watcher-ts/packages/codegen

Code Generator

Setup

• In root of the repository:

  • Install required packages:

    yarn
    

  • Build files:

    yarn build
    

Run

• Create a .yaml config file in the following format for generating a watcher:

  # Example config.yaml
  # Contracts to watch (required).
  # Can pass empty array ([]) when using subgraphPath.
  contracts:
      # Contract name.
    - name: Example
      # Contract file path or an url.
      path: ../graph-node/test/contracts/Example.sol
      # Contract kind (should match that in {subgraphPath}/subgraph.yaml if subgraphPath provided)
      kind: Example1
  
  # Output folder path (logs output using `stdout` if not provided).
  outputFolder: ../test-watcher
  
  # Code generation mode [eth_call | storage | all | none] (default: none).
  mode: none
  
  # Kind of watcher [lazy | active] (default: active).
  kind: active
  
  # Watcher server port (default: 3008).
  port: 3008
  
  # Flatten the input contract file(s) [true | false] (default: true).
  flatten: true
  
  # Path to the subgraph build (optional).
  # Can set empty contracts array when using subgraphPath.
  subgraphPath: ../graph-node/test/subgraph/example1/build
  
  # NOTE: When passed an *URL* as contract path, it is assumed that it points to an already flattened contract file.
  

• Run the following command to generate a watcher from contract(s):

  yarn codegen --config-file <config-file-path>
  

  • config-file(alias: c): Watcher generation config file path (yaml) (required).

  Example:

  • Generate code using a config file config.yaml:

    yarn codegen --config-file ./config.yaml
    

  This will create a folder containing the generated code at the path provided in config. Follow the steps in Run Generated Watcher to setup and run the generated watcher.

Run Generated Watcher

Setup

• Run the following command to install required packages:

  yarn
  

• In the config file (environments/local.toml):

  • Update the state checkpoint settings.

• Create the databases configured in environments/local.toml.

Customize

• Indexing on an event:

  • Edit the custom hook function handleEvent (triggered on an event) in src/hooks.ts to perform corresponding indexing using the Indexer object.

  • While using the indexer storage methods for indexing, pass diff as true if default state is desired to be generated using the state variables being indexed.

• Generating state:

  • Edit the custom hook function createInitialState (triggered if the watcher passes the start block, checkpoint: true) in src/hooks.ts to save an initial State using the Indexer object.

  • Edit the custom hook function createStateDiff (triggered on a block) in src/hooks.ts to save the state in a diff State using the Indexer object. The default state (if exists) is updated.

  • Edit the custom hook function createStateCheckpoint (triggered just before default and CLI checkpoint) in src/hooks.ts to save the state in a checkpoint State using the Indexer object.

Run

• Run lint:

  yarn lint
  

• Run the watcher:

  yarn server
  

• If the watcher is an active watcher:

  • Run the job-runner:

    yarn job-runner
    

  • To watch a contract:

    yarn watch:contract --address <contract-address> --kind <contract-kind> --checkpoint <true | false> --starting-block [block-number]
    

  • To fill a block range:

    yarn fill --start-block <from-block> --end-block <to-block>
    

  • To create a checkpoint for a contract:

    yarn checkpoint --address <contract-address> --block-hash [block-hash]
    

  • To reset the watcher to a previous block number:

    • Reset state:

      yarn reset state --block-number <previous-block-number>
      

    • Reset job-queue:

      yarn reset job-queue --block-number <previous-block-number>
      

  • To export the watcher state:

    yarn export-state --export-file [export-file-path]
    

  • To import the watcher state:

    yarn import-state --import-file <import-file-path>
    

  • To inspect a CID:

    yarn inspect-cid --cid <cid>
    

Known Issues

• Currently, node-fetch v2.6.2 is being used to fetch from URLs as v3.0.0 is an ESM-only module and ts-node transpiles to import it using require.