SERVER-20283 Update connPoolStats command to include multiple connection pools

12 files changed, 110 insertions, 5 deletions

diff --git a/src/mongo/executor/connection_pool.cpp b/src/mongo/executor/connection_pool.cpp
index 0fb0e1ded00..aa5e995600b 100644
--- a/src/mongo/executor/connection_pool.cpp
+++ b/src/mongo/executor/connection_pool.cpp
@@ -29,6 +29,7 @@
 
 #include "mongo/executor/connection_pool.h"
 
+#include "mongo/bson/bsonobjbuilder.h"
 #include "mongo/stdx/memory.h"
 #include "mongo/util/assert_util.h"
 #include "mongo/util/scopeguard.h"
@@ -57,7 +58,7 @@ public:
     ~SpecificPool();
 
     /**
-     * Get's a connection from the specific pool. Sinks a unique_lock from the
+     * Gets a connection from the specific pool. Sinks a unique_lock from the
      * parent to preserve the lock on _mutex
      */
     void getConnection(const HostAndPort& hostAndPort,
@@ -66,7 +67,7 @@ public:
                        GetConnectionCallback cb);
 
     /**
-     * Cascade a failure across existing connections and requests. Invoking
+     * Cascades a failure across existing connections and requests. Invoking
      * this function drops all current connections and fails all current
      * requests with the passed status.
      */
@@ -78,6 +79,21 @@ public:
      */
     void returnConnection(ConnectionInterface* connection, stdx::unique_lock<stdx::mutex> lk);
 
+    /**
+     * Returns the number of connections currently checked out of the pool.
+     */
+    size_t inUseConnections(const stdx::unique_lock<stdx::mutex>& lk);
+
+    /**
+     * Returns the number of available connections in the pool.
+     */
+    size_t availableConnections(const stdx::unique_lock<stdx::mutex>& lk);
+
+    /**
+     * Returns the total number of connections ever created in this pool.
+     */
+    size_t createdConnections(const stdx::unique_lock<stdx::mutex>& lk);
+
 private:
     using OwnedConnection = std::unique_ptr<ConnectionInterface>;
     using OwnershipPool = std::unordered_map<ConnectionInterface*, OwnedConnection>;
@@ -118,6 +134,8 @@ private:
     size_t _generation;
     bool _inFulfillRequests;
 
+    size_t _created;
+
     /**
      * The current state of the pool
      *
@@ -187,6 +205,44 @@ void ConnectionPool::get(const HostAndPort& hostAndPort,
     pool->getConnection(hostAndPort, timeout, std::move(lk), std::move(cb));
 }
 
+void ConnectionPool::appendConnectionStats(BSONObjBuilder* b) {
+    size_t inUse = 0u;
+    size_t available = 0u;
+    size_t created = 0u;
+
+    BSONObjBuilder hostBuilder(b->subobjStart("hosts"));
+
+    stdx::unique_lock<stdx::mutex> lk(_mutex);
+
+    for (const auto& kv : _pools) {
+        std::string label = kv.first.toString();
+        BSONObjBuilder hostInfo(hostBuilder.subobjStart(label));
+
+        auto& pool = kv.second;
+        auto inUseConnections = pool->inUseConnections(lk);
+        auto availableConnections = pool->availableConnections(lk);
+        auto createdConnections = pool->createdConnections(lk);
+        hostInfo.appendNumber("inUse", inUseConnections);
+        hostInfo.appendNumber("available", availableConnections);
+        hostInfo.appendNumber("created", createdConnections);
+
+        hostInfo.done();
+
+        // update available and created
+        inUse += inUseConnections;
+        available += availableConnections;
+        created += createdConnections;
+    }
+
+    hostBuilder.done();
+
+    b->appendNumber("totalInUse", inUse);
+    b->appendNumber("totalAvailable", available);
+    b->appendNumber("totalCreated", created);
+
+    return;
+}
+
 void ConnectionPool::returnConnection(ConnectionInterface* conn) {
     stdx::unique_lock<stdx::mutex> lk(_mutex);
 
@@ -203,12 +259,26 @@ ConnectionPool::SpecificPool::SpecificPool(ConnectionPool* parent, const HostAnd
       _requestTimer(parent->_factory->makeTimer()),
       _generation(0),
       _inFulfillRequests(false),
+      _created(0),
       _state(State::kRunning) {}
 
 ConnectionPool::SpecificPool::~SpecificPool() {
     DESTRUCTOR_GUARD(_requestTimer->cancelTimeout();)
 }
 
