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Registry Svc

The registry service is designed to maintain a database of service definitions, service instances and nodes.

This page provides a high-level overview of Registry Svc. For detailed information, refer to the Registry Svc API documentation.

Entities​

Definition​

A Definition or service definition consists of the following things:

  • An ID
  • A container image to run and some additional information like the internal port exposed etc.
  • A set of endpoint definitions (OpenAPI etc.)
  • The URL of different clients (JS, Go etc.)

A Definition is an abstract concept that can not be called. For a callable entity look at Instances. Definitions are basically things you can deploy as an instance with a deployment.

Container based definition​

id: test-a
image:
  name: hashicorp/http-echo
  port: 8080
hostPort: 8887

Notes​

HostPorts are a temporary requirement until support for dynamic port assignment lands.

Source code based definition​

id: test-b
repository:
  url: https://github.com/1backend/1backend.git
  containerFile: server/docker/Dockerfile
hostPort: 9998

Instance​

A Instance or a service instance is an actual running, callable instance of a Definition.

A Instance consists of the following things:

  • Address information that can be used to internally address the Instance.
  • A Deployment ID.

Deployment​

Definitions become instances through the Deployment entity of the Deploy Service.

Node​

A Node is a physical or virtual machine that runs a 1Backend server. Maintaining a list of nodes is important so the daemon can efficiently distribute workload across the nodes. It's the basis for all distributed features.

This is how a well configured node should look like:

$ oo nodes lis
NODE ID    URL                                  LAST HEARTBEAT
myNodeId   http://myNetworkInternalHost:58231   8s ago

For well configured nodes, the following must be present

  • Each node should have a unique URL (eg. 127.0.0.1 for all nodes is not unique...)
  • Each node URL should be addressable by every node including themselves
  • A node ID should be defined to avoid the more error prone ID generation

Here is how a suboptimally configured node looks like:

$ oo nodes lis
NODE ID           URL                         LAST HEARTBEAT
node_eIfnt9CGJV   http://127.0.0.1:58231      8s ago

For single node setups that can work, but not if you plan to use distributed features.

To configure the nodes, please see the OB_SELF_URL and OB_NODE_ID envars here

How It Works​

The registry is needed when you want to call services not included in the 1Backend server. You can think of the daemon as the standard library and services in the registry as third party libraries.

When you want to call a service, you can ask the registry to provide you with a list of instance addresses for a service by service slug. Then you can use any of those instance addresses to make a call.

Things like load balancing should be done on the client side at the moment, the damon does not provide a Proxy Svc yet.