Add support for config file parsing and watching

[ric-plt/xapp-frame-cpp.git] / examples / xapp_t3.cpp

diff --git a/examples/xapp_t3.cpp b/examples/xapp_t3.cpp
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+// vi: ts=4 sw=4 noet:
+/*
+==================================================================================
+       Copyright (c) 2020 Nokia
+       Copyright (c) 2020 AT&T Intellectual Property.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+==================================================================================
+*/
+
+/*
+       Mnemonic:       xapp_t3.cpp
+       Abstract:       This is a simple xAPP which includes using the config support
+                               in the framework.  It is based on the xapp_t1 example and doesn't
+                               do much more than that.
+
+       Date:           30 July 2020
+       Author:         E. Scott Daniels
+
+       Caution:        This example code is pulled directly into one or more of the documents
+                               (starting from the "start-example" tag below.  Use caution with
+                               line lengths and contents because of the requirement that this
+                               be documentation as well as working code.
+*/
+// start-example
+#include <stdio.h>
+
+#include "ricxfcpp/config.hpp"
+#include "ricxfcpp/message.hpp"
+#include "ricxfcpp/msg_component.hpp"
+#include <ricxfcpp/metrics.hpp>
+#include "ricxfcpp/xapp.hpp"
+
+int vlevel = 0;                                        // verbose mode set via config
+
+/*
+       Just print something to the tty when we receive a message
+       and are in verbose mode.
+*/
+void cb1( xapp::Message& mbuf, int mtype, int subid, int len,
+                       xapp::Msg_component payload,  void* data ) {
+       if( vlevel > 0 ) {
+               fprintf( stdout, "message received is %d bytes long\n", len );
+       }
+}
+
+/*
+       Driven when the configuration changes. We snarf the verbose
+       level from the new config and update it. If it changed to
+       >0, incoming messages should be recorded with a tty message.
+       If set to 0, then tty output will be disabled.
+*/
+void config_cb( xapp::Config& c, void* data ) {
+       int* vp;
+
+       if( (vp = (int *) data) != NULL ) {
+               *vp = c.Get_control_value( "verbose_level", *vp );
+       }
+}
+
+int main( int argc, char** argv ) {
+       Xapp*   x;
+       int             nthreads = 1;
+       std::unique_ptr<xapp::Config> cfg;
+
+       // only parameter recognised is the config file name
+       if( argc > 1 ) {
+               cfg = std::unique_ptr<xapp::Config>( new xapp::Config( std::string( argv[1] ) ) );
+       } else {
+               cfg = std::unique_ptr<xapp::Config>( new xapp::Config( ) );
+       }
+
+       // must get a port from the config; no default
+       auto port = cfg->Get_port( "rmr-data" );
+       if( port.empty() ) {
+               fprintf( stderr, "<FAIL> no port in config file\n" );
+               exit( 1 );
+       }
+
+       // dig other data from the config
+       vlevel = cfg->Get_control_value( "verbose_level", 0 );
+       nthreads = cfg->Get_control_value( "thread_count", 1 );
+       // very simple flag processing (no bounds/error checking)
+
+       if( vlevel > 0 ) {
+               fprintf( stderr, "<XAPP> listening on port: %s\n", port.c_str() );
+               fprintf( stderr, "<XAPP> starting %d threads\n", nthreads );
+       }
+
+       // register the config change notification callback
+       cfg->Set_callback( config_cb, (void *) &vlevel );
+
+       x = new Xapp( port.c_str(), true );
+       x->Add_msg_cb( 1, cb1, x );             // register message callback
+
+       x->Run( nthreads );                             // let framework drive
+       // control should not return
+}