SubQuery - Starter Package

The Starter Package is an example that you can use as a starting point for developing your SubQuery project. A SubQuery package defines which data The SubQuery will index from the substrate network, and how it will store it.

##Preparation

Install the SubQuery CLI

Install SubQuery CLI globally on your terminal by using Yarn or NPM:

$npm install -g @subql-cli
$yarn global add @subql-cli

Run help to see available commands and usage provide by CLI

$suqbl help

Initialize the starter package

Inside the directory in which you want to create the SubQuery project, simply replace project-name with your project name and run the command:

$subql init --starter project-name

Then you should see a folder with your project name has been created inside the directory, you can use this as the start point of your project. And the files should be identical as following:

- project-name
  L package.json
  L project.yaml
  L README.md
  L schema.graphql
  L tsconfig.json
  L docker-compose.yml
  L src
    L index.ts
    L mappings
      L mappingHandlers.ts

Last, under the project directory, run following command to install all the dependency.

$yarn install

Configure your project

The Manifest

• The project.yaml is an entry point of your project. It defined the endpoint of the blockchain to be indexed. dataSources.kind defines the type of datasources. In mapping.handlers, we currently support three types of handlers, also EventHandler and CallHandler support filters.

The GraphQL Schema

• Next, you need to define the GraphQL schemas inside of schema.graphql file. To know how to write in "GraphQL schema language", we recommend to check out on Schemas and Types.

Mapping function

The mappings function defined how to transform the indexed data into the entities have defined in the schema above. Mappings are written in a subset of TypeScript called AssemblyScript which can be compiled to WASM (WebAssembly).

• We also provided a few examples of a mapping function in src/mappings/mappingHandlers.ts. For each handler that is defined in project.yaml under mapping.handlers, create an exported function of the same name.

• Also, under the src/index.ts, you have to export the functions of handlers has defined in above.

Code generation

Next, run codegen command under your project root directory.

$yarn codegen

• This will create a new directory src/types which contains all generate entities in AssemblyScript.
• Generate entity class for each type you have defined previously in schema.graphql. These classes provide type-safe entity loading, read and write access to entity fields.

Index a SubQuery project

Build the project

In order to index your subquery project, it is mandatory to build your project first. Run this command under the project directory.

$yarn build

Run required systems in docker

Then, under the project directory run following command:

$docker-compose up

Query the project

With the SubQuery project above deployed successfully, now in your docker container should have subql-node,Postgres and Hasura/graphql-engine running.

Open your browser and head to http://localhost:8080/console.

Under the DATA tab, on the left top corner select the schema you just created, it usually named public. Then you can see the table is currently untracked, click on the Track button.

Finally, head to the GRAPHQL tab, in the explorer you should see the table is ready to query.

##Redeploy a project

If any changes to your SubQuery project require SubQuery node to reindex, it is necessary to repeat the above steps in Configure your project. And reindex again starting with the genesis block. Also, restore a clean schema will ensure data stored correctly, go to Hasura console and under the DATA tab, select the corresponding schema and remove it.