This fix ensures all redis DB is flushed before any GetSeq calls are …

…sent by the generators. This is needed because we can have the following sequence in the collector that can lead to a crash viz., generator issues GetSeq, collector to redis connection post process call resulting in Flush of database, DeleteUVE request from the generator due to disconnect session. The above sequence tries to delete a UVE thats not there in Redis. This fix prevents such a case from happening.

Closes-Bug:#1670908
Change-Id: I51dfedacdac75fdf5b271cdcaaafb7d4ddfd9bfc

src/analytics/OpServerProxy.cc

@@ -294,6 +294,7 @@ class OpServerProxy::OpServerImpl {
                 tbb::mutex::scoped_lock lock(rac_mutex_);
                 redis_uve_.RedisStatusUpdate(RAC_DOWN);
             }
+            started_ = false;
             collector_->RedisUpdate(false);
             kafka_proc_->SetRedisState(false);
 
@@ -466,6 +467,8 @@ class OpServerProxy::OpServerImpl {
 
         RedisInfo redis_uve_;
 
+        bool IsInitDone() { return started_;}
+
     private:
         EventManager *evm_;
         VizCollector *collector_;
@@ -704,3 +707,13 @@ RedisUVERequest::HandleRequest() const {
     resp->Response();
 }
 
+/*
+ * After redis collector connection is UP,
+ * we do initialization as part of a callback.
+ * We set the started_ flag during that step.
+ */
+bool
+OpServerProxy::IsRedisInitDone() {
+    return impl_->IsInitDone();
+}
+

src/analytics/OpServerProxy.h

@@ -68,6 +68,7 @@ class OpServerProxy {
                             const std::string &instance_id);
 
     void FillRedisUVEInfo(RedisUveInfo& redis_uve_info);
+    virtual bool IsRedisInitDone();
 private:
     class OpServerImpl;
     OpServerImpl *impl_;

src/analytics/collector.cc

@@ -209,7 +209,10 @@ bool Collector::ReceiveSandeshCtrlMsg(SandeshStateMachine *state_machine,
             snh->get_source() << ":" << snh->get_module_name());
         return false;
     }
-
+    if (!osp_->IsRedisInitDone()) {
+        LOG(ERROR, "Collector connection to redis is not establised and flush done");
+        return false;
+    }
     SandeshGenerator::GeneratorId id(boost::make_tuple(snh->get_source(),
             snh->get_module_name(), snh->get_instance_id_name(),
             snh->get_node_type_name()));