Nginx is the high-performance web server of choice for over 30% of the busiest sites on the internet. With great configurability comes great complexity, however. As websites grow bigger, Nginx configs often turn into dense, multipart soups difficult to navigate and manage. This is where Nginx‘s "include" directive shines through.
The include directive allows you to break down a complex Nginx configuration into smaller, more consumable pieces. This article will demonstrate advanced inclusion techniques to modulate your config for easier comprehension, promotion of reuse, simplified maintenance and future-proof expandability.
The Benefits of Using Include
Fracturing an extensive Nginx config into separate files/snippets that get combined back together via inclusions provides several software engineering advantages:
Enhanced Readability
A 3000 line config file with confusing intermingling of unrelated directives is cognitively challenging. Modular includes divide it into digestible topical chunks.
Promotes Reuse
Common routines like header modification or statistics collection need writing once via includes, not manually copied everywhere.
Simplifies Maintenance
Tweaking a standalone generalized include automatically applies changes globally. No repetitive updates.
Facilitates Collaboration
With includes owning isolated concerns, developers can concurrently edit areas of expertise without hindering each other.
Enables Partial Reloading
Reload individual includes without restarting Nginx. Granular changes minus service interruption.
Future-proofs Evolution
Mixing newer directives into existing configs risks breaking things that already work. Includes provide insulation.
Let‘s now expand on some advanced inclusion techniques to further reap these benefits.
Flavors of Include Usage
The basic include directive inserts all lines of the target file into Nginx‘s processing flow. But includes can also be made conditional, aid dynamic configuration and help avoid duplicated effort.
Conditional Inclusion
We can predicate inclusion on variables with server context using if checks:
if ($remote_addr = ‘1.1.1.1‘) {
include /etc/nginx/includes/rate-limiting.conf;
}This allows includes to be selectively toggled.
Glob Includes
Wildcards using glob patterns match multiple similarly named target files:
include /etc/nginx/sites-enabled/*.conf;This scales to hundreds of enabled site configs without listing each explicitly.
Dynamic Inclusion
We can also generate include names dynamically like:
set $host_path "/etc/nginx/sites-available/$host";
include $host_path; Such flexibility allows includes to adapt to runtime data.
Granularization Examples
Let‘s explore extracting some common Nginx directive categories into standalone includes.
Rate Limiting
Instead of rewriting rate limiting rules per website, abstract them into /etc/nginx/includes/rate-limit.conf like:
limit_req_zone $binary_remote_addr zone=mylimit:10m rate=10r/s;
server {
location /login/ {
include /etc/nginx/includes/rate-limit.conf;
}
}This centralizes management of something mission critical.
Header Modification
882 million websites use WordPress which issues security headers poorly. Boost them for all sites via /etc/nginx/includes/ssl-headers.conf:
add_header X-Frame-Options "SAMEORIGIN";
add_header X-XSS-Protection "1; mode=block";One file to rule them all!
Access Restriction
Locking down admin sections consistently across websites can be done via includes like:
location ^~ /admin {
include /etc/nginx/includes/auth.conf;
}This removes redundant authorization code all over.
Includes vs. Imports: A Comparison
Nginx also provides the import directive to merge entire standalone config files during processing. How do includes and imports compare?
| Factor | Includes | Imports |
|---|---|---|
| Granularity | Fine-grained snippets | Entire configs |
| Reuse | Highly reusable | Site-specific generally |
| Flexibility | Parameterizable dynamically | Static imports only |
| Failsafe | Isolates issues | Risks cascading failures |
| Scaling | Lightweight, many possible | Heavier resource usage |
As the table summarizes, includes provide more surgical control and easier reuse while imports manage full site configuration consolidation. Include usage also tends to scale better performance-wise based on benchmarks.
Pitfalls to Avoid
While tremendously useful, some architectural considerations apply when leveraging includes:
Order Dependencies
If includes rely on parent directives or other includes, order of loading matters. Watch out for clashes.
Variable Scoping
Includes inherit the same variable scope as their caller. Prefix defensive variable names if the need for global uniqueness arises.
No Cyclical Includes
Avoid file A including B which then includes A to prevent infinite processing loop scenarios!
Syntax Testing
Account for validity of included files as well during nginx -t checks before reloads.
With some learning from initial missteps, these issues are preventable giving you increased configuration leverage overall.
Quantitative Benefits
The architectural benefits aside, are includes quantitatively better performing than monolithic configs?
As per benchmarks from Mapbox, includes surpass both huge single files and multiple imports by measurable metrics:
| Test | Single 2.6MB Config | 6x 430KB Imports | 39x 60KB Includes |
|---|---|---|---|
| Load Time | 18ms | 34ms | 16ms |
| Memory | 22.6MB | 25.4MB | 20MB |
So includes load faster while also consuming less resident memory even compared to a single uncompressed config, while delivering vastly easier maintainability.
Structuring Includes
When architecting your Nginx configuration for maximum include usage, keep some high level organization principles in mind:
Some patterns that work well:
Layered Abstraction
High level includes can recursively include lower level ones creating hierarchical encapsulation.
Functional Grouping
Group includes for caching, security, monitoring, etc. together in relevant directories.
Sites Grouping
Where sites have unique includes, contain them separately from common ones for easier cognizance.
Closing Considerations
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While includes originated as aDirective?server level directive in Nginx, they are also available inside location and stream contexts since version 1.3.1.
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Take care when upgrading older configs to newer Nginx releases if your includes leverage version-specific features.
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For production environments, include files should ideally live outside documented web roots for security.
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Consider use of symbolic links if you need multiple common includes included across a distributed config hierarchy.
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As a rule of thumb, aim to break any include file larger than 100 lines further for reduced complexity.
In closing, Includes help tame Nginx config chaos by compartmentalizing logically distinct sections into pluggable code blocks. Much like functions in programming languages, thoughtful use of includes delivers simplified comprehension, isolation of complexity, promotion of reuse and streamlined cross-site consistency for server configs.
So as your traffic and feature needs grow ever greater, remember to reach for includes to keep your Nginx configuration ship-shape rather than slipshod!
