Distributed Price Feed

Distributed Price Feed spawns a number of libp2p nodes that form a distributed system. Each node pulls ETH price from an external provider, communicates it to the other nodes and once certain conditions are met they all persist this value in a shared postgres instances.

Dependencies

github.com/libp2p/go-libp2p - to setup and run nodes github.com/libp2p/go-libp2p-kad-dht - implementation of Kademlia DHT. For nodes discovery github.com/libp2p/go-libp2p-pubsub - pubsub implementation for libp2p. So that nodes are able to gossip with each other github.com/multiformats/go-multiaddr - implementation of Multiaddr address format. To connect to bootstrap peer github.com/lib/pq - postgres database driver github.com/jmoiron/sqlx - nice extensions to standard sql library github.com/shopspring/decimal - to make sure no precision is lost in decimal numbers go.uber.org/zap - logging

Requiremenets

• docker
• kubernetes

Usage

I used kind to run local cluster. If you choose to use another tool, simply run the docker build command from the ./scripts/package.sh file in order to build docker image. Then load it to your local cluster. Otherwise you may use the helper script below.

To build docker image and add it to kind local cluster:

./scripts/package.sh

To deploy the network with 4 nodes: Note: bootstrap node is always deployed. The number here relates to the number of additional nodes to be deployed so in total it's 1 + NODES.

NODES=4
./scripts/deploy.sh

To stop the system:

./scripts/clean-deployments.sh

Monitoring

To check if the pods are running:

kubectl get pods

To check logs of a pod:

kubectl logs {{pod_name}}

To check the eth prices added to the database:

kubectl exec -it {{postgres_pod}} -- psql -d postgres -U postgres

then:

select * from eth_prices order by createdat desc;