From 62be02a5ce7a60a54b672f48046c767a22d84f8d Mon Sep 17 00:00:00 2001
From: Rafael Dohms <rdohms@gmail.com>
Date: Fri, 17 Nov 2017 14:36:13 +0100
Subject: [PATCH] Extract Interfaces for User Interaction Classes

The registry and the rederer are classes that are usually injected by
users into their own code, having interfaces for them allow users to
mock based on the API and not on the concret implementation which avoids
a common code smell. This also allows better custom implementations if
users so desire.
---
 src/Prometheus/CollectorRegistry.php |   2 +-
 src/Prometheus/RegistryInterface.php | 106 +++++++++++++++++++++++++++
 src/Prometheus/RenderTextFormat.php  |   2 +-
 src/Prometheus/RendererInterface.php |  14 ++++
 4 files changed, 122 insertions(+), 2 deletions(-)
 create mode 100644 src/Prometheus/RegistryInterface.php
 create mode 100644 src/Prometheus/RendererInterface.php

diff --git a/src/Prometheus/CollectorRegistry.php b/src/Prometheus/CollectorRegistry.php
index 9ff18e3..23e0965 100644
--- a/src/Prometheus/CollectorRegistry.php
+++ b/src/Prometheus/CollectorRegistry.php
@@ -9,7 +9,7 @@
 use Prometheus\Storage\Adapter;
 use Prometheus\Storage\Redis;
 
-class CollectorRegistry
+class CollectorRegistry implements RegistryInterface
 {
     /**
      * @var CollectorRegistry
diff --git a/src/Prometheus/RegistryInterface.php b/src/Prometheus/RegistryInterface.php
new file mode 100644
index 0000000..7bae64d
--- /dev/null
+++ b/src/Prometheus/RegistryInterface.php
@@ -0,0 +1,106 @@
+<?php
+
+namespace Prometheus;
+
+use Prometheus\Exception\MetricNotFoundException;
+use Prometheus\Exception\MetricsRegistrationException;
+
+interface RegistryInterface
+{
+    /**
+     * @return MetricFamilySamples[]
+     */
+    public function getMetricFamilySamples();
+
+    /**
+     * @param string $namespace e.g. cms
+     * @param string $name e.g. duration_seconds
+     * @param string $help e.g. The duration something took in seconds.
+     * @param array  $labels e.g. ['controller', 'action']
+     *
+     * @return Gauge
+     * @throws MetricsRegistrationException
+     */
+    public function registerGauge($namespace, $name, $help, $labels = []);
+
+    /**
+     * @param string $namespace
+     * @param string $name
+     *
+     * @return Gauge
+     * @throws MetricNotFoundException
+     */
+    public function getGauge($namespace, $name);
+
+    /**
+     * @param string $namespace e.g. cms
+     * @param string $name e.g. duration_seconds
+     * @param string $help e.g. The duration something took in seconds.
+     * @param array  $labels e.g. ['controller', 'action']
+     *
+     * @return Gauge
+     */
+    public function getOrRegisterGauge($namespace, $name, $help, $labels = []);
+
+    /**
+     * @param string $namespace e.g. cms
+     * @param string $name e.g. requests
+     * @param string $help e.g. The number of requests made.
+     * @param array  $labels e.g. ['controller', 'action']
+     *
+     * @return Counter
+     * @throws MetricsRegistrationException
+     */
+    public function registerCounter($namespace, $name, $help, $labels = []);
+
+    /**
+     * @param string $namespace
+     * @param string $name
+     *
+     * @return Counter
+     * @throws MetricNotFoundException
+     */
+    public function getCounter($namespace, $name);
+
+    /**
+     * @param string $namespace e.g. cms
+     * @param string $name e.g. requests
+     * @param string $help e.g. The number of requests made.
+     * @param array  $labels e.g. ['controller', 'action']
+     *
+     * @return Counter
+     */
+    public function getOrRegisterCounter($namespace, $name, $help, $labels = []);
+
+    /**
+     * @param string $namespace e.g. cms
+     * @param string $name e.g. duration_seconds
+     * @param string $help e.g. A histogram of the duration in seconds.
+     * @param array  $labels e.g. ['controller', 'action']
+     * @param array  $buckets e.g. [100, 200, 300]
+     *
+     * @return Histogram
+     * @throws MetricsRegistrationException
+     */
+    public function registerHistogram($namespace, $name, $help, $labels = [], $buckets = null);
+
+    /**
+     * @param string $namespace
+     * @param string $name
+     *
+     * @return Histogram
+     * @throws MetricNotFoundException
+     */
+    public function getHistogram($namespace, $name);
+
+    /**
+     * @param string $namespace e.g. cms
+     * @param string $name e.g. duration_seconds
+     * @param string $help e.g. A histogram of the duration in seconds.
+     * @param array  $labels e.g. ['controller', 'action']
+     * @param array  $buckets e.g. [100, 200, 300]
+     *
+     * @return Histogram
+     */
+    public function getOrRegisterHistogram($namespace, $name, $help, $labels = [], $buckets = null);
+}
diff --git a/src/Prometheus/RenderTextFormat.php b/src/Prometheus/RenderTextFormat.php
index 95fe2b5..bf7e6a0 100644
--- a/src/Prometheus/RenderTextFormat.php
+++ b/src/Prometheus/RenderTextFormat.php
@@ -3,7 +3,7 @@
 namespace Prometheus;
 
 
-class RenderTextFormat
+class RenderTextFormat implements RendererInterface
 {
     const MIME_TYPE = 'text/plain; version=0.0.4';
 
diff --git a/src/Prometheus/RendererInterface.php b/src/Prometheus/RendererInterface.php
new file mode 100644
index 0000000..ad25258
--- /dev/null
+++ b/src/Prometheus/RendererInterface.php
@@ -0,0 +1,14 @@
+<?php
+declare(strict_types=1);
+
+namespace Prometheus;
+
+interface RendererInterface
+{
+    /**
+     * @param MetricFamilySamples[] $metrics
+     *
+     * @return string
+     */
+    public function render(array $metrics);
+}