Add type to local/remote error metrics (#3249)

We were only splitting by origin (local/remote).

This compensates for #3236.

Author: pm47

eclair-core/src/main/scala/fr/acinq/eclair/channel/Monitoring.scala

@@ -86,6 +86,7 @@ object Monitoring {
     val Direction = "direction"
     val Event = "event"
     val Fatal = "fatal"
+    val ErrorType = "error-type"
     val Origin = "origin"
     val State = "state"
     val CommitmentFormat = "commitment-format"

eclair-core/src/main/scala/fr/acinq/eclair/db/DbEventHandler.scala

@@ -30,6 +30,7 @@ import fr.acinq.eclair.db.DbEventHandler.ChannelEvent
 import fr.acinq.eclair.payment.Monitoring.{Metrics => PaymentMetrics, Tags => PaymentTags}
 import fr.acinq.eclair.payment._
 import fr.acinq.eclair.{Logs, NodeParams, TimestampMilli}
+import kamon.tag.TagSet
 
 /**
  * This actor sits at the interface between our event stream and the database.
@@ -112,10 +113,17 @@ class DbEventHandler(nodeParams: NodeParams) extends Actor with DiagnosticActorL
       // The first pattern matching level is to ignore some errors, the second level is to separate between different kind of errors.
       e.error match {
         case LocalError(_: CannotAffordFees) => () // will be thrown at each new block if our balance is too low to update the commitment fee
-        case _ => e.error match {
-          case LocalError(_) => ChannelMetrics.ChannelErrors.withTag(ChannelTags.Origin, ChannelTags.Origins.Local).withTag(ChannelTags.Fatal, value = e.isFatal).increment()
-          case RemoteError(_) => ChannelMetrics.ChannelErrors.withTag(ChannelTags.Origin, ChannelTags.Origins.Remote).increment()
-        }
+        case _ =>
+          val tags = e.error match {
+            case LocalError(t) => TagSet.Empty
+              .withTag(ChannelTags.Origin, ChannelTags.Origins.Local)
+              .withTag(ChannelTags.Fatal, value = e.isFatal)
+              .withTag(ChannelTags.ErrorType, t.getClass.getSimpleName)
+            case RemoteError(_) => TagSet.Empty
+              .withTag(ChannelTags.Origin, ChannelTags.Origins.Remote)
+              .withTag(ChannelTags.Fatal, value = true) // remote errors are always fatal
+          }
+          ChannelMetrics.ChannelErrors.withTags(tags).increment()
       }
 
     case e: ChannelStateChanged =>