Schema linting in GraphQL - Mini Project: Build & Apply

GraphQL Schema Linting

📖 Scenario: You are working on a GraphQL API for a book store. You want to make sure your schema is clean and follows good practices before sharing it with your team.

🎯 Goal: Build a simple GraphQL schema and add linting rules to check for common issues like missing descriptions and consistent naming.

📋 What You'll Learn

Create a GraphQL schema with types for Book and Author

Add a configuration variable to enable linting rules

Write a linting function that checks for missing descriptions on types and fields

Complete the linting setup to output linting results for the schema

💡 Why This Matters

🌍 Real World

GraphQL schema linting helps teams maintain clean, consistent API definitions that are easier to understand and maintain.

💼 Career

Many companies use GraphQL for APIs; knowing how to write and lint schemas is valuable for backend and full-stack developers.

1

Create the GraphQL schema

Create a GraphQL schema string called schema with these exact types: Book with fields id: ID!, title: String!, and author: Author!; and Author with fields id: ID! and name: String!.

GraphQL

# Your code here

Need a hint?

Define the schema as a multiline string with the exact types and fields.

2

Add linting configuration

Create a variable called linting_enabled and set it to True to enable linting.

GraphQL

schema = """
type Book {
  id: ID!
  title: String!
  author: Author!
}

type Author {
  id: ID!
  name: String!
}
"""

# Your code here

Need a hint?

Just create a boolean variable named linting_enabled and set it to True.

3

Write linting function

Write a function called lint_schema that takes schema as input and returns a list called issues. The function should check if the schema string contains the word "description". If not, add the string "Missing descriptions in schema" to issues. Return issues.

GraphQL

schema = """
type Book {
  id: ID!
  title: String!
  author: Author!
}

type Author {
  id: ID!
  name: String!
}
"""

linting_enabled = True

def lint_schema(schema):
    # Your code here

Need a hint?

Check if the word description is missing in the schema string and add a message to the list.

4

Complete linting setup

Add code that checks if linting_enabled is True. If yes, call lint_schema(schema) and store the result in a variable called lint_results.

GraphQL

schema = """
type Book {
  id: ID!
  title: String!
  author: Author!
}

type Author {
  id: ID!
  name: String!
}
"""

linting_enabled = True

def lint_schema(schema):
    issues = []
    if "description" not in schema:
        issues.append("Missing descriptions in schema")
    return issues

if linting_enabled:
    # Your code here

Need a hint?

Use an if statement to check linting_enabled and call the lint function.