Monitor API

Version: 1.0.0

Status:

Monitor interface for Thunder framework.

Introduction

Scope

This document describes purpose and functionality of the Monitor interface (version 1.0.0). It includes detailed specification about its 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

Monitor JSON-RPC interface.

Methods

The following methods are provided by the Monitor interface:

Monitor interface methods:

Method	Description
restartlimits	Sets new restart limits for a service
resetstats	Resets memory and process statistics for a single service watched by the Monitor

restartlimits ^method

Sets new restart limits for a service.

Parameters

Name	Type	M/O	Description
params	object	mandatory	...
params.callsign	string	mandatory	The callsign of a service to reset measurements snapshot of
params.restart	object	mandatory	Restart limits for failures applying to the service
params.restart.limit	integer	mandatory	Maximum number or restarts to be attempted
params.restart.window	integer	mandatory	Time period (in seconds) within which failures must happen for the limit to be considered crossed

Result

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

Example

Request

{
  "jsonrpc": "2.0",
  "id": 42,
  "method": "<callsign>.1.restartlimits",
  "params": {
    "callsign": "WebServer",
    "restart": {
      "limit": 3,
      "window": 60
    }
  }
}

Response

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

resetstats ^method

Resets memory and process statistics for a single service watched by the Monitor.

Parameters

Name	Type	M/O	Description
params	object	mandatory	...
params.callsign	string	mandatory	The callsign of a service to reset statistics of

Result

Name	Type	M/O	Description
result	object	mandatory	Measurements for the service before reset
result.measurements	object	mandatory	Measurements for the service
result.measurements.resident	object	mandatory	Resident memory measurement
result.measurements.resident.min	integer	mandatory	Minimal value measured
result.measurements.resident.max	integer	mandatory	Maximal value measured
result.measurements.resident.average	integer	mandatory	Average of all measurements
result.measurements.resident.last	integer	mandatory	Last measured value
result.measurements.allocated	object	mandatory	Allocated memory measurement
result.measurements.allocated.min	integer	mandatory	Minimal value measured
result.measurements.allocated.max	integer	mandatory	Maximal value measured
result.measurements.allocated.average	integer	mandatory	Average of all measurements
result.measurements.allocated.last	integer	mandatory	Last measured value
result.measurements.shared	object	mandatory	Shared memory measurement
result.measurements.shared.min	integer	mandatory	Minimal value measured
result.measurements.shared.max	integer	mandatory	Maximal value measured
result.measurements.shared.average	integer	mandatory	Average of all measurements
result.measurements.shared.last	integer	mandatory	Last measured value
result.measurements.process	object	mandatory	Processes measurement
result.measurements.process.min	integer	mandatory	Minimal value measured
result.measurements.process.max	integer	mandatory	Maximal value measured
result.measurements.process.average	integer	mandatory	Average of all measurements
result.measurements.process.last	integer	mandatory	Last measured value
result.measurements.operational	boolean	mandatory	Whether the service is up and running
result.measurements.count	integer	mandatory	Number of measurements
result.observable	string	mandatory	A callsign of the watched service
result.restart	object	mandatory	Restart limits for failures applying to the service
result.restart.limit	integer	mandatory	Maximum number or restarts to be attempted
result.restart.window	integer	mandatory	Time period (in seconds) within which failures must happen for the limit to be considered crossed

Example

Request

{
  "jsonrpc": "2.0",
  "id": 42,
  "method": "<callsign>.1.resetstats",
  "params": {
    "callsign": "WebServer"
  }
}

Response

{
  "jsonrpc": "2.0",
  "id": 42,
  "result": {
    "measurements": {
      "resident": {
        "min": 0,
        "max": 100,
        "average": 50,
        "last": 100
      },
      "allocated": {
        "min": 0,
        "max": 100,
        "average": 50,
        "last": 100
      },
      "shared": {
        "min": 0,
        "max": 100,
        "average": 50,
        "last": 100
      },
      "process": {
        "min": 0,
        "max": 100,
        "average": 50,
        "last": 100
      },
      "operational": true,
      "count": 100
    },
    "observable": "callsign",
    "restart": {
      "limit": 3,
      "window": 60
    }
  }
}

Properties

The following properties are provided by the Monitor interface:

Monitor interface properties:

Property	R/W	Description
status	read-only	Service statistics

status ^property

Provides access to the service statistics.

This property is read-only.

The callsign parameter shall be passed as the index to the property, i.e. status@<callsign>.

