merge: Expose metrics directly to user (#80)

This pull request adds the ability to access the metrics of resources modeled
by the OpenDC Compute, Workflow, FaaS, and TensorFlow services directly from
their corresponding interfaces. Previously, users would have to interact with
OpenTelemetry to obtain these values, which is complex and provides
significant overhead.

With this pull request, users can access the metrics of all cloud resources
modeled by OpenDC via methods such as `getSchedulerStats()`, etc.

** Breaking Changes **

- `ComputeService.hostCount` removed in favour of `ComputeService.hosts.size`

1 files changed, 8 insertions, 1 deletions

diff --git a/opendc-experiments/opendc-experiments-tf20/src/test/kotlin/org/opendc/experiments/tf20/core/SimTFDeviceTest.kt b/opendc-experiments/opendc-experiments-tf20/src/test/kotlin/org/opendc/experiments/tf20/core/SimTFDeviceTest.kt
index 28a2a319..0d5fbebb 100644
--- a/opendc-experiments/opendc-experiments-tf20/src/test/kotlin/org/opendc/experiments/tf20/core/SimTFDeviceTest.kt
+++ b/opendc-experiments/opendc-experiments-tf20/src/test/kotlin/org/opendc/experiments/tf20/core/SimTFDeviceTest.kt
@@ -25,6 +25,7 @@ package org.opendc.experiments.tf20.core
 import io.opentelemetry.api.metrics.MeterProvider
 import kotlinx.coroutines.coroutineScope
 import kotlinx.coroutines.launch
+import org.junit.jupiter.api.Assertions.assertAll
 import org.junit.jupiter.api.Assertions.assertEquals
 import org.junit.jupiter.api.Test
 import org.opendc.simulator.compute.model.MemoryUnit
@@ -57,6 +58,12 @@ internal class SimTFDeviceTest {
             launch { device.compute(1e6) }
             launch { device.compute(2e6) }
         }
-        assertEquals(3681, clock.millis())
+
+        val stats = device.getDeviceStats()
+
+        assertAll(
+            { assertEquals(3681, clock.millis()) },
+            { assertEquals(325.75, stats.energyUsage) }
+        )
     }
 }