/graph-node-UP

Primary LanguageTypeScriptMIT LicenseMIT

The Graph

Extract event information from ERC725 Account using The Graph

Getting Started

Read Investigation.md file in the docs folder to have more information on The Graph.

Installation

yarn install

Run a graph node locally

docker-compose up

This will start IPFS, Postgres and Graph Node in Docker and create persistent data directories for IPFS and Postgres in ./data/ipfs and ./data/postgres. You can access these via:

  • Graph Node:
    • GraphiQL: http://localhost:8000/
    • HTTP: http://localhost:8000/subgraphs/name/<subgraph-name>
    • WebSockets: ws://localhost:8001/subgraphs/name/<subgraph-name>
    • Admin: http://localhost:8020/
  • IPFS:
    • 127.0.0.1:5001 or /ip4/127.0.0.1/tcp/5001
  • Postgres:
    • postgresql://graph-node:let-me-in@localhost:5432/graph-node

The logs will show the current block head. You can compare it with what’s in the block explorer. The subgraph is running locally and is connected to the correct blockchain. CurrentBlock

Deploy a subgraph to the running Graph Node

This command will generate a folder generated which files are used in src/mapping.ts.

yarn codegen
yarn create-local

yarn deploy-local

Note : yarn deploy-local command might ask you to run the following command.

graph create --node http://127.0.0.1:8020 example

Understand the purpose of each file

File subgraph.yaml (the subgraph manifest) specifies information on the Smart Contract we are indexing, the events that are emitted by the smart contract and the network we are connecting to.

File schema.graphql specifies the entities we store in the subgraph.

File mapping.ts specifies the functions to run when a specific event is emitted. The functions store the pieces of information we want in the database of the suibgraph.

Example

  1. An event DataChanged is emitted by the smart contract 0x41D0ADD4e04fd73598244cab0090E7D8042597f9.

  2. The function handleUpdatedUP is triggered. The parameter is dataKey and dataValue. dataValue could be use to decode the data but we are using erc725js library instead. We use fetchData function from erc725js library to decode data send by the emitted event. Then, handleUpdated checkes if a data entity with the id dataKey already exists. If not, it creates a new entity Data, if yes, it updates it. Finally, the function saves the entity.

Improvement

  • Add the profileImage in the Data entity (file schema.graphql).

Connect to pgadmin to visualise data

  • Create a new server on pgadmin
  • Connect to the database
POSTGRES_USER: graph-node
POSTGRES_PASSWORD: let-me-in
POSTGRES_DB: graph-node
PGDATA: "/data/postgres"

Blocker

(26.10.2022)

  1. The Graph is not supporting external libraries like web3 or erc725js yet. In mapping.ts we use the libraries to extract information of ERC725 account. Without these libraries we can t decode the event emitted by the smart contract. importlibraries
  1. A subgraph can listen to one smart contract. In our case, it means we would have one subgraph for each universal profile which is not relevant.

Helpers

  • If issue when connecting the subgraph to the graph node : display the logs of the container
docker logs --follow CONTAINER
  • If issue when running yarn create-local: build step by step the mapping.ts file to understand where the issue comes from and try yarn build at each step.

Resources :