expose battery percentage

client/app/src/main/java/com/birdthedeveloper/prometheus/android/prometheus/android/exporter/AndroidCustomExporter.kt

@@ -7,35 +7,27 @@ import kotlinx.coroutines.runBlocking
 import java.util.Arrays
 import kotlinx.coroutines.*
 
-class AndroidCustomExporter(name: String) : Collector() {
+class AndroidCustomExporter(metricEngine: MetricsEngine) : Collector() {
+    private val metricsEngineRef = metricEngine
 
-
-//TODO pass context here, get baterry percentage from metrics engine
     override fun collect(): List<MetricFamilySamples> {
         val mfs: MutableList<MetricFamilySamples> = ArrayList()
-        // With no labels.
-        mfs.add(GaugeMetricFamily("my_gauge", "help", 42.0))
-        // With labels
-        val labeledGauge = GaugeMetricFamily("my_other_gauge", "help", Arrays.asList("labelname"))
-        labeledGauge.addMetric(listOf("foo"), 4.0)
-        labeledGauge.addMetric(listOf("bar"), 5.0)
-        mfs.add(labeledGauge)
-        println("Start blocking")
+
+        // metrics definitions
+        collectBatteryStatus(mfs)
+
         return mfs
     }
 
-    fun collectBaterryStatus(mfs: MutableList<MetricFamilySamples>) {
+    fun collectBatteryStatus(mfs: MutableList<MetricFamilySamples>) {
         //TODO
-        val baterryPercentageGauge = GaugeMetricFamily(
-            "baterry_percentage",
-            "Baterry percentage", listOf(),
+        val batteryPercentageGauge = GaugeMetricFamily(
+            "battery_percentage",
+            "Current battery percentage", listOf(),
         )
 
-
-
-        //baterryPercentageGauge.addMetric()
-
-
+        val batteryPercentage : Double = metricsEngineRef.getBatteryPercentage().toDouble()
+        batteryPercentageGauge.addMetric(listOf(), batteryPercentage)
+        mfs.add(batteryPercentageGauge)
     }
-
-}
+}

client/app/src/main/java/com/birdthedeveloper/prometheus/android/prometheus/android/exporter/MainActivity.kt

@@ -1,6 +1,7 @@
 package com.birdthedeveloper.prometheus.android.prometheus.android.exporter
 
 import android.os.Bundle
+import android.text.BoringLayout.Metrics
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
 import androidx.compose.foundation.layout.fillMaxSize
@@ -22,13 +23,14 @@ import java.io.StringWriter
 
 class MainActivity : ComponentActivity() {
 
-    // register custom prometheus exporter
-    val collectorRegistry: CollectorRegistry = CollectorRegistry()
-    val customExporter: AndroidCustomExporter = AndroidCustomExporter("dummy")
-        .register(collectorRegistry)
+    private val collectorRegistry: CollectorRegistry = CollectorRegistry()
+    private lateinit var metricsEngine: MetricsEngine
+    private lateinit var customExporter: AndroidCustomExporter
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
+        initialize()
+
         setContent {
             PrometheusAndroidExporterTheme {
                 // A surface container using the 'background' color from the theme
@@ -42,6 +44,11 @@ class MainActivity : ComponentActivity() {
         }
     }
 
+    private fun initialize (){
+        metricsEngine = MetricsEngine(this.applicationContext)
+        customExporter = AndroidCustomExporter(metricsEngine).register(collectorRegistry)
+    }
+
     fun CollectMetrics(): String{
         val writer = StringWriter()
         TextFormat.write004(writer, collectorRegistry.metricFamilySamples())

client/app/src/main/java/com/birdthedeveloper/prometheus/android/prometheus/android/exporter/MetricsEngine.kt

@@ -1,12 +1,25 @@
 package com.birdthedeveloper.prometheus.android.prometheus.android.exporter
 
+import android.content.Context
 import android.content.Intent
 import android.content.IntentFilter
+import android.os.BatteryManager
 
-class MetricsEngine {
-//    public fun getBatteryPercentage(){
-//        val batteryStatus: Intent? = IntentFilter(Intent.ACTION_BATTERY_CHANGED).let { ifilter ->
-//            context.registerReceiver(null, ifilter)
-//        }
-//    }
-}
+class MetricsEngine(context: Context) {
+    private val contextRef = context
+    public fun getBatteryPercentage() : Float{
+        val batteryStatus: Intent? = IntentFilter(Intent.ACTION_BATTERY_CHANGED).let { intFilter ->
+            contextRef.registerReceiver(null, intFilter)
+        }
+        //val status: Int = batteryStatus?.getIntExtra(BatteryManager.EXTRA_STATUS, -1) ?: -1
+
+        val batteryPct: Float? = batteryStatus?.let { intent ->
+            val level: Int = intent.getIntExtra(BatteryManager.EXTRA_LEVEL, -1)
+            val scale: Int = intent.getIntExtra(BatteryManager.EXTRA_SCALE, -1)
+            level * 100 / scale.toFloat()
+        }
+
+        batteryPct?: return -1.0f
+        return batteryPct
+    }
+}