Config Reload

The config-reload module provides admin endpoints to reload configuration files for specific modules or plugins at runtime without restarting the server. This is particularly useful in shared environments like a gateway where restarting would impact multiple services, or for dynamic updates to policies and rules.

Endpoints

The module typically exposes two operations on the same path (e.g., /adm/modules).

Get Registered Modules

• Path: /adm/modules
• Method: GET
• Description: Returns a list of all registered modules and plugins capable of being reloaded.
• Response: A JSON array of class names (Strings).

Trigger Config Reload

• Path: /adm/modules
• Method: POST
• Description: Triggers a config reload for the specified list of modules or plugins.
• Request Body: A JSON array of class names (Strings) to reload. If the list is empty or contains “ALL”, it attempts to reload all registered modules.
• Response: A JSON array of the class names that were successfully reloaded.

Configuration

Module Configuration (configreload.yml)

The module itself is configured via configReload.yml (or configReload.yaml/json).

Handler Configuration (handler.yml)

To expose the endpoints, you need to configure them in your handler.yml.

paths:
  - path: '/adm/modules'
    method: 'get'
    exec:
      - admin
      - modules
  - path: '/adm/modules'
    method: 'post'
    exec:
      - admin
      - configReload

And in values.yml (if using aliases):

handler.handlers:
  - com.networknt.config.reload.handler.ModuleRegistryGetHandler@modules
  - com.networknt.config.reload.handler.ConfigReloadHandler@configReload

Security

These are sensitive admin endpoints. They should be protected by OAuth 2.0 (requiring a specific scope like admin or ${serviceId}/admin) or restricted by IP whitelist in a sidecar/gateway deployment.

Dependency

Add the following dependency to your pom.xml:

<dependency>
  <groupId>com.networknt</groupId>
  <artifactId>config-reload</artifactId>
  <version>${version.light-4j}</version>
</dependency>

Usage Examples

List Modules

curl -k https://localhost:8443/adm/modules

Response:

[
    "com.networknt.limit.LimitHandler",
    "com.networknt.audit.AuditHandler",
    "com.networknt.router.middleware.PathPrefixServiceHandler",
    ...
]

Reload Config

Reload configuration for the Limit Handler and Path Prefix Handler.

curl -k -X POST https://localhost:8443/adm/modules \
  -H 'Content-Type: application/json' \
  -d '[
    "com.networknt.limit.LimitHandler",
    "com.networknt.router.middleware.PathPrefixServiceHandler"
  ]'

Response:

[
    "com.networknt.limit.LimitHandler",
    "com.networknt.router.middleware.PathPrefixServiceHandler"
]