Set default lag value to null (#217)

src/main/kotlin/io/emeraldpay/dshackle/quorum/NotLaggingQuorum.kt

@@ -55,7 +55,7 @@ class NotLaggingQuorum(val maxLag: Long = 0) : CallQuorum {
         upstream: Upstream,
         providedUpstreamId: String?
     ): Boolean {
-        val lagging = upstream.getLag() > maxLag
+        val lagging = upstream.getLag()?.run { this > maxLag } ?: true
         if (!lagging) {
             result.set(response)
             sig = signature
@@ -72,7 +72,7 @@ class NotLaggingQuorum(val maxLag: Long = 0) : CallQuorum {
         upstream: Upstream
     ) {
         this.rpcError = error.error
-        val lagging = upstream.getLag() > maxLag
+        val lagging = upstream.getLag()?.run { this > maxLag } ?: true
         if (!lagging && result.get() == null) {
             failed.set(true)
         }

src/main/kotlin/io/emeraldpay/dshackle/upstream/DefaultUpstream.kt

@@ -29,7 +29,7 @@ import java.util.concurrent.atomic.AtomicReference
 abstract class DefaultUpstream(
     private val id: String,
     private val hash: Byte,
-    defaultLag: Long,
+    defaultLag: Long?,
     defaultAvail: UpstreamAvailability,
     private val options: UpstreamsConfig.Options,
     private val role: UpstreamsConfig.UpstreamRole,
@@ -47,7 +47,7 @@ abstract class DefaultUpstream(
         node: QuorumForLabels.QuorumItem?,
         chainConfig: ChainsConfig.ChainConfig
     ) :
-        this(id, hash, Long.MAX_VALUE, UpstreamAvailability.UNAVAILABLE, options, role, targets, node, chainConfig)
+        this(id, hash, null, UpstreamAvailability.UNAVAILABLE, options, role, targets, node, chainConfig)
 
     protected val log = LoggerFactory.getLogger(this::class.java)
 
@@ -97,12 +97,15 @@ abstract class DefaultUpstream(
         }
     }
 
-    private fun statusByLag(lag: Long, proposed: UpstreamAvailability): UpstreamAvailability {
+    private fun statusByLag(lag: Long?, proposed: UpstreamAvailability): UpstreamAvailability {
         if (options.disableValidation) {
             // if we specifically told that this upstream should be _always valid_ then skip
             // the status calculation and trust the proposed value as is
             return proposed
         }
+        if (lag == null) {
+            return UpstreamAvailability.UNAVAILABLE
+        }
         return if (proposed == UpstreamAvailability.OK) {
             when {
                 lag > chainConfig.syncingLagSize -> UpstreamAvailability.SYNCING
@@ -140,7 +143,7 @@ abstract class DefaultUpstream(
         }
     }
 
-    override fun getLag(): Long {
+    override fun getLag(): Long? {
         return this.status.get().lag
     }
 
@@ -169,7 +172,7 @@ abstract class DefaultUpstream(
         return id
     }
 
-    data class Status(val lag: Long, val avail: UpstreamAvailability, val status: UpstreamAvailability)
+    data class Status(val lag: Long?, val avail: UpstreamAvailability, val status: UpstreamAvailability)
 
     private data class UpstreamChangeState(
         val status: UpstreamAvailability,

src/main/kotlin/io/emeraldpay/dshackle/upstream/Multistream.kt

@@ -122,7 +122,9 @@ abstract class Multistream(
         removeUpstreamMeters(upstreamId)
 
         meters[upstreamId] = listOf(
-            Gauge.builder("$metrics.lag", upstream) { it.getLag().toDouble() }
+            Gauge.builder("$metrics.lag", upstream) {
+                it.getLag()?.toDouble() ?: Double.NaN
+            }
                 .tag("chain", chain.chainCode)
                 .tag("upstream", upstreamId)
                 .register(Metrics.globalRegistry)
@@ -374,11 +376,7 @@ abstract class Multistream(
             // by default, when no lag is available it uses Long.MAX_VALUE, and it doesn't make sense to print
             // status with such value. use NA (as Not Available) instead
             val value = it.getLag()
-            if (value == Long.MAX_VALUE) {
-                "NA"
-            } else {
-                value.toString()
-            }
+            value?.toString() ?: "NA"
         }
         val weak = upstreams.plus(removed.values)
             .filter { it.getStatus() != UpstreamAvailability.OK }

src/main/kotlin/io/emeraldpay/dshackle/upstream/Upstream.kt

@@ -35,7 +35,7 @@ interface Upstream {
     fun getOptions(): UpstreamsConfig.Options
     fun getRole(): UpstreamsConfig.UpstreamRole
     fun setLag(lag: Long)
-    fun getLag(): Long
+    fun getLag(): Long?
     fun getLabels(): Collection<UpstreamsConfig.Labels>
     fun getMethods(): CallMethods
     fun getId(): String