Merge pull request #1534 from Expensify/ionatan_notifyplugins

Add notifyPlugins method

BedrockPlugin.h

@@ -76,6 +76,9 @@ class BedrockPlugin {
     // re-open those connections if not handled elsewhere in the plugin.
     virtual void onAttach() {}
 
+    // Called when a node changes state
+    virtual void stateChanged(SQLite& db, SQLiteNodeState newState) {}
+
     // Map of plugin names to functions that will return a new plugin of the given type.
     static map<string, function<BedrockPlugin*(BedrockServer&)>> g_registeredPluginList;
 

BedrockServer.cpp

@@ -2356,3 +2356,9 @@ void BedrockServer::waitForHTTPS(unique_ptr<BedrockCommand>&& command) {
 const atomic<SQLiteNodeState>& BedrockServer::getState() const {
     return _nodeStateSnapshot == SQLiteNodeState::UNKNOWN ? _replicationState : _nodeStateSnapshot;
 }
+
+void BedrockServer::notifyStateChangeToPlugins(SQLite& db, SQLiteNodeState newState) {
+    for (auto plugin : plugins) {
+        plugin.second->stateChanged(db, newState);
+    }
+}

BedrockServer.h

@@ -497,4 +497,7 @@ class BedrockServer : public SQLiteServer {
     // syncNode while the sync thread exists, it's a shared pointer to allow for the last socket thread using it to
     // destroy the pool at shutdown.
     shared_ptr<SQLitePool> _dbPool;
+
+    // We call this method whenever a node changes state
+    void notifyStateChangeToPlugins(SQLite& db, SQLiteNodeState newState) override;
 };

sqlitecluster/SQLiteNode.cpp

@@ -1809,6 +1809,9 @@ void SQLiteNode::_changeState(SQLiteNodeState newState) {
     _localCommitNotifier.notifyThrough(_db.getCommitCount());
 
     if (newState != _state) {
+        // First, we notify all plugins about the state change
+        _server.notifyStateChangeToPlugins(_db, newState);
+
         // If we were following, and now we're not, we give up an any replications.
         if (_state == SQLiteNodeState::FOLLOWING) {
             _replicationThreadsShouldExit = true;

sqlitecluster/SQLiteServer.h

@@ -14,4 +14,7 @@ class SQLiteServer : public STCPManager {
 
     // When a node connects to the cluster, this function will be called on the sync thread.
     virtual void onNodeLogin(SQLitePeer* peer) = 0;
+
+    // We call this method whenever a node changes state
+    virtual void notifyStateChangeToPlugins(SQLite& db, SQLiteNodeState newState) = 0;
 };

test/tests/SQLiteNodeTest.cpp

@@ -25,6 +25,7 @@ class TestServer : public SQLiteServer {
 
     virtual bool canStandDown() { return true; }
     virtual void onNodeLogin(SQLitePeer* peer) { }
+    virtual void notifyStateChangeToPlugins(SQLite& db, SQLiteNodeState newState) {}
 };
 
 struct SQLiteNodeTest : tpunit::TestFixture {