What is the role of dispatcher.any and dispatcher.conf files?

The dispatcher.any and dispatcher.conf files are crucial configuration files for the AEM Dispatcher. They control how the Dispatcher behaves, including caching, load balancing, security, and URL rewriting. Let's break down their roles:

dispatcher.conf :

Main Configuration File: This is the primary configuration file for the Dispatcher. It includes general settings and references other configuration files, including dispatcher.any.
Global Settings: It defines global settings that apply to the entire Dispatcher instance, such as:
- LogLevel: Sets the logging level for the Dispatcher.
- PidFile: Specifies the process ID file.
- CacheRoot: Defines the directory where cached files are stored.
- Hostname: The hostname of the Dispatcher.
- Port: The port the Dispatcher listens on.
- Dispatchers section: Contains the include directives for dispatcher.any files.

dispatcher.any :

Farm Configurations: This file (or, more commonly, files included by dispatcher.conf) defines one or more "farms." A farm represents a set of configurations for a specific virtual host or website. You can have multiple farms in a single dispatcher.any file, allowing you to manage different websites with different configurations.
Farm-Specific Settings: Within each farm, you configure settings specific to that website, including:
- ClientHeaders: Defines which client headers are forwarded to the AEM publish instances.
- Caches: Configures caching rules, including which files to cache, how long to cache them, and how to invalidate the cache.
- Filters: Defines rules for allowing or denying access to specific content. This is essential for security.
- Render: Configures the connection to the AEM publish instances (hostname, port). This is where you set up load balancing.
- Rewrites: Defines URL rewriting rules.
- VirtualHosts: Defines the virtual hosts that this farm applies to.
- StickySession: Configures sticky sessions, which ensure that requests from the same user are directed to the same publish instance.

Relationship between the files:

dispatcher.conf acts as the entry point. It includes one or more dispatcher.any files. This allows you to organize your Dispatcher configuration into multiple files for easier management, especially when dealing with multiple websites or complex configurations.

Example (Simplified) :

# dispatcher.conf
...
Include /path/to/dispatcher.any  # Includes the farm configurations
...

# dispatcher.any
<Farm>
  Name "mywebsite"
  ClientHeaders {
    "Host"
    "User-Agent"
  }
  Caches {
    docroot "/var/www/html/cache"
    ...
  }
  Filters {
    /allow /*
  }
  Render {
    hostname "publish1"
    port "4502"
  }
  VirtualHosts {
    "www.example.com"
  }
</Farm>

In summary:

dispatcher.conf: The main configuration file, including global settings and references to dispatcher.any files.
dispatcher.any: Contains the configurations for one or more farms, defining settings for specific websites or virtual hosts.