watcher-ts/packages/graph-test-watcher/README.md

# Example Watcher

## Setup

* Run the following command to install required packages:

  ```bash
  yarn
  ```

* Create a postgres12 database for the watcher:

  ```bash
  sudo su - postgres
  createdb graph-test-watcher
  ```

* If the watcher is an `active` watcher:

  Create database for the job queue and enable the `pgcrypto` extension on them (https://github.com/timgit/pg-boss/blob/master/docs/usage.md#intro):

  ```
  createdb graph-test-watcher-job-queue
  ```

  ```
  postgres@tesla:~$ psql -U postgres -h localhost graph-test-watcher-job-queue
  Password for user postgres:
  psql (12.7 (Ubuntu 12.7-1.pgdg18.04+1))
  SSL connection (protocol: TLSv1.3, cipher: TLS_AES_256_GCM_SHA384, bits: 256, compression: off)
  Type "help" for help.

  graph-test-watcher-job-queue=# CREATE EXTENSION pgcrypto;
  CREATE EXTENSION
  graph-test-watcher-job-queue=# exit
  ```

* Update the [config](./environments/local.toml) with database connection settings.

* Update the `upstream` config in the [config file](./environments/local.toml) and provide the `ipld-eth-server` GQL API and the `indexer-db` postgraphile endpoints.

## Customize

* Indexing on an event:

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

  * Refer to [hooks.example.ts](./src/hooks.example.ts) for an example hook function for events in an ERC20 contract.

## Run

* Run the watcher:

  ```bash
  yarn server
  ```

GQL console: http://localhost:3008/graphql

* If the watcher is an `active` watcher:

  * Run the job-runner:

    ```bash
    yarn job-runner
    ```

  * To watch a contract:

    ```bash
    yarn watch:contract --address <contract-address> --kind Example --starting-block [block-number]
    ```

  * To fill a block range:

    ```bash
    yarn fill --startBlock <from-block> --endBlock <to-block>
    ```