22 config center

ADNC Configuration Center: Consul

GitHub Repository

ADNC supports two modes for loading configurations:

• File: Reads from local appsettings files (default for local development).
• Consul: Reads from Consul Key-Value (KV) store (recommended for Staging/Production).

---

0. Quick Start

1. Start Consul.
2. Add configurations to Consul KV (typically a shared config and a service-specific config).
3. Set ConfigurationType to Consul in your service's appsettings.json.
4. Configure ConsulUrl and ConsulKeyPath.
5. Start the service. Configurations are refreshed automatically (polling).

1. Configuration Loading Process

When a service starts, it calls AddConfiguration:

• File Mode: Loads appsettings.shared.{Environment}.json from the execution directory.
• Consul Mode: Connects to ConsulUrl and loads the keys specified in ConsulKeyPath.
• Placeholder Replacement: After loading, the system automatically replaces placeholders like $SERVICENAME, $SHORTNAME, and $RELATIVEROOTPATH.

2. Switching to Consul

Example configuration for a Staging environment:

{
  "ConfigurationType": "Consul",
  "Consul": {
    "ConsulUrl": "http://172.80.0.4:8500",
    "ConsulKeyPath": "adnc/staging/shared/appsettings,adnc/staging/$SHORTNAME/appsettings"
  }
}

• ConsulUrl: The HTTP API address of your Consul instance.
• ConsulKeyPath: Comma-separated paths to KV keys. They are loaded in order.
• $SHORTNAME: Automatically replaced with the service's short name (e.g., cust-api).

3. Organizing KV Keys (Shared + Specific)

We recommend a two-layer configuration strategy:

1. Shared Config (adnc/{env}/shared/appsettings): Contains common settings like Redis, RabbitMQ, Polly, and SkyWalking.
2. Service-Specific Config (adnc/{env}/{shortName}/appsettings): Overrides or adds settings specific to that service (e.g., DB connection strings).

The KV values should be valid JSON strings.

4. Dynamic Updates (Hot Reload)

When using Consul, ADNC enables reloadOnChanges=true. The Consul provider polls the KV store every 3 seconds. If the LastIndex changes, the configuration is reloaded and placeholders are re-processed.

Note: While configurations reload, some components that cache settings on startup may still require a restart to reflect changes.

5. Initializing Consul KV

The repository includes scripts to initialize a Demo environment:

• Scripts: doc/devops-staging/adnc-consul/consul-init.sh
• Initial Data: doc/devops-staging/adnc-consul/kv.json

---

If this helps, please Star & Fork.