Agents Name Service

Introduction

This file can be run on any platform supporting Python, with the necessary install permissions. This example shows how to set up the Agents Name Service contract using the uagents and cosmpy Python libraries. The Fetch.ai Name Service Smart Contract aims at enhancing the usability and accessibility of the Fetch.ai blockchain by providing a decentralized, secure, and user-friendly way to manage names for various digital entities. Indeed, the Name Service Smart Contract acts similarly to a phonebook for the Fetch.ai blockchain; It assigns memorable names (i.e., domains) to blockchain addresses, making it easier to find and interact with other agents and resources on the network. Imagine it as a way to give user-friendly names to complex wallet addresses.

In this guide we set up a communication line between two agents, Alice and Bob, where Alice sends a message to Bob every 5 seconds by first constructing Bob's address using a predefined domain (example.agent) and Bob's name (bob-0).

In turn, Bob is coded to listen for incoming messages and log them. On startup, Bob registers its name on a blockchain network using a name service contract. This ensures that Alice can address messages to Bob correctly.

Let's get started!

Walk-through

First of all, we need to create 2 Python scripts for our two agents using the following commands within your terminal:

Bob:

windows
echo. > bob.py

Alice:

windows
echo. > alice.py

Bob

Let's start with the first agent of this example, Bob.

First of all, we import the required libraries and modules:

bob.py
 
from cosmpy.aerial.wallet import LocalWallet
from uagents import Agent, Context, Model
from uagents.network import get_faucet, get_name_service_contract

LocalWallet: From the cosmpy.aerial.wallet module, this is used to create and manage wallets for blockchain interactions.
Agent, Context, Model: From the uagents module, these are used to define the agent, its context, and the message model.
get_faucet: From the uagents.network module, this function is used to get a faucet for funding wallets.
get_name_service_contract: From the uagents.network module, this function is used to get the contract for registering agent names on the network.

We then define the Message model defining the structure of messages that Bob will be able to handle:

bob.py
 
class Message(Model):
    message: str

We have defined a Message data model which contains a single attribute message of type string.

We then need to initialize the agent:

bob.py
 
bob = Agent(
    name="bob-0",
    seed="agent bob-0 secret phrase",
    port=8001,
    endpoint=["http://localhost:8001/submit"],
)

We have created an agent named bob-0 with a specified seed. The agent listens on port 8001 and has an endpoint for receiving messages.

We are now ready to set up the Wallet, Name Service Contract, and Faucet:

bob.py
 
my_wallet = LocalWallet.from_unsafe_seed("registration test wallet")
name_service_contract = get_name_service_contract(test=True)
faucet = get_faucet()
 
DOMAIN = "example.agent"
 
faucet.get_wealth(my_wallet.address())

We first create a wallet from a seed phrase and this wallet is used for interacting with the Fetch.ai blockchain. We then proceed and define the Name Service Contract. It retrieves the name service contract to register the agent's name on the blockchain. The test=True parameter indicates this is a test setup. Then, we define the faucet used to fund the wallet with test tokens. We then define the domain for the agent's name registration and finally proceed to request funds from the faucet to ensure the agent's wallet has sufficient funds to operate. Remember that you need to provide the name, seed, port, endpoint and DOMAIN parameters to correctly run this code!

We continue and define Bob's functions. We start with a register_agent_name function which registers Bob's name within the blockchain using the agent's wallet, address, name and domain parameters:

bob.py
 
@bob.on_event("startup")
async def register_agent_name(ctx: Context):
    await name_service_contract.register(
        bob.ledger, my_wallet, bob.address, bob.name, DOMAIN
    )

Here, we defined the register_agent_name function. It registers the agent's name on the blockchain when the agent is initialized. The function uses the name service contract to register bob-0.example.agent agent using the my_wallet wallet. It is important that you provide only lower case letters for your agent's name and DOMAIN parameters as otherwise you will face issues the moment you run your agent.

We now define a message_handler function for Bob to handle incoming messages:

bob.py
 
@bob.on_message(model=Message)
async def message_handler(ctx: Context, sender: str, msg: Message):
    ctx.logger.info(f"Received message from {sender}: {msg.message}")
 
 
if __name__ == "__main__":
    bob.run()

Here we defined a function handling incoming messages of type Message. It logs the sender's address and the message content.

Finally, we save and run the script.

