Log block queue status in BlockChainSync

Log the block queue status when BlockChainSync cannot sync with a peer due to syncing being paused and when it cannot request blocks due to the block queue being full.

Also convert some BlockQueue constants to constexpr and wrap checking for a paused sync in a helper function (BlockChainSync::isSyncPaused) in the interest of consistency since pausing a sync is done via a helper function (BlockChainSync::pauseSync).

libethereum/BlockChainSync.cpp

@@ -236,8 +236,13 @@ void BlockChainSync::syncPeer(NodeID const& _peerID, bool _force)
         return;
     }
 
-    if (m_state == SyncState::Waiting)
+    if (isSyncPaused())
+    {
+        LOG(m_loggerDetail) << "Can't sync with peer " << _peerID
+                            << " - sync state is paused. Block queue status: "
+                            << host().bq().status();
         return;
+    }
 
     u256 td = host().chain().details().totalDifficulty;
     if (host().bq().isActive())
@@ -284,7 +289,9 @@ void BlockChainSync::requestBlocks(NodeID const& _peerID)
     clearPeerDownload(_peerID);
     if (host().bq().knownFull())
     {
-        LOG(m_loggerDetail) << "Waiting for block queue before downloading blocks";
+        LOG(m_loggerDetail)
+            << "Waiting for block queue before downloading blocks. Block queue status: "
+            << host().bq().status();
         pauseSync();
         return;
     }
@@ -861,11 +868,6 @@ void BlockChainSync::completeSync()
     m_state = SyncState::Idle;
 }
 
-void BlockChainSync::pauseSync()
-{
-    m_state = SyncState::Waiting;
-}
-
 bool BlockChainSync::isSyncing() const
 {
     return m_state != SyncState::Idle;

libethereum/BlockChainSync.h

@@ -75,7 +75,8 @@ class BlockChainSync final: public HasInvariants
     void continueSync();
 
     /// Enter waiting state
-    void pauseSync();
+    void pauseSync() { m_state = SyncState::Waiting; }
+    bool isSyncPaused() { return m_state == SyncState::Waiting; }
 
     EthereumCapability& host() { return m_host; }
     EthereumCapability const& host() const { return m_host; }

libethereum/BlockQueue.cpp

@@ -32,10 +32,10 @@ using namespace std;
 using namespace dev;
 using namespace dev::eth;
 
-size_t const c_maxKnownCount = 100000;
-size_t const c_maxKnownSize = 128 * 1024 * 1024;
-size_t const c_maxUnknownCount = 100000;
-size_t const c_maxUnknownSize = 512 * 1024 * 1024; // Block size can be ~50kb
+constexpr size_t c_maxKnownCount = 100000;
+constexpr size_t c_maxKnownSize = 128 * 1024 * 1024;
+constexpr size_t c_maxUnknownCount = 100000;
+constexpr size_t c_maxUnknownSize = 512 * 1024 * 1024;  // Block size can be ~50kb
 
 BlockQueue::BlockQueue()
 {
@@ -514,7 +514,8 @@ void BlockQueue::retryAllUnknown()
     m_moreToVerify.notify_all();
 }
 
-std::ostream& dev::eth::operator<<(std::ostream& _out, BlockQueueStatus const& _bqs)
+boost::log::formatting_ostream& dev::eth::operator<<(
+    boost::log::formatting_ostream& _out, BlockQueueStatus const& _bqs)
 {
     _out << "importing: " << _bqs.importing << endl;
     _out << "verified: " << _bqs.verified << endl;

libethereum/BlockQueue.h

@@ -328,7 +328,7 @@ class BlockQueue: HasInvariants
     Logger m_loggerDetail{createLogger(VerbosityTrace, "bq")};
 };
 
-std::ostream& operator<<(std::ostream& _out, BlockQueueStatus const& _s);
-
+boost::log::formatting_ostream& operator<<(
+    boost::log::formatting_ostream& _out, BlockQueueStatus const& _s);
 }
 }