If you want to create Autonomous Economic Agents (AEAs) that can act independently of constant user input and autonomously execute actions to achieve their objective, you can use the Fetch.ai AEA framework.

This example will take you through the simplest AEA in order to make you familiar with the framework.

Preliminaries

Create and enter into a new working directory.

mkdir my_aea_projects/
cd my_aea_projects/

We highly recommend using a virtual environment to ensure consistency across dependencies.

Check that you have pipenv.

which pipenv

If you don't have it, install it. Instructions are here.

Once installed, create a new environment and open it (here we use Python 3.7 but the AEA framework supports any Python >= 3.6).

touch Pipfile && pipenv --python 3.7 && pipenv shell

Installing docker

Note

For the purpose of the quickstart only, you can skip installation of docker.

At some point, you will need Docker installed on your machine (e.g. to run an OEF search and communication node).

Download the scripts and examples directories

Note

For the purpose of the quickstart only, you can skip downloading the scripts and examples directories.

Download folders containing examples and scripts:

svn export https://github.com/fetchai/agents-aea.git/trunk/examples
svn export https://github.com/fetchai/agents-aea.git/trunk/scripts

You can install the svn command with (brew install subversion or sudo apt-get install subversion).

Installation

The following installs the entire AEA package which also includes a command-line interface (CLI).

pip install aea[all]

If you are using zsh rather than bash type

pip install 'aea[all]'

Known issues

If the installation steps fail, it might be a dependency issue.

The following hints can help:

• Ubuntu/Debian systems only: install Python 3.7 headers.

  sudo apt-get install python3.7-dev
  

• Windows users: install tools for Visual Studio.

Setup Author name

You can now setup your author name:

aea init

This is your unique author name in the Fetch.ai ecosystem.

You should see a similar output (with your input replacing the sample input):

Do you have a Registry account? [y/N]: n
Create a new account on the Registry now:
Username: fetchai
Email: [email protected]
Password:
Please make sure that passwords are equal.
Confirm password:
    _     _____     _    
   / \   | ____|   / \   
  / _ \  |  _|    / _ \  
 / ___ \ | |___  / ___ \ 
/_/   \_\|_____|/_/   \_\

v0.3.3

AEA configurations successfully initialized: {'author': 'fetchai'}

Note

If you would rather not create an account on the registry at this point, then run `aea init --local` instead.

Echo skill demo

The echo skill is a simple demo that introduces you to the main business logic components of an AEA. The fastest way to create your first AEA is to fetch it!

If you want to follow a step by step guide we show you how to do it at the end of the file.

aea fetch fetchai/my_first_aea:0.4.0
cd my_first_aea

To learn more about the folder structure of an AEA project read on here.

Usage of the stub connection

AEAs use envelopes containing messages for communication. We use a stub connection to send envelopes to and receive envelopes from the AEA.

The stub connection is already added to the AEA by default.

A stub connection provides an I/O reader and writer. It uses two files for communication: one for incoming envelopes and the other for outgoing envelopes.

The AEA waits for a new envelope posted to the file my_first_aea/input_file, and adds a response to the file my_first_aea/output_file.

The format of each envelope is the following:

TO,SENDER,PROTOCOL_ID,ENCODED_MESSAGE,

For example:

recipient_aea,sender_aea,fetchai/default:0.1.0,\x08\x01*\x07\n\x05hello,

Run the AEA

Run the AEA with the default fetchai/stub:0.4.0 connection.

aea run

or

aea run --connections fetchai/stub:0.4.0

You will see the echo skill running in the terminal window.

    _     _____     _    
   / \   | ____|   / \   
  / _ \  |  _|    / _ \  
 / ___ \ | |___  / ___ \ 
/_/   \_\|_____|/_/   \_\

v0.3.3

Starting AEA 'my_first_aea' in 'async' mode ...
info: Echo Handler: setup method called.
info: Echo Behaviour: setup method called.
info: [my_first_aea]: Start processing messages...
info: Echo Behaviour: act method called.
info: Echo Behaviour: act method called.
info: Echo Behaviour: act method called.
...

The framework first calls the setup method on the Handler, and Behaviour code in that order; after which it repeatedly calls the Behaviour method act. This is the main agent loop in action.

Let's look at the Handler in more depth.