+size_t ConnectionPool::SpecificPool::inUseConnections(const stdx::unique_lock<stdx::mutex>& lk) {
+    return _checkedOutPool.size();
+}
+
+size_t ConnectionPool::SpecificPool::availableConnections(
+    const stdx::unique_lock<stdx::mutex>& lk) {
+    return _readyPool.size();
+}
+
+size_t ConnectionPool::SpecificPool::createdConnections(const stdx::unique_lock<stdx::mutex>& lk) {
+    return _created;
+}
+
 void ConnectionPool::SpecificPool::getConnection(const HostAndPort& hostAndPort,
                                                  Milliseconds timeout,
                                                  stdx::unique_lock<stdx::mutex> lk,
@@ -414,6 +484,8 @@ void ConnectionPool::SpecificPool::spawnConnections(stdx::unique_lock<stdx::mute
         auto connPtr = handle.get();
         _processingPool[connPtr] = std::move(handle);
 
+        ++_created;
+
         // Run the setup callback
         lk.unlock();
         connPtr->setup(_parent->_options.refreshTimeout,
diff --git a/src/mongo/executor/connection_pool.h b/src/mongo/executor/connection_pool.h
index d46b18b9812..a5d1676bf0e 100644
--- a/src/mongo/executor/connection_pool.h
+++ b/src/mongo/executor/connection_pool.h
@@ -38,6 +38,9 @@
 #include "mongo/util/net/hostandport.h"
 
 namespace mongo {
+
+class BSONObjBuilder;
+
 namespace executor {
 
 /**
@@ -110,9 +113,7 @@ public:
 
     void get(const HostAndPort& hostAndPort, Milliseconds timeout, GetConnectionCallback cb);
 
-    /**
-     * TODO add a function returning connection pool stats
-     */
+    void appendConnectionStats(BSONObjBuilder* b);
 
 private:
     void returnConnection(ConnectionInterface* connection);
diff --git a/src/mongo/executor/network_interface.h b/src/mongo/executor/network_interface.h
index 8b151b5b54e..8776506b0fe 100644
--- a/src/mongo/executor/network_interface.h
+++ b/src/mongo/executor/network_interface.h
@@ -36,6 +36,9 @@
 #include "mongo/stdx/functional.h"
 
 namespace mongo {
+
+class BSONObjBuilder;
+
 namespace executor {
 
 /**
@@ -59,6 +62,11 @@ public:
     virtual std::string getDiagnosticString() = 0;
 
     /**
+     * Appends connection information to the provided BSONObjBuilder.
+     */
+    virtual void appendConnectionStats(BSONObjBuilder* b) = 0;
+
+    /**
      * Starts up the network interface.
      *
      * It is valid to call all methods except shutdown() before this method completes.  That is,
diff --git a/src/mongo/executor/network_interface_asio.cpp b/src/mongo/executor/network_interface_asio.cpp
index 0379738ee93..19f38107de6 100644
--- a/src/mongo/executor/network_interface_asio.cpp
+++ b/src/mongo/executor/network_interface_asio.cpp
@@ -90,6 +90,10 @@ std::string NetworkInterfaceASIO::getDiagnosticString() {
     return output;
 }
 
+void NetworkInterfaceASIO::appendConnectionStats(BSONObjBuilder* b) {
+    _connectionPool.appendConnectionStats(b);
+}
+
 std::string NetworkInterfaceASIO::getHostName() {
     return getHostNameCached();
 }
diff --git a/src/mongo/executor/network_interface_asio.h b/src/mongo/executor/network_interface_asio.h
index 2c44039b48c..91fc0858824 100644
--- a/src/mongo/executor/network_interface_asio.h
+++ b/src/mongo/executor/network_interface_asio.h
@@ -100,6 +100,7 @@ public:
     NetworkInterfaceASIO(Options = Options());
 
     std::string getDiagnosticString() override;
+    void appendConnectionStats(BSONObjBuilder* b) override;
     std::string getHostName() override;
     void startup() override;
     void shutdown() override;
diff --git a/src/mongo/executor/network_interface_impl.cpp b/src/mongo/executor/network_interface_impl.cpp
index 869ea22d0b2..e7eb502e320 100644
--- a/src/mongo/executor/network_interface_impl.cpp
+++ b/src/mongo/executor/network_interface_impl.cpp
@@ -87,6 +87,8 @@ std::string NetworkInterfaceImpl::getDiagnosticString() {
     return output;
 }
 
