Include directive for modular config in Nginx - Step-by-Step Execution

Process Flow - Include directive for modular config

Start nginx config

↓

Read main config file

↓

Find include directive?

No→Continue parsing

Yes↓

Load included file(s)

↓

Parse included file(s)

↓

Merge settings

↓

Complete config parsing

↓

Start nginx with full config

Nginx reads the main config file, finds include directives, loads and parses included files, then merges all settings before starting.

Execution Sample

Nginx

http {
    include mime.types;
    server {
        listen 80;
    }
}

This config includes the mime.types file inside the http block, then defines a server listening on port 80.

Process Table

Step	Action	File Processed	Directive Found	Result
1	Start parsing main config	nginx.conf	No	Continue
2	Encounter include directive	nginx.conf	include mime.types;	Load mime.types file
3	Parse included file	mime.types	No	Add mime types to config
4	Return to main config	nginx.conf	No	Continue parsing
5	Parse server block	nginx.conf	No	Add server config
6	Finish parsing	nginx.conf + mime.types	No	Complete config
7	Start nginx with full config	N/A	N/A	Nginx running with merged config

💡 All config files parsed and merged; nginx starts with complete configuration.

Status Tracker

Variable	Start	After Step 2	After Step 3	After Step 5	Final
Config Content	Empty	Includes mime.types directive	mime.types content added	Server block added	Full merged config

Key Moments - 3 Insights

Why does nginx load another file when it sees the include directive?

Because the include directive tells nginx to read and merge the contents of the specified file into the current config, as shown in execution_table step 2 and 3.

What happens if the included file has errors?

Nginx will fail to start or reload because it parses included files as part of the main config, so errors in included files stop the whole config parsing (related to step 3).

Can include directives be nested?

Yes, included files can themselves contain include directives, and nginx will recursively load them until all are processed, similar to steps 2 and 3 repeated.

Visual Quiz - 3 Questions

Look at the execution table, at which step does nginx parse the included file?

A Step 2

B Step 3

C Step 5

D Step 7

💡 Hint

Check the 'File Processed' and 'Directive Found' columns in step 3.

According to the variable tracker, what is added to the config after step 3?

A Server block

B Empty config

C mime.types content

D Include directive

💡 Hint

Look at the 'Config Content' row after step 3 in variable_tracker.

If the include directive was missing, what would happen in the execution table?

A Step 2 would not find include directive and skip loading files

B Nginx would fail to start

C Step 3 would parse mime.types anyway

D Server block would not be parsed

💡 Hint

Refer to step 1 and 2 where include directive presence controls loading.

Concept Snapshot

Include directive in nginx config:
- Syntax: include filename;
- Used to modularize config by loading external files
- Nginx reads included files as part of main config
- Errors in included files affect whole config
- Supports nested includes for complex setups

Full Transcript

The include directive in nginx configuration allows splitting the main config into smaller files. When nginx parses the main config, it looks for include directives. Upon finding one, it loads and parses the specified file, merging its content into the main configuration. This process continues until all includes are resolved. This modular approach helps organize configuration and reuse common settings. Errors in any included file will cause nginx to fail to start or reload. The execution table shows step-by-step how nginx processes the main config and included files, while the variable tracker shows how the configuration content grows as files are included. Understanding this flow helps beginners grasp how nginx builds its full configuration from multiple files.