Add a message to the input file

From a different terminal and same directory, we send the AEA a message wrapped in an envelope via the input file.

echo 'my_first_aea,sender_aea,fetchai/default:0.1.0,\x08\x01*\x07\n\x05hello,' >> input_file

You will see the Echo Handler dealing with the envelope and responding with the same message to the output_file, and also decoding the Base64 encrypted message in this case.

info: Echo Behaviour: act method called.
info: Echo Handler: message=Message(dialogue_reference=('', '') message_id=1 target=0 performative=bytes content=b'hello'), sender=sender_aea
info: Echo Behaviour: act method called.
info: Echo Behaviour: act method called.

Stop the AEA

Stop the AEA by pressing CTRL C

You should see the AEA being interrupted and then calling the teardown() methods:

info: Echo Behaviour: act method called.
info: Echo Behaviour: act method called.
^C my_first_aea interrupted!
my_first_aea stopping ...
info: Echo Handler: teardown method called.
info: Echo Behaviour: teardown method called.

Write a test for the AEA

We can write an end-to-end test for the AEA utilising helper classes provided by the framework.

Step by step install

The following test class replicates the preceding demo and tests it's correct behaviour. The `AEATestCase` classes are a tool for AEA developers to write useful end-to-end tests of their AEAs.

import signal
import time

from aea.mail.base import Envelope
from aea.protocols.default.message import DefaultMessage
from aea.protocols.default.serialization import DefaultSerializer
from aea.test_tools.test_cases import AEATestCase


class TestEchoSkill(AEATestCase):
    """Test that echo skill works."""

    def test_echo(self):
        """Run the echo skill sequence."""
        process = self.run_agent()
        is_running = self.is_running(process)
        assert is_running, "AEA not running within timeout!"

        # add sending and receiving envelope from input/output files
        message_content = b"hello"
        message = DefaultMessage(
            performative=DefaultMessage.Performative.BYTES, content=message_content,
        )
        sent_envelope = Envelope(
            to=self.agent_name,
            sender="sender_aea",
            protocol_id=message.protocol_id,
            message=DefaultSerializer().encode(message),
        )

        self.send_envelope_to_agent(sent_envelope, self.agent_name)

        time.sleep(2.0)
        received_envelope = self.read_envelope_from_agent(self.agent_name)

        assert sent_envelope.to == received_envelope.sender
        assert sent_envelope.sender == received_envelope.to
        assert sent_envelope.protocol_id == received_envelope.protocol_id
        assert sent_envelope.message == received_envelope.message

        check_strings = (
            "Echo Handler: setup method called.",
            "Echo Behaviour: setup method called.",
            "Echo Behaviour: act method called.",
            "content={}".format(message_content),
        )
        missing_strings = self.missing_from_output(process, check_strings)
        assert (
            missing_strings == []
        ), "Strings {} didn't appear in agent output.".format(missing_strings)

        assert (
            self.is_successfully_terminated()
        ), "Echo agent wasn't successfully terminated."

Place the above code into a file `test.py` in your AEA project directory (the same level as the `aea-config.yaml` file). To run, execute the following:

pytest test.py

Delete the AEA

Delete the AEA from the parent directory (cd .. to go to the parent directory).

aea delete my_first_aea

Next steps

For more detailed analysis of the core components of the framework, please check the following:

• Core components

We recommend you learn more about the protocols agents use to communicate with each other. Understanding protocols is core to developing your own agent. Check out the following:

• Protocols

We also recommend you have a look at skill development. Skills are the core business logic commponents of an AEA. Check out the following:

• Skills

For more demos, use cases or step by step guides, please check the following:

• Generic skill use case
• Weather skill demo
• Thermometer step by step guide

Step by step install

Create a new AEA
First, create a new AEA project and enter it.

aea create my_first_aea
cd my_first_aea

Add the echo skill
Second, add the echo skill to the project.

aea add skill fetchai/echo:0.1.0        

This copies the `fetchai/echo:0.1.0` skill code containing the "behaviours", and "handlers" into the project, ready to run. The identifier of the skill `fetchai/echo:0.1.0` consists of the name of the author of the skill, followed by the skill name and its version.

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Ways To Build An Aea Next:
Aea And Web Frameworks