Learn how to enable Brotli compression for Nginx Docker. Our Docker Support team is here to help you with your questions and concerns.

How to enable Brotli Compression for Nginx Docker

Brotli can be defined as a data compression algorithm that relies on a variant of the LZ77 algorithm, Huffman coding, and second‑order context modeling.

Furthermore, its compression ratio stands at par with the best current general‑purpose compression methods. In fact, Brotli’s speed is similar to DEFLATE. However with denser compression.

The ngx_brotli module lets us enable Brotli compression in NGINX Plus. It has two modules as seen here:

• ngx_brotli filter module – it compresses responses dynamically
• ngx_brotli static module – it serves pre-compressed files

By enabling the Brotli plugin for Nginx, we can save server bandwidth and speed up pages. Since this plugin is not included by default, we have to do it manually.

This can be done by pushing the built image to Github’s Docker registry.

docker pull ghcr.io/zvonimirsun/nginx:stable-alpine-brotli

We have to compile google/ngx_brotli with the correct version of Nginx. Then add the compiled plugin so file into the official image. This will help us load the module dynamically.

Before we begin, here is a little note on Dockerfile:

Furthermore, the configure parameters are an exact copy of the official image parameters, except for the add-dynamic-module. This module is used to add brotli.

How to Enable Brotli Compression

We can use the image built from this Dockerfile above. Once, the Brotli module file is added to the image, it can be introduced dynamically.

So, we have to add this to the beginning of nginx.conf file:

load_module /usr/lib/nginx/modules/ngx_http_brotli_filter_module.so;
load_module /usr/lib/nginx/modules/ngx_http_brotli_static_module.so;


Furthermore, we have to add the following to the HTTP section so that gzip and Brotli can work together:

Once we check the configuration with nginx -t, it is time to apply the configuration with this command:

nginx -s reload

In some cases, an error may occur, especially if we install brotli in alpine. This results in a folder /etc/nginx/modules that is not linked to the modules-enabled.

This will lead to a mismatch between the compiled version of nginx and the module. The answer is to fetch them from the same source. So rather than using nginx:alpine, we can use alpine.

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Conclusion

In brief, our Support Experts demonstrated how to enable Brotli compression for Nginx Docker.