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Generic skills

The AEA generic buyer and seller skills demonstrate an interaction between two AEAs:

  • An AEA that provides a (data selling) service.
  • An AEA that demands this service.

Discussion

The scope of this guide is demonstrating how to create easily configurable AEAs. The buyer AEA finds the seller, negotiates the terms of trade, and if successful purchases the data by sending payment. The seller AEA sells the service specified in its skill.yaml file, delivering it to the buyer upon receiving payment.

Note that these agents do not utilize a smart contract but interact with a ledger to complete a transaction. Moreover, in this setup, the buyer agent has to trust the seller to send the data upon successful payment.

The corresponding packages can be customised to allow for a database or sensor to be defined from which data is loaded. This is done by first modifying the has_data_source variable in skill.yaml file of the generic_seller skill to True. Then you have to provide an implementation for the collect_from_data_source(self) method in the strategy.py file. More detailed instructions is beyond the scope of this guide.

Communication

The following diagram shows the communication between various entities in this interaction.

sequenceDiagram participant Search participant Buyer_AEA participant Seller_AEA participant Blockchain activate Buyer_AEA activate Search activate Seller_AEA activate Blockchain Seller_AEA->>Search: register_service Buyer_AEA->>Search: search_agents Search-->>Buyer_AEA: list_of_agents Buyer_AEA->>Seller_AEA: call_for_proposal Seller_AEA->>Buyer_AEA: propose Buyer_AEA->>Seller_AEA: accept Seller_AEA->>Buyer_AEA: match_accept Buyer_AEA->>Blockchain: transfer_funds Buyer_AEA->>Seller_AEA: send_transaction_hash Seller_AEA->>Blockchain: check_transaction_status Seller_AEA->>Buyer_AEA: send_data deactivate Buyer_AEA deactivate Search deactivate Seller_AEA deactivate Blockchain

Preparation instructions

Dependencies

Follow the Preliminaries and Installation sections from the AEA quick start.

Demo instructions

Create the seller AEA

First, fetch the seller AEA: 

aea fetch fetchai/generic_seller:0.29.0 --alias my_seller_aea
cd my_seller_aea
aea install
aea build

Alternatively, create from scratch.

The following steps create the seller from scratch: 

aea create my_seller_aea
cd my_seller_aea
aea add connection fetchai/p2p_libp2p:0.26.0
aea add connection fetchai/soef:0.27.0
aea add connection fetchai/ledger:0.20.0
aea add skill fetchai/generic_seller:0.28.0
aea config set --type dict agent.dependencies \
'{
  "aea-ledger-fetchai": {"version": "<2.0.0,>=1.0.0"}
}'
aea config set agent.default_connection fetchai/p2p_libp2p:0.26.0
aea config set --type dict agent.default_routing \
'{
  "fetchai/ledger_api:1.1.0": "fetchai/ledger:0.20.0",
  "fetchai/oef_search:1.1.0": "fetchai/soef:0.27.0"
}'
aea install
aea build

Create the buyer AEA

Then, in another terminal fetch the buyer AEA: 

aea fetch fetchai/generic_buyer:0.30.0 --alias my_buyer_aea
cd my_buyer_aea
aea install
aea build

Alternatively, create from scratch.

The following steps create the buyer from scratch: 

aea create my_buyer_aea
cd my_buyer_aea
aea add connection fetchai/p2p_libp2p:0.26.0
aea add connection fetchai/soef:0.27.0
aea add connection fetchai/ledger:0.20.0
aea add skill fetchai/generic_buyer:0.27.0
aea config set --type dict agent.dependencies \
'{
  "aea-ledger-fetchai": {"version": "<2.0.0,>=1.0.0"}
}'
aea config set agent.default_connection fetchai/p2p_libp2p:0.26.0
aea config set --type dict agent.default_routing \
'{
  "fetchai/ledger_api:1.1.0": "fetchai/ledger:0.20.0",
  "fetchai/oef_search:1.1.0": "fetchai/soef:0.27.0"
}'
aea install
aea build

Add keys for the seller AEA

Create the private key for the seller AEA based on the network you want to transact. To generate and add a private-public key pair for Fetch.ai Dorado use: 

aea generate-key fetchai
aea add-key fetchai fetchai_private_key.txt

Next, create a private key used to secure the AEA's communications: 

aea generate-key fetchai fetchai_connection_private_key.txt
aea add-key fetchai fetchai_connection_private_key.txt --connection

Finally, certify the key for use by the connections that request that: 

aea issue-certificates

Add keys and generate wealth for the buyer AEA

The buyer needs to have some wealth to purchase the data from the seller.

