Component

Definition

A component is a process/bunch of processes that need to be executed as a unit. An example of a component is an application, cache, datastore. It is used as a building block in Services. Components cannot exist on their own; they exist only as a part of a service.

Every component is of a pre-defined type, which has default fields set. These fields can be optionally overridden(as and when they are whitelisted on the backend on a case-to-case basis).

Specification

Key	Value Type
type	string - all supported component types
name	string
version	string - all supported component versions
config	map - see config section for more info

Example

Below is a specification to define a component of type cassandra with version 3.11.8

{
    "type": "cassandra",
    "name": "foo-cassandra",
    "version": "3.11.8",
    "config": {
        ...CONFIG_FROM_DESCRIBE_COMMAND
    }
}

Example for application

{
    "type": "application",
    "name": "graphql",
    "version": "1.0.0",
    "config": {
        "build_type": "java",
        "build_version": "8",
        "port": 2000,
        "liveness_endpoint": "health",
        "readiness_endpoint": "health",
        "discovery": "both"
    }
}

Pro Tip

application component-type can be used for http application, crons , kafka-consumer

Supported Discovery Type

*Applicable only for component type application

Supported Discovery Type	Comment
public	service will be publicly available
private	available for internal discovery
both	open to both public and private network
none	used to disable discovery e.g. in case of kafka-consumer where the application is not discoverable

Available config for a component

Every component exposes config with options that can be accessed by.

odin describe component-type --name application

...component-defintion

List of exposed configs :

*Config*                  | *Mandatory* | *Data Type* |
config.build_type         | true        | string      |
config.build_version      | true        | string      |
config.discovery          | false       | string      |
config.liveness_endpoint  | false       | string      |
config.port               | false       | integer     |
config.readiness_endpoint | false       | string      |
name                      | true        | string      |
type                      | true        | string      |
version                   | true        | string      |

Read more about exposed configs here - Component Type reference