Index

Name	Type	M/O	Description
callsign	string	mandatory	If omitted then all observed objects will be returned on read

Value

Name	Type	M/O	Description
(property)	array	mandatory	Service statistics
(property)[#]	object	mandatory	...
(property)[#].measurements	object	mandatory	Measurements for the service
(property)[#].measurements.resident	object	mandatory	Resident memory measurement
(property)[#].measurements.resident.min	integer	mandatory	Minimal value measured
(property)[#].measurements.resident.max	integer	mandatory	Maximal value measured
(property)[#].measurements.resident.average	integer	mandatory	Average of all measurements
(property)[#].measurements.resident.last	integer	mandatory	Last measured value
(property)[#].measurements.allocated	object	mandatory	Allocated memory measurement
(property)[#].measurements.allocated.min	integer	mandatory	Minimal value measured
(property)[#].measurements.allocated.max	integer	mandatory	Maximal value measured
(property)[#].measurements.allocated.average	integer	mandatory	Average of all measurements
(property)[#].measurements.allocated.last	integer	mandatory	Last measured value
(property)[#].measurements.shared	object	mandatory	Shared memory measurement
(property)[#].measurements.shared.min	integer	mandatory	Minimal value measured
(property)[#].measurements.shared.max	integer	mandatory	Maximal value measured
(property)[#].measurements.shared.average	integer	mandatory	Average of all measurements
(property)[#].measurements.shared.last	integer	mandatory	Last measured value
(property)[#].measurements.process	object	mandatory	Processes measurement
(property)[#].measurements.process.min	integer	mandatory	Minimal value measured
(property)[#].measurements.process.max	integer	mandatory	Maximal value measured
(property)[#].measurements.process.average	integer	mandatory	Average of all measurements
(property)[#].measurements.process.last	integer	mandatory	Last measured value
(property)[#].measurements.operational	boolean	mandatory	Whether the service is up and running
(property)[#].measurements.count	integer	mandatory	Number of measurements
(property)[#].observable	string	mandatory	A callsign of the watched service
(property)[#].restart	object	mandatory	Restart limits for failures applying to the service
(property)[#].restart.limit	integer	mandatory	Maximum number or restarts to be attempted
(property)[#].restart.window	integer	mandatory	Time period (in seconds) within which failures must happen for the limit to be considered crossed

Example

Get Request

{
  "jsonrpc": "2.0",
  "id": 42,
  "method": "<callsign>.1.status@WebServer"
}

Get Response

{
  "jsonrpc": "2.0",
  "id": 42,
  "result": [
    {
      "measurements": {
        "resident": {
          "min": 0,
          "max": 100,
          "average": 50,
          "last": 100
        },
        "allocated": {
          "min": 0,
          "max": 100,
          "average": 50,
          "last": 100
        },
        "shared": {
          "min": 0,
          "max": 100,
          "average": 50,
          "last": 100
        },
        "process": {
          "min": 0,
          "max": 100,
          "average": 50,
          "last": 100
        },
        "operational": true,
        "count": 100
      },
      "observable": "callsign",
      "restart": {
        "limit": 3,
        "window": 60
      }
    }
  ]
}

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 Monitor interface:

Monitor interface events:

Notification	Description
action	Signals an action taken by the Monitor

action ^notification

Signals an action taken by the Monitor.

Notification Parameters

Name	Type	M/O	Description
params	object	mandatory	...
params.callsign	string	mandatory	Callsign of the service the Monitor acted upon
params.action	string	mandatory	The action executed by the Monitor on a service. One of: "Activate", "Deactivate", "StoppedRestarting"
params.reason	string	mandatory	A message describing the reason the action was taken

Example

Registration

{
  "jsonrpc": "2.0",
  "id": 42,
  "method": "<callsign>.1.register",
  "params": {
    "event": "action",
    "id": "myid"
  }
}

Notification

{
  "jsonrpc": "2.0",
  "method": "myid.action",
  "params": {
    "callsign": "WebServer",
    "action": "Deactivate",
    "reason": "EXCEEDED_MEMORY"
  }
}

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

Monitor API

Table of Contents

Introduction

Scope

Case Sensitivity

Acronyms, Abbreviations and Terms

References

Description

Methods

restartlimits method

Parameters

Result

Example

Request

Response

resetstats method

Parameters

Result

Example

Request

Response

Properties

status property

Index

Value

Example

Get Request

Get Response

Notifications

action notification

Notification Parameters

Example

Registration

Notification

restartlimits ^method

resetstats ^method

status ^property

action ^notification