Configuration and Registry
EdgeX uses the 3rd party Consul microservice as the implementations for Configuration and Registry. The RESTful APIs are provided by Consul directly, and several communities supply Consul client libraries for different programming languages, including Go (official), Python, Java, PHP, Scala, Erlang/OTP, Ruby, Node.js, and C#.
EdgeX 2.0
New for Edgex 2.0 is Secure Consul when running EdgeX in secure mode. See the Secure Consul section for more details.
For the client libraries of different languages, please refer to the list on this page:
Configuration Management
For the current API documentation, please refer to the official Consul web site:
https://www.consul.io/intro/getting-started/kv.html https://www.consul.io/docs/agent/http/kv.html
Service Registry
For the current API documentation, please refer to the official Consul web site:
https://www.consul.io/intro/getting-started/services.html https://www.consul.io/docs/agent/http/catalog.html https://www.consul.io/docs/agent/http/agent.html https://www.consul.io/docs/agent/checks.html https://www.consul.io/docs/agent/http/health.html
Service Registration
While each microservice is starting up, it will connect to Consul to register its endpoint information, including microservice ID, address, port number, and health checking method. After that, other microservices can locate its URL from Consul, and Consul has the ability to monitor its health status. The RESTful API of registration is described on the following Consul page:
https://www.consul.io/docs/agent/http/agent.html#agent_service_register
Service Deregistration
Before microservices shut down, they have to deregister themselves from Consul. The RESTful API of deregistration is described on the following Consul page:
https://www.consul.io/docs/agent/http/agent.html#agent_service_deregister
Service Discovery
Service Discovery feature allows client micro services to query the endpoint information of a particular microservice by its microservice IDor list all available services registered in Consul. The RESTful API of querying service by microservice IDis described on the following Consul page:
https://www.consul.io/docs/agent/http/catalog.html#catalog_service
The RESTful API of listing all available services is described on the following Consul page:
https://www.consul.io/docs/agent/http/agent.html#agent_services
Health Checking
Health checking is a critical feature that prevents using services that are unhealthy. Consul provides a variety of methods to check the health of services, including Script + Interval, HTTP + Interval, TCP + Interval, Time to Live (TTL), and Docker + Interval. The detailed introduction and examples of each checking methods are described on the following Consul page:
The health checks should be established during service registration. Please see the paragraph on this page of Service Registration section.
Consul UI
Consul has UI which allows you to view the health of registered services and view/edit services' individual configuration. Learn more about the UI on the following Consul page:
https://learn.hashicorp.com/tutorials/consul/get-started-explore-the-ui
EdgeX 2.0
Please note that as of EdgeX 2.0, Consul can be secured. When EdgeX is running in secure mode with secure Consul, you must provide Consul's access token to get to the UI referenced above. See How to get Consul ACL token for details.