+void NetworkInterfaceImpl::appendConnectionStats(BSONObjBuilder* b) {}
+
 void NetworkInterfaceImpl::startup() {
     stdx::unique_lock<stdx::mutex> lk(_mutex);
     invariant(!_inShutdown);
diff --git a/src/mongo/executor/network_interface_impl.h b/src/mongo/executor/network_interface_impl.h
index 793e574a552..bc422c59be0 100644
--- a/src/mongo/executor/network_interface_impl.h
+++ b/src/mongo/executor/network_interface_impl.h
@@ -77,6 +77,7 @@ public:
     NetworkInterfaceImpl(std::unique_ptr<NetworkConnectionHook> hook);
     ~NetworkInterfaceImpl();
     std::string getDiagnosticString() override;
+    void appendConnectionStats(BSONObjBuilder* b) override;
     void startup() override;
     void shutdown() override;
     void waitForWork() override;
diff --git a/src/mongo/executor/network_interface_mock.cpp b/src/mongo/executor/network_interface_mock.cpp
index d62b13d87ae..fe0aef336be 100644
--- a/src/mongo/executor/network_interface_mock.cpp
+++ b/src/mongo/executor/network_interface_mock.cpp
@@ -63,6 +63,8 @@ std::string NetworkInterfaceMock::getDiagnosticString() {
     return "NetworkInterfaceMock diagnostics here";
 }
 
+void NetworkInterfaceMock::appendConnectionStats(BSONObjBuilder* b) {}
+
 Date_t NetworkInterfaceMock::now() {
     stdx::lock_guard<stdx::mutex> lk(_mutex);
     return _now_inlock();
diff --git a/src/mongo/executor/network_interface_mock.h b/src/mongo/executor/network_interface_mock.h
index 0b231295595..8272bf84509 100644
--- a/src/mongo/executor/network_interface_mock.h
+++ b/src/mongo/executor/network_interface_mock.h
@@ -75,6 +75,7 @@ public:
 
     NetworkInterfaceMock();
     virtual ~NetworkInterfaceMock();
+    virtual void appendConnectionStats(BSONObjBuilder* b);
     virtual std::string getDiagnosticString();
 
     ////////////////////////////////////////////////////////////////////////////////
diff --git a/src/mongo/executor/task_executor.h b/src/mongo/executor/task_executor.h
index 74ba98048c4..be7d61b6a1b 100644
--- a/src/mongo/executor/task_executor.h
+++ b/src/mongo/executor/task_executor.h
@@ -43,6 +43,7 @@
 
 namespace mongo {
 
+class BSONObjBuilder;
 class OperationContext;
 
 namespace executor {
@@ -230,6 +231,12 @@ public:
      */
     virtual void wait(const CallbackHandle& cbHandle) = 0;
 
+    /**
+     * Appends information about the underlying network interface's connections to the given
+     * builder.
+     */
+    virtual void appendConnectionStats(BSONObjBuilder* b) = 0;
+
 protected:
     TaskExecutor();
 
diff --git a/src/mongo/executor/thread_pool_task_executor.cpp b/src/mongo/executor/thread_pool_task_executor.cpp
index d70c89abfd4..dae256abc09 100644
--- a/src/mongo/executor/thread_pool_task_executor.cpp
+++ b/src/mongo/executor/thread_pool_task_executor.cpp
@@ -342,6 +342,10 @@ void ThreadPoolTaskExecutor::wait(const CallbackHandle& cbHandle) {
     waitForEvent(cbState->finishedEvent);
 }
 
+void ThreadPoolTaskExecutor::appendConnectionStats(BSONObjBuilder* b) {
+    _net->appendConnectionStats(b);
+}
+
 void ThreadPoolTaskExecutor::cancelAllCommands() {
     _net->cancelAllCommands();
 }
diff --git a/src/mongo/executor/thread_pool_task_executor.h b/src/mongo/executor/thread_pool_task_executor.h
index e709440dd92..e983c91de49 100644
--- a/src/mongo/executor/thread_pool_task_executor.h
+++ b/src/mongo/executor/thread_pool_task_executor.h
@@ -80,6 +80,8 @@ public:
     void cancel(const CallbackHandle& cbHandle) override;
     void wait(const CallbackHandle& cbHandle) override;
 
+    void appendConnectionStats(BSONObjBuilder* b) override;
+
     /**
      * Cancels all commands on the network interface.
      */