The blog post "Nginx: try_files is evil too" argues against using the try_files directive in Nginx configurations, especially for serving static files. While seemingly simple, its behavior can be unpredictable and lead to unexpected errors, particularly when dealing with rewritten URLs or if file existence checks are bypassed due to caching. The author advocates for using simpler, more explicit location blocks to define how different types of requests should be handled, leading to improved clarity, maintainability, and potentially better performance. They suggest separate location blocks for specific file types and a final catch-all block for dynamic requests, promoting a more transparent and less error-prone approach to configuration.
The blog post "Nginx: try_files Is Evil Too (2024)" argues against the common practice of using the try_files directive in Nginx configurations, particularly when serving static files. While often presented as a simple and efficient solution, the author contends that try_files introduces subtle inefficiencies and complexities that ultimately hinder performance and maintainability.
The core issue lies in how try_files handles requests. It sequentially checks for the existence of files specified in its arguments. For a typical setup attempting to serve a file directly and falling back to an index file (e.g., try_files $uri $uri/ /index.html), this means Nginx will first check for the requested URI as a file, then as a directory, before finally resorting to the index.html. This sequential checking introduces unnecessary system calls, especially when the requested resource is often the index.html itself, for single-page applications or other web apps where the server ultimately serves the same HTML file for different routes. These extra checks add latency, particularly noticeable under heavy load.
The author proposes that a more efficient approach is to use a combination of location blocks with more specific matching rules. By separating the handling of static files (like images, CSS, and JavaScript) from the handling of requests that should be routed to the application's entry point (usually index.html), Nginx can avoid the redundant checks introduced by try_files. This method involves defining a location block for static assets, allowing Nginx to serve them directly. Another location block, typically a catch-all or more specific route handler, would then serve the index.html. This approach eliminates the need for try_files to iterate through multiple possibilities and ensures that Nginx serves the correct resource with minimal overhead.
Furthermore, the post highlights the potential for confusion and misconfiguration when using try_files, particularly when dealing with nested locations or more complex routing scenarios. The sequential nature of try_files can make it difficult to predict the exact behavior in such cases, leading to unexpected results and debugging challenges. The more structured approach of using distinct location blocks provides greater clarity and control, making the configuration easier to understand and maintain.
In conclusion, the author advocates for abandoning try_files in favor of a more precise and efficient approach based on distinct location blocks. This method eliminates unnecessary file system checks, improves performance, and enhances the maintainability of Nginx configurations by providing a clearer and more predictable structure. The post champions the use of explicit configuration over the perceived simplicity of try_files, ultimately resulting in a faster and more robust server setup.
Summary of Comments ( 4 )
https://news.ycombinator.com/item?id=43078696
Hacker News commenters largely disagree with the article's premise that
try_filesis inherently "evil." Several point out that the author's proposed alternative usinglocationblocks with regular expressions is less performant and more complex, especially for simpler use cases. Some argue that the author mischaracterizestry_files's purpose, which is primarily for serving static files efficiently, not complex routing. Others agree thattry_filescan be misused, leading to confusing configurations, but contend that when used appropriately, it's a valuable tool. The discussion also touches on alternative approaches, such as using a separate frontend proxy or load balancer for more intricate routing logic. A few commenters express appreciation for the article prompting a re-evaluation of their Nginx configurations, even if they don't fully agree with the author's conclusions.The Hacker News post titled "Nginx: try_files Is Evil Too (2024)" has generated a number of comments discussing the nuances and potential drawbacks of using the
try_filesdirective in Nginx configuration. Several commenters agree with the author's premise, pointing out thattry_filescan lead to unexpected behavior and difficult-to-debug issues, especially when dealing with redirects or more complex setups.One compelling argument revolves around the inherent ambiguity of
try_files. A commenter highlights how it can be unclear whether a 404 error stems from a missing file or a misconfiguredtry_filesdirective. This lack of clarity can complicate troubleshooting, particularly in production environments.The discussion also delves into the performance implications of
try_files. Some commenters argue that, while convenient, it can introduce unnecessary overhead, particularly when used for simple static file serving. Alternatives like serving files directly or employing more specific location blocks are suggested as potentially more efficient solutions.Another significant point raised is the maintainability challenges associated with
try_files. Complex configurations usingtry_filescan become difficult to understand and modify over time, especially as a project grows and evolves. This can lead to accidental errors and make it harder for new team members to onboard.Several commenters offer alternative approaches to achieving similar functionality without resorting to
try_files. These include usinglocationblocks with more specific matching rules and leveraging therootdirective for simpler file serving scenarios. Specific examples and configurations are provided, showcasing how these alternatives can provide more clarity and control.The conversation also touches upon the historical context of
try_files, with some commenters suggesting that its prevalence is partly due to legacy reasons and outdated documentation. They advocate for moving towards more modern and explicit configuration practices.Finally, the thread also features a discussion on the importance of understanding the underlying mechanisms of Nginx and the potential pitfalls of relying solely on seemingly simple directives like
try_files. The overall sentiment encourages a more deliberate and informed approach to Nginx configuration, emphasizing clarity, maintainability, and performance.