source e.g. 
+    a network counter, SMTP or MQTT data which return increasing but absolute numbers 
+    instead of a diff.
+
+    As Counter must not decrease, setting CounterAbsolute to a lower value is handled as follows:
+    A counter overflow or a reset is assumed and the create timestamp gets reset and internally 
+    a new Value object created.
+
+    An example for a CounterAbsolute:
+        from prometheus_client import Counter
+        c = CounterAbsolute('my_failures_total', 'Description of counter')
+        c.set(1123.63213)  # Set to an absolute value. If lower than last value, Counter gets reset.
+
+    """
+    _type = 'counter'
+
+
+    def set(self, value, fail_on_decrease=False):
+        """Increment counter to the given amount."""
+        self._raise_if_not_observable()
+        if value < 0:
+            raise ValueError('Counters can be a positive number only.')
+        if value >= self._value.get():
+            self._value.set(float(value))
+        else:
+            if fail_on_decrease:
+                raise ValueError(f"Counter must increase {value} lower {self._value.get()}")
+            else:
+                self._metric_init()
+                self._value.set(float(value))