The overall script for this example should look as follows:

bob.py
 
from cosmpy.aerial.wallet import LocalWallet
from uagents import Agent, Context, Model
from uagents.network import get_faucet, get_name_service_contract
 
 
# NOTE: Run sender_agent.py before running receiver_agent.py
 
 
class Message(Model):
    message: str
 
 
bob = Agent(
    name="bob-0",
    seed="agent bob-0 secret phrase",
    port=8001,
    endpoint=["http://localhost:8001/submit"],
)
 
my_wallet = LocalWallet.from_unsafe_seed("registration test wallet")
name_service_contract = get_name_service_contract(test=True)
faucet = get_faucet()
 
DOMAIN = "example.agent"
 
faucet.get_wealth(my_wallet.address())
 
 
@bob.on_event("startup")
async def register_agent_name(ctx: Context):
    await name_service_contract.register(
        bob.ledger, my_wallet, bob.address, bob.name, DOMAIN
    )
 
 
@bob.on_message(model=Message)
async def message_handler(ctx: Context, sender: str, msg: Message):
    ctx.logger.info(f"Received message from {sender}: {msg.message}")
 
 
if __name__ == "__main__":
    bob.run()

Alice

Let's now define the code for our second agent, Alice.

First of all, we import the required libraries and modules:

alice.py
 
from uagents import Agent, Context, Model

Let's then define the message data model similarly to what we did for Bob:

alice.py
 
class Message(Model):
    message: str

We proceed and initialize the agent:

alice.py
 
alice = Agent(
    name="alice-0",
    seed="agent alice-0 secret phrase",
    port=8000,
    endpoint=["http://localhost:8000/submit"],
)

We initialize an agent named alice-0 with a specified seed. The agent listens on port 8000 and has an endpoint for submitting messages.

We then need to define the domain of the agent. The DOMAIN specifies the domain for the agent communication. This domain is used to construct the full address of Bob:

alice.py
 
    message: str
 
 
alice = Agent(
    name="alice-0",
    seed="agent alice-0 secret phrase",
    port=8000,
    endpoint=["http://localhost:8000/submit"],
)
 
DOMAIN = "example.agent"

Finally, we define the functions and behaviours for Alice:

alice.py
 
@alice.on_interval(period=5)
async def alice_interval_handler(ctx: Context):
    bob_name = "bob-0" + "." + DOMAIN
    ctx.logger.info(f"Sending message to {bob_name}...")
    await ctx.send(bob_name, Message(message="Hello there bob."))
 
 
if __name__ == "__main__":
    alice.run()

This alice_interval_handler() function runs at regular intervals of 5 seconds to send messages. The handler constructs Bob's address using the domain and sends a message to Bob. It combines bob-0 name with the DOMAIN to form bob-0.example.agent. The agent logs the action and sends a message with the content "Hello there bob." to Bob agent.

Remember that you need to provide the name, seed, port, endpoint and DOMAIN parameters to correctly run this code! Additionally, it is important that you provide only lower case letters for your agent's name and DOMAIN parameters as otherwise you will face issues the moment you run your agent.

The overall script for this example should look as follows:

alice.py
 
from uagents import Agent, Context, Model
 
 
class Message(Model):
    message: str
 
 
alice = Agent(
    name="alice-0",
    seed="agent alice-0 secret phrase",
    port=8000,
    endpoint=["http://localhost:8000/submit"],
)
 
DOMAIN = "example.agent"
 
 
@alice.on_interval(period=5)
async def alice_interval_handler(ctx: Context):
    bob_name = "bob-0" + "." + DOMAIN
    ctx.logger.info(f"Sending message to {bob_name}...")
    await ctx.send(bob_name, Message(message="Hello there bob."))
 
 
if __name__ == "__main__":
    alice.run()

Expected output

Within your terminal windows you should see something similar to the following:

Bob:


INFO:     [bob-0]: Registering on almanac contract...
INFO:     [bob-0]: Registering on almanac contract...complete
INFO:     [network]: Registering name...
INFO:     [network]: Registering name...complete
INFO:     [bob-0]: Starting server on http://0.0.0.0:8001 (Press CTRL+C to quit)
INFO:     [bob-0]: Received message from agent1qwquu2d237gntfugrnwch38g8jkl76vdr05qjm4wyps6ap04fvt8vtzhpqw: Hello there bob.
INFO:     [bob-0]: Received message from agent1qwquu2d237gntfugrnwch38g8jkl76vdr05qjm4wyps6ap04fvt8vtzhpqw: Hello there bob.
INFO:     [bob-0]: Received message from agent1qwquu2d237gntfugrnwch38g8jkl76vdr05qjm4wyps6ap04fvt8vtzhpqw: Hello there bob.
INFO:     [bob-0]: Received message from agent1qwquu2d237gntfugrnwch38g8jkl76vdr05qjm4wyps6ap04fvt8vtzhpqw: Hello there bob.

Alice:


INFO:     [alice-0]: Registering on almanac contract...
INFO:     [alice-0]: Registering on almanac contract...complete
INFO:     [alice-0]: Sending message to bob-0.agent...
INFO:     [alice-0]: Starting server on http://0.0.0.0:8000 (Press CTRL+C to quit)
INFO:     [alice-0]: Sending message to bob-0.agent...
INFO:     [alice-0]: Sending message to bob-0.agent...
INFO:     [alice-0]: Sending message to bob-0.agent...

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