ConnectionResolver

Helper class used to retrieve component connections.

Description

The ConnectionResolver class is used to retrieve component connections.

Important points

  • If the connections are configured to be retrieved from IDiscovery, the connection resolver will automatically locate IDiscovery in component references and retrieve the connections from there using the discovery_key parameter.

Configuration parameters

connection:

  • discovery_key: (optional) a key to retrieve the connection from IDiscovery
  • … : other connection parameters

connections: alternative to connection

  • [connection params 1]: first connection parameters
    • … : connection parameters for key 1
  • [connection params N]: Nth connection parameters
    • … : connection parameters for key N

References

  • *:discovery:*:*:1.0 - (optional) IDiscovery services to resolve connections

Constructors

Creates a new instance of connection resolver.

public constructor(config: ConfigParams = null, references: IReferences = null)

  • config: ConfigParams - (optional) component configuration parameters
  • references: IReferences - (optional) component references

Instance methods

add

Adds a new connection to component connections

public add(connection: ConnectionParams): void

configure

Configures component by passing configuration parameters.

public configure(config: ConfigParams): void

  • config: ConfigParams - configuration parameters to be set.

getAll

Gets all connections configured in component configuration. Redirect to Discovery services is not done at this point. If you need fully fleshed connection use resolve method instead.

public getAll(): ConnectionParams[]

register

Registers the given connection in all referenced discovery services. This method can be used for dynamic service discovery.

public register(context: IContext, connection: ConnectionParams): Promise<void>

  • context: IContext - (optional) a context to trace execution through call chain.
  • connection: ConnectionParams - a connection to register.

resolve

Resolves a single component connection. If connections are configured to be retrieved from Discovery service it finds a IDiscovery and resolves the connection there.

public resolve(context: IContext): Promise<ConnectionParams>

  • context: IContext - (optional) a context to trace execution through call chain.
  • returns: Promise<ConnectionParams> - resolved connection parameters or null if nothing was found.

resolveAll

Resolves all component connection. If connections are configured to be retrieved from Discovery service it finds a IDiscovery and resolves the connection there.

public resolveAll(context: IContext): Promise<ConnectionParams[]>

  • context: IContext - (optional) a context to trace execution through call chain.
  • returns: Promise<ConnectionParams[]> - a list of resolved connections.

setReferences

Sets references to dependent components.

public setReferences(references: IReferences)

  • references: IReferences - references to locate the component dependencies.

Examples

let config = ConfigParams.fromTuples(
    "connection.host", "10.1.1.100",
    "connection.port", 8080
);
   
let connectionResolver = new ConnectionResolver();
connectionResolver.configure(config);
connectionResolver.setReferences(references);
  
let connection = await connectionResolver.resolve("123");
// Now use connection...

See also