Fix metrics

src/main/kotlin/mdnet/ServerManager.kt

@@ -18,6 +18,8 @@ along with this MangaDex@Home.  If not, see <http://www.gnu.org/licenses/>.
 */
 package mdnet
 
+import io.micrometer.core.instrument.Gauge
+import io.micrometer.core.instrument.binder.BaseUnits
 import io.micrometer.prometheus.PrometheusConfig
 import io.micrometer.prometheus.PrometheusMeterRegistry
 import mdnet.cache.ImageStorage
@@ -105,7 +107,19 @@ class ServerManager(
 
     fun start() {
         LOGGER.info { "Image server starting" }
-        DefaultMicrometerMetrics(registry, storage.cacheDirectory)
+        DefaultMicrometerMetrics(registry)
+        Gauge.builder(
+            "cache.used",
+            storage,
+            { it.size.toDouble() }
+        ).baseUnit(BaseUnits.BYTES).register(registry)
+
+        Gauge.builder(
+            "cache.size",
+            storage,
+            { it.size.toDouble() }
+        ).baseUnit(BaseUnits.BYTES).register(registry)
+
         loginAndStartServer()
 
         var lastBytesSent = statistics.bytesSent.get()

src/main/kotlin/mdnet/cache/ImageStorage.kt

@@ -55,7 +55,7 @@ data class Image(val data: ImageMetadata, val stream: InputStream)
  */
 class ImageStorage(
     var maxSize: Long,
-    val cacheDirectory: Path,
+    private val cacheDirectory: Path,
     private val database: Database,
     autoPrune: Boolean = true
 ) {

src/main/kotlin/mdnet/metrics/DefaultMicrometerMetrics.kt

@@ -19,7 +19,6 @@ along with this MangaDex@Home.  If not, see <http://www.gnu.org/licenses/>.
 package mdnet.metrics
 
 import io.micrometer.core.instrument.Tag
-import io.micrometer.core.instrument.binder.jvm.DiskSpaceMetrics
 import io.micrometer.core.instrument.binder.jvm.JvmGcMetrics
 import io.micrometer.core.instrument.binder.jvm.JvmHeapPressureMetrics
 import io.micrometer.core.instrument.binder.jvm.JvmMemoryMetrics
@@ -30,9 +29,8 @@ import io.micrometer.core.instrument.binder.system.ProcessorMetrics
 import io.micrometer.core.instrument.binder.system.UptimeMetrics
 import io.micrometer.prometheus.PrometheusMeterRegistry
 import mdnet.BuildInfo
-import java.nio.file.Path
 
-class DefaultMicrometerMetrics(registry: PrometheusMeterRegistry, cacheDirectory: Path) {
+class DefaultMicrometerMetrics(registry: PrometheusMeterRegistry) {
     init {
         UptimeMetrics(
             mutableListOf(
@@ -47,6 +45,5 @@ class DefaultMicrometerMetrics(registry: PrometheusMeterRegistry, cacheDirectory
         JvmHeapPressureMetrics().bindTo(registry)
         FileDescriptorMetrics().bindTo(registry)
         LogbackMetrics().bindTo(registry)
-        DiskSpaceMetrics(cacheDirectory.toFile()).bindTo(registry)
     }
 }

src/main/kotlin/mdnet/server/ImageServer.kt

@@ -22,6 +22,7 @@ import io.github.resilience4j.circuitbreaker.CircuitBreakerConfig
 import io.github.resilience4j.circuitbreaker.CircuitBreakerRegistry
 import io.github.resilience4j.micrometer.tagged.TaggedCircuitBreakerMetrics
 import io.micrometer.core.instrument.FunctionCounter
+import io.micrometer.core.instrument.binder.BaseUnits
 import io.micrometer.prometheus.PrometheusMeterRegistry
 import mdnet.cache.ImageStorage
 import mdnet.data.Statistics
@@ -98,10 +99,10 @@ fun getServer(
     )
 
     FunctionCounter.builder(
-        "client_sent_bytes",
+        "client.sent.bytes",
         statistics,
         { it.bytesSent.get().toDouble() }
-    ).register(registry)
+    ).baseUnit(BaseUnits.BYTES).register(registry)
 
     val verifier = TokenVerifier(
         tokenKey = remoteSettings.tokenKey,