CORDA-2669 - Reintroduce pendingFlowsCount (#4806) (#4807)

* CORDA-2669 - pendingFlowsCount not in public API

Reintroduce `pendingFlowsCount` to public API (as deprecated). Advise
to use the `gracefulShutdown` command in the shell instead.

* CORDA-2669 - Add pendingFlowsCount to api-current.txt

.ci/api-current.txt

@@ -3147,6 +3147,8 @@ public interface net.corda.core.messaging.CordaRPCOps extends net.corda.core.mes
   public abstract net.corda.core.identity.Party wellKnownPartyFromX500Name(net.corda.core.identity.CordaX500Name)
 ##
 public final class net.corda.core.messaging.CordaRPCOpsKt extends java.lang.Object
+  @NotNull
+  public static final net.corda.core.messaging.DataFeed<Integer, kotlin.Pair<Integer, Integer>> pendingFlowsCount(net.corda.core.messaging.CordaRPCOps)
 ##
 @CordaSerializable
 public final class net.corda.core.messaging.DataFeed extends java.lang.Object

core/src/main/kotlin/net/corda/core/messaging/CordaRPCOps.kt

@@ -22,6 +22,8 @@ import net.corda.core.serialization.CordaSerializable
 import net.corda.core.transactions.SignedTransaction
 import net.corda.core.utilities.Try
 import rx.Observable
+import rx.schedulers.Schedulers
+import rx.subjects.PublishSubject
 import java.io.IOException
 import java.io.InputStream
 import java.security.PublicKey
@@ -420,6 +422,38 @@ interface CordaRPCOps : RPCOps {
     fun isWaitingForShutdown(): Boolean
 }
 
+/**
+ * Returns a [DataFeed] of the number of pending flows. The [Observable] for the updates will complete the moment all pending flows will have terminated.
+ */
+@Deprecated("For automated upgrades, consider using the `gracefulShutdown` command in an SSH session instead.")
+fun CordaRPCOps.pendingFlowsCount(): DataFeed<Int, Pair<Int, Int>> {
+    val updates = PublishSubject.create<Pair<Int, Int>>()
+    val initialPendingFlowsCount = stateMachinesFeed().let {
+        var completedFlowsCount = 0
+        var pendingFlowsCount = it.snapshot.size
+        it.updates.observeOn(Schedulers.io()).subscribe({ update ->
+            when (update) {
+                is StateMachineUpdate.Added -> {
+                    pendingFlowsCount++
+                    updates.onNext(completedFlowsCount to pendingFlowsCount)
+                }
+                is StateMachineUpdate.Removed -> {
+                    completedFlowsCount++
+                    updates.onNext(completedFlowsCount to pendingFlowsCount)
+                    if (completedFlowsCount == pendingFlowsCount) {
+                        updates.onCompleted()
+                    }
+                }
+            }
+        }, updates::onError)
+        if (pendingFlowsCount == 0) {
+            updates.onCompleted()
+        }
+        pendingFlowsCount
+    }
+    return DataFeed(initialPendingFlowsCount, updates)
+}
+
 inline fun <reified T : ContractState> CordaRPCOps.vaultQueryBy(criteria: QueryCriteria = QueryCriteria.VaultQueryCriteria(),
                                                                 paging: PageSpecification = PageSpecification(),
                                                                 sorting: Sort = Sort(emptySet())): Vault.Page<T> {

node-api/src/main/kotlin/net/corda/nodeapi/internal/RpcHelpers.kt

@@ -1,45 +1,9 @@
 package net.corda.nodeapi.internal
 
 import net.corda.core.messaging.CordaRPCOps
-import net.corda.core.messaging.DataFeed
-import net.corda.core.messaging.StateMachineUpdate
 import rx.Observable
-import rx.schedulers.Schedulers
-import rx.subjects.PublishSubject
 import java.util.concurrent.TimeUnit
 
-/**
- * Returns a [DataFeed] of the number of pending flows. The [Observable] for the updates will complete the moment all pending flows will have terminated.
- */
-fun CordaRPCOps.pendingFlowsCount(): DataFeed<Int, Pair<Int, Int>> {
-
-    val updates = PublishSubject.create<Pair<Int, Int>>()
-    val initialPendingFlowsCount = stateMachinesFeed().let {
-        var completedFlowsCount = 0
-        var pendingFlowsCount = it.snapshot.size
-        it.updates.observeOn(Schedulers.io()).subscribe({ update ->
-            when (update) {
-                is StateMachineUpdate.Added -> {
-                    pendingFlowsCount++
-                    updates.onNext(completedFlowsCount to pendingFlowsCount)
-                }
-                is StateMachineUpdate.Removed -> {
-                    completedFlowsCount++
-                    updates.onNext(completedFlowsCount to pendingFlowsCount)
-                    if (completedFlowsCount == pendingFlowsCount) {
-                        updates.onCompleted()
-                    }
-                }
-            }
-        }, updates::onError)
-        if (pendingFlowsCount == 0) {
-            updates.onCompleted()
-        }
-        pendingFlowsCount
-    }
-    return DataFeed(initialPendingFlowsCount, updates)
-}
-
 /**
  * Returns an [Observable] that will complete when the node will have cancelled the draining shutdown hook.
  *

node/src/main/kotlin/net/corda/node/internal/CordaRPCOpsImpl.kt

@@ -35,7 +35,6 @@ import net.corda.node.services.rpc.context
 import net.corda.node.services.statemachine.StateMachineManager
 import net.corda.nodeapi.exceptions.NonRpcFlowException
 import net.corda.nodeapi.exceptions.RejectedCommandException
-import net.corda.nodeapi.internal.pendingFlowsCount
 import rx.Observable
 import rx.Subscription
 import java.io.InputStream

tools/shell/src/main/kotlin/net/corda/tools/shell/InteractiveShell.kt

@@ -19,11 +19,7 @@ import net.corda.core.flows.FlowLogic
 import net.corda.core.internal.*
 import net.corda.core.internal.concurrent.doneFuture
 import net.corda.core.internal.concurrent.openFuture
-import net.corda.core.messaging.CordaRPCOps
-import net.corda.core.messaging.DataFeed
-import net.corda.core.messaging.FlowProgressHandle
-import net.corda.core.messaging.StateMachineUpdate
-import net.corda.nodeapi.internal.pendingFlowsCount
+import net.corda.core.messaging.*
 import net.corda.tools.shell.utlities.ANSIProgressRenderer
 import net.corda.tools.shell.utlities.StdoutANSIProgressRenderer
 import org.crsh.command.InvocationContext