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Time Sync Plugin

Version: 1.0

Status: ⚫⚫⚫

TimeSync plugin for Thunder framework.

Table of Contents

Introduction

Scope

This document describes purpose and functionality of the TimeSync plugin. It includes detailed specification about its configuration, methods and properties as well as sent notifications.

Case Sensitivity

All identifiers of the interfaces described in this document are case-sensitive. Thus, unless stated otherwise, all keywords, entities, properties, relations and actions should be treated as such.

Acronyms, Abbreviations and Terms

The table below provides and overview of acronyms used in this document and their definitions.

Acronym Description
API Application Programming Interface
HTTP Hypertext Transfer Protocol
JSON JavaScript Object Notation; a data interchange format
JSON-RPC A remote procedure call protocol encoded in JSON

The table below provides and overview of terms and abbreviations used in this document and their definitions.

Term Description
callsign The name given to an instance of a plugin. One plugin can be instantiated multiple times, but each instance the instance name, callsign, must be unique.

References

Ref ID Description
HTTP HTTP specification
JSON-RPC JSON-RPC 2.0 specification
JSON JSON specification
Thunder Thunder API Reference

Description

The Time Sync plugin provides time synchronization functionality from various time sources (e.g. NTP).

The plugin is designed to be loaded and executed within the Thunder framework. For more information about the framework refer to [Thunder].

Configuration

The table below lists configuration options of the plugin.

Name Type M/O Description
callsign string mandatory Plugin instance name (default: TimeSync)
classname string mandatory Class name: TimeSync
locator string mandatory Library name: libThunderTimeSync.so
startmode string mandatory Determines in which state the plugin should be moved to at startup of the framework
deferred boolean optional (deprecated) Determines if automatic time sync shall be initially disabled. This parameter is deprecated and SubSystemControl could be used instead
periodicity integer optional Periodicity of time synchronization (in hours), 0 for one-off synchronization
retries integer optional Number of synchronization attempts if the source cannot be reached (may be 0)
interval integer optional Time to wait (in milliseconds) before retrying a synchronization attempt after a failure
sources array mandatory Time sources
sources[#] string mandatory (a time source entry)

Interfaces

This plugin implements the following interfaces:

Methods

The following methods are provided by the TimeSync plugin:

TimeSync interface methods:

Method Description
synchronize Synchronizes time

synchronize method

Synchronizes time.

Description

Use this method to synchronize the system time with the currently configured time source. If automatic time synchronization is initially disabled or stopped, it will be restarted.

Parameters

This method takes no parameters.

Result

Name Type M/O Description
result null mandatory Always null (default: None)

Errors

Message Description
ERROR_INPROGRESS Returned when the method is called while previously triggered synchronization is in progress.
ERROR_INCOMPLETE_CONFIG Returned when the source configuration is missing or invalid.

Example

Request

{
  "jsonrpc": "2.0",
  "id": 42,
  "method": "TimeSync.1.synchronize"
}

Response

{
  "jsonrpc": "2.0",
  "id": 42,
  "result": null
}

Properties

The following properties are provided by the TimeSync plugin:

TimeSync interface properties:

Property R/W Description
synctime read-only Most recent synchronized time
time read/write Current system time

synctime property

Provides access to the most recent synchronized time.

This property is read-only.

Value

Name Type M/O Description
(property) object mandatory Most recent synchronized time
(property).time string mandatory Synchronized time (in ISO8601 format); empty string if the time has never been synchronized
(property)?.source string optional The synchronization source e.g. an NTP server

Example

Get Request

{
  "jsonrpc": "2.0",
  "id": 42,
  "method": "TimeSync.1.synctime"
}

Get Response

{
  "jsonrpc": "2.0",
  "id": 42,
  "result": {
    "time": "2019-05-07T07:20:26Z",
    "source": "ntp://example.com"
  }
}

time property

Provides access to the current system time.

Description

Upon setting this property automatic time synchronization will be stopped. Usage of this property is deprecated and the SubSystem control plugin can be used as an alternative to achieve the same

Value

Name Type M/O Description
(property) string mandatory System time (in ISO8601 format)
Name Type M/O Description
(property) string mandatory System time (in ISO8601 format)

Errors

Message Description
ERROR_BAD_REQUEST The time is invalid

Example

Get Request

{
  "jsonrpc": "2.0",
  "id": 42,
  "method": "TimeSync.1.time"
}

Get Response

{
  "jsonrpc": "2.0",
  "id": 42,
  "result": "2019-05-07T07:20:26Z"
}

Set Request

{
  "jsonrpc": "2.0",
  "id": 42,
  "method": "TimeSync.1.time",
  "params": "2019-05-07T07:20:26Z"
}

Set Response

{
    "jsonrpc": "2.0",
    "id": 42,
    "result": "null"
}

Notifications

Notifications are autonomous events triggered by the internals of the implementation and broadcasted via JSON-RPC to all registered observers. Refer to [Thunder] for information on how to register for a notification.

The following events are provided by the TimeSync plugin:

TimeSync interface events:

Notification Description
timechange Signals a time change

timechange notification

Signals a time change.

Notification Parameters

This notification carries no parameters.

Example

Registration

{
  "jsonrpc": "2.0",
  "id": 42,
  "method": "TimeSync.1.register",
  "params": {
    "event": "timechange",
    "id": "myid"
  }
}

Notification

{
  "jsonrpc": "2.0",
  "method": "myid.timechange"
}

The client ID parameter is passed within the notification designator, i.e. <client-id>.timechange.