Orval sometimes gets 403 in GitHub Actions when fetching Swagger URL (works locally)

by

Summary

The issue at hand involves Orval, a Swagger client generator for TypeScript, encountering intermittent 403 Forbidden errors when fetching a Swagger JSON file in a GitHub Actions workflow. This issue does not occur when running the same process locally, suggesting an environment-specific problem. The randomness of the failure, with success often achieved after re-running the workflow without changes, points towards issues related to networking or server-side rate limiting.

Root Cause

The root cause of this issue can be attributed to several potential factors:

  • Rate Limiting: GitHub Actions’ IP addresses might be getting rate-limited by the server hosting the Swagger JSON, especially if multiple workflows are triggering the Orval step in quick succession.
  • CDN/WAF Configuration: The Content Delivery Network (CDN) or Web Application Firewall (WAF) protecting the Swagger endpoint might be configured to treat CI traffic as suspicious, leading to intermittent blocks.
  • Network Instability: Temporary network instability or connectivity issues within the GitHub Actions environment could also contribute to the problem.

Why This Happens in Real Systems

This issue occurs in real systems due to the following reasons:

  • CI/CD Pipeline Complexity: The nature of CI/CD pipelines, which can trigger a high volume of requests in a short time frame, can inadvertently trigger rate limiting or flags on security systems.
  • Security Measures: Modern web applications and APIs employ various security measures (like WAFs and CDNs) to protect against malicious traffic, which can sometimes incorrectly flag legitimate CI traffic.
  • Network Dynamics: The dynamic nature of cloud environments, such as those used by GitHub Actions, means that network conditions can vary, leading to occasional failures.

Real-World Impact

The real-world impact of this issue includes:

  • Intermittent Build Failures: The randomness of the failure can lead to build failures that are difficult to diagnose, causing delays in development and deployment processes.
  • Debugging Challenges: The intermittent nature makes it challenging to debug, as the issue may not reproduce consistently.
  • Reliability Concerns: It raises concerns about the reliability of the CI/CD pipeline, potentially leading to lost productivity as teams spend more time troubleshooting rather than developing.

Example or Code

import { defineConfig } from "orval";

const swaggerUrl = process.env.ORVAL_SWAGGER_URL;

if (!swaggerUrl) {
  throw new Error("ORVAL_SWAGGER_URL is missing");
}

export default defineConfig({
  base: {
    input: {
      target: `${swaggerUrl}/base/swagger.json`,
      // Custom headers could be added here if Orval supported them
    },
    //... rest of the config

How Senior Engineers Fix It

Senior engineers can approach this issue by:

  • Implementing Retry Mechanisms: Adding retry logic with exponential backoff to handle transient failures.
  • Configuring Custom Headers: If possible, configuring custom headers for Orval to identify CI traffic differently, although this might require modifying Orval or using a different client.
  • Contacting API Owners: Reaching out to the owners of the Swagger endpoint to whitelist GitHub Actions IPs or adjust rate limiting rules.
  • Optimizing CI/CD Workflow: Optimizing the CI/CD pipeline to reduce the frequency of requests to the Swagger endpoint.

Why Juniors Miss It

Junior engineers might miss this issue due to:

  • Lack of Experience with CI/CD: Inexperience with the complexities of CI/CD pipelines and how they interact with external services.
  • Insufficient Knowledge of Networking: Limited understanding of network dynamics, rate limiting, and security measures like CDNs and WAFs.
  • Debugging Challenges: The intermittent nature of the issue can make it hard to identify and debug, especially for those without extensive experience in troubleshooting complex system interactions.

Leave a Comment