Load Testing GraphQL APIs

Overview

LoadForge makes testing GraphQL APIs straightforward by utilizing standard HTTP POST requests to send GraphQL queries.

This guide demonstrates how to create a load test to query the missions from the publicly available SpaceX GraphQL API. The examples provided here can be adapted to test any GraphQL API, including authentication scenarios.

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Basic Example

Here's a fundamental example showing a standard GraphQL query that requests the mission IDs and names from the SpaceX API:

{
  missions {
    id
    name
  }
}

The following example shows how to implement this query for use in a LoadForge test, demonstrating the straightforward integration of GraphQL queries.

import time
from locust import HttpUser, task, between

class QuickstartUser(HttpUser):
    wait_time = between(3, 5)

    @task(1)
    def index_page(self):
        query = '''
            {
              missions {
                id
                name
              }
            }
            '''

        response = self.client.post(
            "/graphql",
            name="GraphQL",
            json={"query": query }
        )

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Authenticating GraphQL Requests

Many GraphQL APIs require authentication. The following example shows how to set custom headers for authentication:

    response = self.client.post(
        "/graphql",
        name="GraphQL",
        headers={
            "Accept": "application/graphql",
            "Authorization": "<Authorization-Token>"
        },
        json={"query": query}
    )

For dynamic authorization token retrieval, the on_start method can automate this process, ensuring all requests include the required authentication header:

    def on_start(self):
        # Send a login request
        response = requests.post("http://mysite.com/login", {"username": "user", "password": "pass"})

        # Extract the "token" from the response header
        self.client.headers.update({'Authorization': response.headers.get('token')})

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Locust Test Script (locust.py)

# locust.py
import time
from locust import HttpUser, between, task

class GraphQLUser(HttpUser):
    wait_time = between(1, 3)
    host = "https://api.spacex.land/graphql"

    def on_start(self):
        # Optionally disable SSL verification
        self.client.verify = False

    @task
    def fetch_missions(self):
        query = """
        {
          missions {
            id
            name
          }
        }
        """
        self.client.post(
            "/",
            name="GraphQL Query",
            json={"query": query}
        )

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