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Aggregation Skill

This demo shows how AEAs can aggregate values over the peer-to-peer network.


This demonstration shows how to set up a simple aggregation network in which several AEAs take an average of values fetched from different sources for the same real-world quantity. For this particular example, we take an average of Bitcoin prices from four public APIs.

Preparation Instructions


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


Create the AEAs

Repeat the following process four times in four different terminals (for each {i=0, i=1, i=2, i=3}):

Fetch the aggregator AEA:

aea fetch fetchai/simple_aggregator:0.5.5 --alias $agent_name
cd $agent_name
aea install
aea build
Alternatively, create from scratch:

Create the AEA:

aea create agent_name
cd agent_name
aea add connection fetchai/http_client:0.24.6
aea add connection fetchai/http_server:0.23.6
aea add connection fetchai/p2p_libp2p:0.27.5
aea add connection fetchai/soef:0.27.6
aea add connection fetchai/prometheus:0.9.6
aea add skill fetchai/advanced_data_request:0.7.6
aea add skill fetchai/simple_aggregation:0.3.6

aea config set agent.default_connection fetchai/p2p_libp2p:0.27.5
aea install
aea build

Set the desired decimal precision for the quantity:

aea config set --type int vendor.fetchai.skills.advanced_data_request.models.advanced_data_request_model.args.decimals 0

Disable the http server since it is not used in this demo:

aea config set --type bool vendor.fetchai.skills.advanced_data_request.models.advanced_data_request_model.args.use_http_server false

Set the cert requests for the peer-to-peer connection:

aea config set --type list vendor.fetchai.connections.p2p_libp2p.cert_requests \
'[{"identifier": "acn", "ledger_id": "fetchai", "not_after": "2023-01-01", "not_before": "2022-01-01", "public_key": "fetchai", "message_format": "{public_key}", "save_path": ".certs/conn_cert.txt"}]'

Match the agent index i to the COIN_URL and JSON_PATH below:

  • agg0: COIN_URL="" && JSON_PATH="data.amount"
  • agg1: COIN_URL="" && JSON_PATH="quotes.USD.price"
  • agg2: COIN_URL="" && JSON_PATH="result.price"
  • agg3: COIN_URL="" && JSON_PATH="bitcoin.usd"

Set the following configuration for the advanced_data_request skill:

aea config set vendor.fetchai.skills.advanced_data_request.models.advanced_data_request_model.args.url $COIN_URL
aea config set vendor.fetchai.skills.advanced_data_request.models.advanced_data_request_model.args.outputs '[{"name": "price", "json_path": '"\"$JSON_PATH\""'}]'

Set the name of the quantity to aggregate and choose an aggregation function for the AEAs (the currently implemented options are mean, median, and mode):

aea config set vendor.fetchai.skills.simple_aggregation.models.strategy.args.quantity_name price
aea config set vendor.fetchai.skills.simple_aggregation.models.strategy.args.aggregation_function mean

Specify a name for your aggregation service:

aea config set vendor.fetchai.skills.simple_aggregation.models.strategy.args.service_id $SERVICE_ID
aea config set vendor.fetchai.skills.simple_aggregation.models.strategy.args.search_query.search_value $SERVICE_ID

Additionally, create private keys for use with the ledger and the peer-to-peer connection:

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

Finally, certify the keys for use by the connections that request them:

aea issue-certificates

Configure the Peer-to-Peer Network

Set the multiaddress of the first AEA as an initial peer to help the remaining AEAs find each other on the network. Also, if these AEAs are all running on the same machine, set different ports for their connections to ensure there are no conflicts (from the agg1, agg2, and agg3 directories):

MULTIADDR=$(cd ../agg0 && aea get-multiaddress fetchai --connection)
aea config set --type dict vendor.fetchai.connections.p2p_libp2p.config \
"delegate_uri": "'$((11000+i))'",
"entry_peers": ["/dns4/'"$MULTIADDR\""'],
"local_uri": "'$((9000+i))'",
"log_file": "libp2p_node.log",
"public_uri": "'$((9000+i))'"
aea config set vendor.fetchai.connections.prometheus.config.port $((20000+i))
aea config set vendor.fetchai.connections.http_server.config.port $((8000+i))

Oracle Integration (optional)

To publish the aggregated value to an oracle smart contract, add the ledger connection and simple oracle skill to one of the aggregators:

aea add connection fetchai/ledger:0.21.5
aea add skill fetchai/simple_oracle:0.16.5

Configure the simple oracle skill for the fetchai ledger:

aea config set vendor.fetchai.skills.simple_oracle.models.strategy.args.ledger_id fetchai
aea config set vendor.fetchai.skills.simple_oracle.models.strategy.args.update_function update_oracle_value

Generate some wealth to use for transactions on the testnet ledger:

aea generate-wealth fetchai

Set the name of the oracle value to match the value collected by the aggregators:

aea config set vendor.fetchai.skills.simple_oracle.models.strategy.args.oracle_value_name price_mean

Run the AEAs

Run each of the aggregator AEAs in separate terminals:

aea run

After a few moments, you should see the AEAs finding peers, making observations, sending them to peers, and taking the average of their observations:

info: [agg_i] found agents...
info: [agg_i] Fetching data from...
info: [agg_i] Observation: {'price': {'value':...
info: [agg_i] sending observation to peer...
info: [agg_i] received observation from sender...
info: [agg_i] Observations:...
info: [agg_i] Aggregation (mean):...