ConsumerTask

In this task, we will consume the temperature value produced in the producer task. We will first create a consume task. For this, execute the following command

DH> python programs/scripts/dune-create-task.py . DuneAuthor Tutorials/TempConsume

This will create TempConsume task. To use the temperature value produced by the producer task we need first to bind the message from IMC and write a consume method.

First binding the value from the IMC message, for this include bind<IMC::Temperature>(this); in the constructor.

Task(const std::string& name, Tasks::Context& ctx):
  DUNE::Tasks::Task(name, ctx)
{
  bind<IMC::Temperature>(this);
}

Then create a consumer method before the main loop. The following is the consumer method

 void
  consume(const IMC::Temperature* msg)
  {
    inf("temperature is %f", msg->value);
  }

Compiling the consumer task

In order to compile the consumer task, follow the instructions of the producer task.

cd DBuild>
DBuild>$ make rebuild_cache
DBuild>$ make

This will compile the consumer task.

Testing the consumer task

Create consumer.ini file in DH>/etc/development folder. In this folder include the contents as given below

[Include ../common/transports.ini]

[Tutorials.TempConsume]
Enabled = Always
Entity Label = Consumer

[Transports.Logging]
Enabled = Always
Entity Label = Logger
Transports = Temperature

The first line [Include ..] includes the transports.ini file into the current file. [Tutorials.TempConsume] directs the task towards the TempConsume directory. Enabled = Always tells that the task is always enabled. Entity Label = Consumer informs that this task is a consumer. For the entity label there is no need provide in the Task.cpp file, rather dune takes care of the entity label.

Then run the command

DBuild>$ ./dune -c ../etc/development/Tutorials/consumer

Upon execution you can see the output as:

[2013/05/31 17:57:10] - MSG [Transports.Logging] >> starting
[2013/05/31 17:57:10] - MSG [Tutorials.TempConsume] >> starting
[2013/05/31 17:57:10] - MSG [Transports.Logging] >> log started '20130531/175710_idle'

We can see that the tasks Tutorials.TempConsumer and Transports.Logging have started.