Allow incrementing counters with a float

Signed-off-by: Lukas Kämmerling <lukas.kaemmerling@hetzner-cloud.de>

Author: LKaemmerling

src/Prometheus/Counter.php

@@ -27,10 +27,10 @@ public function inc(array $labels = []): void
     }
 
     /**
-     * @param int $count e.g. 2
+     * @param int|float $count e.g. 2
      * @param mixed[] $labels e.g. ['status', 'opcode']
      */
-    public function incBy(int $count, array $labels = []): void
+    public function incBy($count, array $labels = []): void
     {
         $this->assertLabelsAreDefinedCorrectly($labels);
 
@@ -42,7 +42,7 @@ public function incBy(int $count, array $labels = []): void
                 'labelNames' => $this->getLabelNames(),
                 'labelValues' => $labels,
                 'value' => $count,
-                'command' => Adapter::COMMAND_INCREMENT_INTEGER,
+                'command' => is_float($count) ? Adapter::COMMAND_INCREMENT_FLOAT : Adapter::COMMAND_INCREMENT_INTEGER,
             ]
         );
     }

tests/Test/Prometheus/AbstractCounterTest.php

@@ -127,6 +127,40 @@ public function itShouldIncreaseTheCounterByAnArbitraryInteger(): void
         );
     }
 
+    /**
+     * @test
+     */
+    public function itShouldIncreaseTheCounterWithAFloat(): void
+    {
+        $counter = new Counter($this->adapter, 'test', 'some_metric', 'this is for testing', ['foo', 'bar']);
+        $counter->inc(['lalal', 'lululu']);
+        $counter->incBy(1.5, ['lalal', 'lululu']);
+        self::assertThat(
+            $this->adapter->collect(),
+            self::equalTo(
+                [
+                    new MetricFamilySamples(
+                        [
+                            'type' => Counter::TYPE,
+                            'help' => 'this is for testing',
+                            'name' => 'test_some_metric',
+                            'labelNames' => ['foo', 'bar'],
+                            'samples' => [
+                                [
+                                    'labelValues' => ['lalal', 'lululu'],
+                                    'value' => 2.5,
+                                    'name' => 'test_some_metric',
+                                    'labelNames' => [],
+                                ],
+                            ],
+                        ]
+                    ),
+                ]
+            )
+        );
+    }
+
+
     /**
      * @test
      */