Frozen Waymos

Frozen Waymos

The recent news of Frozen Waymos backed up San Francisco traffic during a widespread power outage got me thinking. It wasn't just a traffic snarl; it was a stark reminder of how deeply integrated, yet inherently fragile, our automated systems can be when faced with unexpected external disruptions. We rely on these smart systems to make our lives easier, but what happens when the very infrastructure they depend on crumbles?

As someone who lives and breathes Google Apps Script (GAS), this incident resonated deeply with my own experiences in building and maintaining automated solutions. While my scripts aren't navigating city streets, they often perform critical background tasks, fetching data, updating spreadsheets, and sending notifications. The underlying principle is the same: automation is powerful, but its reliability is only as strong as its weakest link – be it a power grid, an internet connection, or an external API.

In my 5 years of extensive work with GAS, I've seen firsthand how seemingly minor external factors can bring an entire system to a grinding halt. You might be surprised to know that even the most robustly coded scripts can falter when the environment changes unexpectedly. It forces us, as developers, to think beyond the code itself and consider the broader ecosystem.


For instance, I once built a complex inventory management system for a small business, entirely powered by GAS. It pulled product data from an external e-commerce platform via their API. Everything worked flawlessly for months until one morning, reports stopped coming in. After some frantic debugging tips and digging, I discovered that the e-commerce platform had silently updated their API authentication method. My script, which used UrlFetchApp.fetch() with the old authentication headers, was suddenly getting 401 Unauthorized errors. It was a classic "Waymo moment" for my script – frozen and unable to proceed, not due to an error in my logic, but because of an external shift.

This isn't an isolated incident. The ambition of tech companies wanting flying taxis on the battlefield highlights a future where automation is not just convenient, but mission-critical. Such systems demand an unparalleled level of resilience, self-diagnosis, and adaptability. What happens when a network connection drops mid-flight? Or a GPS signal is jammed? These are the extreme versions of the challenges we face daily in smaller-scale automation with GAS.

The beauty of GAS, despite its cloud-dependent nature, is its accessibility and power. It allows us to automate complex workflows with relative ease. However, this ease can sometimes lead to overlooking crucial aspects of fault tolerance. My regular programming discussions with fellow developers often revolve around how to make our scripts more robust. It's a constant battle against the "what ifs."

One of the most valuable lessons I've learned is the importance of comprehensive error handling and logging. When building a daily report generator that aggregated data from multiple Google Sheets and external APIs, I ran into intermittent QuotaService errors. These weren't always predictable; sometimes they'd appear during peak usage, other times seemingly at random. Without proper logging, it would have been a nightmare to diagnose.


My solution involved implementing a robust try...catch block around every critical API call and external data fetch. Inside the catch block, I wouldn't just log the error; I'd also include details like the timestamp, the specific function that failed, and relevant input parameters. I even set up an automatic retry mechanism with exponential backoff for known transient errors. This approach, a staple in popular programming topics like distributed systems, proved invaluable.

function fetchDataWithRetry(url) {
  let retries = 3;
  while (retries > 0) {
    try {
      const response = UrlFetchApp.fetch(url);
      return response.getContentText();
    } catch (e) {
      Logger.log(`Error fetching ${url}: ${e.message}. Retries left: ${retries - 1}`);
      Utilities.sleep(1000 * (4 - retries)); // Exponential backoff
      retries--;
    }
  }
  throw new Error(`Failed to fetch ${url} after multiple retries.`);
}

This wasn't just about catching errors; it was about understanding the context of the failure. I once made a mistake, early in my career, of simply logging e.message without any context. When a script failed, all I got was a generic message like "Service invoked too many times for one day." Without knowing which service call, when, or why, debugging became a guessing game. Adding context to logs is one of those debugging tips that sounds obvious but is often overlooked in the heat of development.

A robust system isn't one that never fails, but one that fails gracefully, tells you why, and ideally, recovers on its own.

