JobScheduler Universal Agent - REST Web Service

Universal Agent REST Web Service

The Universal Agent comes with a REST web service that allows it to be controlled from the command line. The service supports the following operations:

• sending commands and
• showing information.

Commands can be sent to an Agent:

• via any client application that sends the command with an HTTP request (JSON)
• via the start script of the Agent.
  The start script makes use of a Java class that implements the HTTP client.

Start Script Status Information

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The information is returned in JSON format.

If the Agent is not available, an exit status is returned accordingly.

The web service overview is called using  jobscheduler_agent.sh status .

Web Service Status Information

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The Universal Agent provides status information via web services.

URI Syntax

All API URIs start with an optional prefix (if set on starting the Agent with the command line option -uri-prefix= set) and the /jobscheduler/agent/api character string.

• General status information is provided by:
  • /jobscheduler/agent/api
• General status information is also provided by:
  
  • /jobscheduler/agent/api/overview
• Information about the Agent tasks running is provided by the web service:
  • /jobscheduler/agent/api/task
• Information about the active command is provided by the web service:
  
  • /jobscheduler/agent/api/tunnel
• Information about the active command is provided by the web service:
  
  • /jobscheduler/agent/api/tunnel (without an end forward slash)
• A list of tunnels is provided by the web service:
  
  • /jobscheduler/agent/api/tunnel/ (with an end forward slash)
• A summary of the commands running is provided by the web service:
  
  • /jobscheduler/agent/api/command (without an end forward slash)
• A list of the commands running is provided by the web service:
  
  • /jobscheduler/agent/api/command/ (with an end forward slash)

Note

These services are read only (HTTP verb GET). Changes are made using the command service (api/command). (The only command is terminate).

The following web services are addressed with the verb POST:

• /jobscheduler/agent/api/task/command
• /jobscheduler/agent/api/tunnel/id

Status Information Examples

totalTaskCount: 0
isTerminating: false
system:
  hostname: docker-agent
  mxBeans:
    operatingSystem:
      processCpuLoad: 9.71859949958501E-7
      availableProcessors: 8
      freePhysicalMemorySize: 1791545344
      systemCpuLoad: 0.00774040220626055
      committedVirtualMemorySize: 4809150464
      totalPhysicalMemorySize: 4897579008
currentTaskCount: 0
java:
  systemProperties:
    java.vendor: Azul Systems, Inc.
    os.arch: amd64
    os.version: 3.10.0-229.7.2.el7.x86_64
    os.name: Linux
    java.version: 1.8.0_25
version: 1.10.0-xx
startedAt: '2015-08-19T15:21:42.423Z'

tasks:
- id: 4-259101459
  tunnelId: '4'
  controllerAddress: 127.0.0.1:9338
  startedAt: '2015-08-19T13:11:18.239Z'
- id: 2-15899022
  tunnelId: '2'
  controllerAddress: 127.0.0.1:9338
  startedAt: '2015-08-19T13:11:18.239Z'
- id: 3-707059672
  tunnelId: '3'
  controllerAddress: 127.0.0.1:9338
  startedAt: '2015-08-19T13:11:18.239Z'

Termination via Web Service

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The JobScheduler Universal Agent is terminated

• by use of the start script, e.g.
  
  • ./jobscheduler_agent.sh stop
• by calling the Agent web service URL for commands with a JSON command
  
  • /jobscheduler/agent/api/command

JSON commands to terminate the Agent are sent by an HTTP POST request and include:

• abort immediately:
  
  • the Agent will kill all running tasks and will terminate immediately
  • the client sends:
    • { "$TYPE": "AbortImmediately" }
  • this corresponds to the XML command that is used for a Master:
    • <modify_spooler cmd='abort_immediately'/>
• terminate:
  
  • the Agent will not start new tasks, existing tasks can continue and the Agent will terminate after all tasks have completed
  • optionally a SIGTERM can be sent to the tasks
  • the client sends:
    • { "$TYPE": "Terminate", "sigtermProcesses": false }
  • this corresponds to the XML command that is used for a Master:
    • <modify_spooler cmd='terminate'/>
• terminate with timeout:
  • the Agent sends all tasks a SIGTERM command and will wait for the specified timeout.
    Should any task not terminate within the specified timeout then it will be killed with a SIGKILL signal.
  • the client sends:
    • { "$TYPE": "Terminate", "sigtermProcesses": false, "sigkillProcessesAfter": 15 }
  • this corresponds to the XML command that is used for a Master:
    • <modify_spooler cmd='terminate' timeout='15'/>

References

See also

• How to implement a client for REST web services

Change Management References