kronos-service

Base service implementation

API

Table of Contents

• DESCRIPTION
• Service
  • stateChanged
  • rejectWrongState
  • timeoutForTransition
  • _restart
  • restartIfRunning
  • toString
  • toJSONWithOptions
  • name
  • autostart
  • _configure
  • configure
  • log
  • endpointParentSeparator
  • configurationAttributes
  • endpoints
• ServiceLogger
  • autostart
  • name
  • endpoints
• ServiceConfig
  • autostart
  • name
• defineServiceConsumerProperties
• ServiceProviderMixin
• InterceptorProviderMixin
• EndpointsMixin
• endpoints

DESCRIPTION

key of the service description

Service

Extends EndpointsMixin(StateTransitionMixin(LogLevelMixin(events), prepareActions({ start: { stopped: { target: 'running', during: 'starting', rejected: 'failed', timeout: 5000 } }, restart: { stopped: { target: 'running', during: 'starting', rejected: 'failed', timeout: 5000 }, running: { target: 'running', during: 'restarting', timeout: 5000 } }, stop: { running: { target: 'stopped', during: 'stopping', rejected: 'failed', timeout: 5000 }, starting: { target: 'stopped', during: 'stopping', rejected: 'failed', timeout: 5000 }, failed: { target: 'stopped', during: 'stopping', rejected: 'failed', timeout: 1000 } } }), 'stopped'))

Service The initial state is 'stopped' All services have at least three endpoints:

• log out: log events
• config in: configuration request
• command in: administrative actions to be executed by the step

Parameters

• config Object
  • config.logLevel string
  • config.description string
  • config.endpoints Object
• owner Service

stateChanged

Called when the service state changes. Emits a serviceStateChanged event to the owner

Parameters

• oldState string
• newState string

rejectWrongState

Called when state transition is not allowed

Parameters

• action string originating action name

• Throws any always

timeoutForTransition

Deliver transtion timeout

Parameters

• transition Object

Returns number milliseconds before throwing for a logn running transition

_restart

Restart action default implementation does a _stop() and a _start()

Returns Promise fulfills after start

restartIfRunning

Restarts if in running mode Otherwise does nothing

Returns Promise resolves when restart is done (or immediate if no restart triggered)

toString

Returns the string representation of this step

Returns string human readable name

toJSONWithOptions

Deliver json representation

Parameters

• options Object (optional, default {})
  • options.includeRuntimeInfo boolean include runtime informtion like state
  • options.includeDefaults boolean include default endpoints
  • options.includeName boolean include name of the service
  • options.includeConfig boolean include config attributes

Returns Object json representation

name

defaults to the type

Returns string type

autostart

Should we start when beeing registered

Returns boolean false

_configure

Takes attribute values from config parameters and copies them over to the object. Copying is done according to configurationAttributes Which means we loop over all configuration attributes and then for each attribute decide if we use the default, call a setter function or simply assign the attribute value

Parameters

• config Object

Returns Set of modified attributes

configure

Use new configuration. Internally calls _configure(config) as the constructor does If attribute with needsRestart are touched the restartIfRunning method will be called

Parameters

• config Object

Returns Promise fillfills when config is applied

log

Adds service name to the log event

Parameters

• level string the log level
• arg Object log content

endpointParentSeparator

Returns string separator between service name and endpoint name

configurationAttributes

Meta information for the config attributes.

• default optional default value of the attribute
• needsRestart optional modification requires a service restart
• setter(newValue,attrribute) optional function to be used if simple value assignment is not enough The Service class only defines the logLevel, ans start timeout attribute

Returns Object

endpoints

Definition of the predefined endpoints

• log out
• config in
• command in

Returns Object predefined endpoints

ServiceLogger

Extends Service

Log receiving service

Parameters

• config
• owner

autostart

We always start immediate

Returns boolean true

name

Returns string 'logger'

endpoints

Adds a log input endpoint to the set of Service endpoints

Returns Object predefined endpoints

ServiceConfig

Extends Service

Config providing service Dispatches config requests to services or preserves them until a maching service becomes avaliable

Parameters

• config
• owner

autostart

We always start immediate

Returns boolean true

name

Returns string 'config'

defineServiceConsumerProperties

assign services based on a configuration

Parameters

• target Object object
• config Object service defintion
• provider Object service provider
• waitUntilFactoryPresent boolean

ServiceProviderMixin

Provide services and hold service configuration. By default a service provider has two build in services 'logger' and 'config'.

Parameters

• superclass

InterceptorProviderMixin

Register & provide Interceptors.

Parameters

• superclass

EndpointsMixin

Endpoint accessor mixin Manages endpoints in a container

Parameters

• superclass Class class to be extended

Returns Class extended class

endpoints

default set of endpoints to create

Returns Object {} empty set

install

With npm do:

npm install kronos-service

license

BSD-2-Clause