Another critical lesson: never assume external data formats will remain static. I learned this the hard way when a client's spreadsheet, which my GAS script parsed daily, had a column header subtly changed from "Product ID" to "Product Identifier." My script, using spreadsheet.getRangeByName('Product ID'), suddenly failed to find the range. It was a simple fix once identified, but the script had been silently failing for days, leading to outdated reports. This is why I now advocate for defensive coding, especially when dealing with user-managed data sources. Always validate inputs!

Here are some of my go-to debugging tips for GAS:

  1. Use Logger.log() extensively: Don't just log errors; log key variables, function entries/exits, and API responses. It's your window into execution.
  2. Utilize the Execution Log: Found under the "Executions" tab in the GAS editor. It's invaluable for seeing what actually happened, especially for timed triggers.
  3. Step-through Debugger: When a script consistently fails, use the built-in debugger. Set breakpoints and inspect variable values. It's like having X-ray vision.
  4. Version Control: Link your GAS project to a Google Cloud Platform (GCP) project and use Cloud Source Repositories. This allows for proper versioning and easier rollback if a change breaks something.
  5. Error Notifications: Implement a mechanism to notify you (e.g., email, Slack message) when a script fails. Don't wait for users to report issues.

These aren't just good practices; they're essential for building reliable automation. Just as Waymo needs to anticipate every possible road hazard and system failure, our GAS scripts need to be built with a similar mindset of resilience.


The broader implications of automation failures, from Frozen Waymos backed up San Francisco traffic during a widespread power outage to critical battlefield systems, underscore the importance of robust software engineering principles. Whether it's a multi-million dollar autonomous vehicle or a simple GAS script automating a spreadsheet, the core challenge remains the same: how do we build systems that can withstand the unpredictable chaos of the real world?

Always consider external dependencies. Your script might be perfect, but its environment might not be.

I find that many programming discussions around serverless functions and microservices touch upon these exact points. GAS, in essence, is a serverless platform, and many of the best practices for building robust cloud functions apply directly. Think about idempotent operations, graceful degradation, and circuit breakers – concepts that can be adapted even for simpler GAS projects.

AspectGAS (Google Apps Script)Local Script (e.g., Python)
Execution EnvironmentGoogle Cloud PlatformLocal machine/dedicated server
Dependency on CloudHigh (internet, Google services)Low (local resources)
Initial SetupVery low, browser-basedRequires environment setup
ScalabilityManaged by Google, quota limitsScales with hardware/infrastructure
External Outage ImpactDirectly affected by Google/internet outagesAffected by local power/network

Ultimately, the goal isn't just to write code that works, but code that keeps working, even when the world around it doesn't. This mindset, born from countless hours of debugging tips and real-world project failures, is what transforms a functional script into a truly reliable solution.

How can GAS scripts be made more resilient to external outages?

In my experience, the key lies in defensive programming and external monitoring. Implement robust try...catch blocks, especially around UrlFetchApp calls or interactions with Google services. Consider storing critical configuration data locally within the script or in a fallback Google Sheet, rather than relying solely on external APIs. Also, set up external monitors (e.g., UptimeRobot for web apps, or a simple time-driven trigger that pings itself) to detect failures and notify you promptly.

What are common pitfalls when integrating GAS with external services?

I've often seen issues arise from neglecting API rate limits or changes in API specifications. Always read the API documentation carefully and implement proper backoff strategies for retries. Another common pitfall is insecure handling of API keys; never hardcode them directly into your script. Use PropertiesService or a secure external store. Finally, inconsistent data formats from external sources can silently break scripts, so always validate and sanitize incoming data.

Are there specific debugging tips for complex GAS projects?

Absolutely. For complex projects, I swear by modularizing your code into smaller, testable functions. This makes it easier to isolate issues. Use the built-in debugger extensively; it's a lifesaver for stepping through logic. Don't underestimate the power of Logger.log(), but be strategic about what you log – too much noise can be as bad as too little. Finally, consider setting up a dedicated "test environment" (e.g., a separate set of Google Sheets or a sandbox API) to test changes before deploying to production.

Source:
www.siwane.xyz
A special thanks to GEMINI and Jamal El Hizazi.

About the author

Jamal El Hizazi
Hello, I’m a digital content creator (Siwaneˣʸᶻ) with a passion for UI/UX design. I also blog about technology and science—learn more here.
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