First, create the private key for the buyer AEA based on the network you want to transact. To generate and add a private-public key pair for Fetch.ai Dorado use: 

aea generate-key fetchai
aea add-key fetchai fetchai_private_key.txt

Then, create some wealth for your buyer based on the network you want to transact with. On the Fetch.ai Dorado network: 

aea generate-wealth fetchai

Next, create a private key used to secure the AEA's communications: 

aea generate-key fetchai fetchai_connection_private_key.txt
aea add-key fetchai fetchai_connection_private_key.txt --connection

Finally, certify the key for use by the connections that request that: 

aea issue-certificates

Update the skill configurations

The default skill configurations assume that the transaction is settled against the Fetch.ai ledger.

In the generic seller's skill configuration file (my_seller_aea/vendor/fetchai/skills/generi_seller/skill.yaml) the data_for_sale is the data the seller AEA is offering for sale. In the following case, this is a one item dictionary where key is generic and value is data.

Furthermore, the service_data is used to register the seller's service in the SOEF search node and make your agent discoverable. 

models:
  ...
  strategy:
    args:
      currency_id: FET
      data_for_sale:
        generic: data
      has_data_source: false
      is_ledger_tx: true
      ledger_id: fetchai
      location:
        latitude: 51.5194
        longitude: 0.127
      service_data:
        key: seller_service
        value: generic_service
      service_id: generic_service
      unit_price: 10
    class_name: GenericStrategy

The generic buyer skill configuration file (my_buyer_aea/vendor/fetchai/skills/generic_buyer/skill.yaml) includes the search_query which has to match the service_data of the seller.

models:
  ...
  strategy:
    args:
      currency_id: FET
      is_ledger_tx: true
      ledger_id: fetchai
      location:
        latitude: 51.5194
        longitude: 0.127
      max_negotiations: 1
      max_tx_fee: 1
      max_unit_price: 20
      search_query:
        constraint_type: ==
        search_key: seller_service
        search_value: generic_service
      search_radius: 5.0
      service_id: generic_service
    class_name: GenericStrategy

Update the skill configurations

Both skills are abstract skills, make them instantiable:

cd my_seller_aea
aea config set vendor.fetchai.skills.generic_seller.is_abstract false --type bool

cd my_buyer_aea
aea config set vendor.fetchai.skills.generic_buyer.is_abstract false --type bool

Run the AEAs

First, run the seller AEA:

aea run

Once you see a message of the form To join its network use multiaddr 'SOME_ADDRESS' take note of this address. (Alternatively, use aea get-multiaddress fetchai -c -i fetchai/p2p_libp2p:0.26.0 -u public_uri to retrieve the address.) This is the entry peer address for the local agent communication network created by the seller.

Then, configure the buyer to connect to this same local ACN by running the following command in the buyer terminal, replacing SOME_ADDRESS with the value you noted above: 

aea config set --type dict vendor.fetchai.connections.p2p_libp2p.config \
'{
  "delegate_uri": "127.0.0.1:11001",
  "entry_peers": ["SOME_ADDRESS"],
  "local_uri": "127.0.0.1:9001",
  "log_file": "libp2p_node.log",
  "public_uri": "127.0.0.1:9001"
}'

Then run the buyer AEA:

aea run

You will see that the AEAs negotiate and then transact using the Fetch.ai testnet.

Delete the AEAs

When you're done, stop the agents (CTRL+C), go up a level and delete the AEAs.

cd ..
aea delete my_seller_aea
aea delete my_buyer_aea
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