arthas/arthas-tutorials-en/case/http-api/one-time-command.md

Similar to executing batch commands, the one-time commands are executed synchronously. No need to create a session, no need to set the sessionId{{}} option.

{
  "action": "exec",
  "command": "<Arthas command line>"
}

For example, get the Arthas version number:

curl -Ss -XPOST http://localhost:8563/api -d ' { "action":"exec", "command":"version" } ' | json_pp{{execute T3}}

The response is as follows:

{
  "state": "SUCCEEDED",
  "sessionId": "ee3bc004-4586-43de-bac0-b69d6db7a869",
  "body": {
    "results": [
      {
        "type": "version",
        "version": "3.3.7",
        "jobId": 5
      },
      {
        "jobId": 5,
        "statusCode": 0,
        "type": "status"
      }
    ],
    "timeExpired": false,
    "command": "version",
    "jobStatus": "TERMINATED",
    "jobId": 5
  }
}

Response data format description:

• state{{}} : Request processing status, refer to the description of "Response Status".
• sessionId {{}} : Arthas session ID, one-time command to automatically create and destroy temporary sessions.
• body.jobId{{}} : The job ID of the command, all output results of the same job are the same jobId.
• body.jobStatus{{}} : The job status of the command.
• body.timeExpired{{}} : Whether the job execution timed out.
• body/results{{}} : Command execution results.

Command result format description

[
  {
    "type": "version",
    "version": "3.3.7",
    "jobId": 5
  },
  {
    "jobId": 5,
    "statusCode": 0,
    "type": "status"
  }
]

• type{{}} : The command result type, except for the special ones such as status{{}} , the others remain the same as the Arthas command name. Please refer to the section "Special command results".
• jobId{{}} : The job ID of the command.
• Other fields are the data of each different command.

Note: You can also use a one-time command to execute continuous output commands such as watch/trace, but you can't interrupt the command execution, and there may be hang up for a long time. Please refer to the example in the "Make watch command output a map object" section.

Please try to deal with it in the following way:

• Set a reasonable execTimeout{{}} to forcibly interrupt the command execution after the timeout period is reached to avoid a long hang.
• Use the -n{{}} parameter to specify a smaller number of executions.
• Ensure the methods of the command matched can be successfully hit and the condition-express{{}} is written correctly. If the watch/trace{{}} does not hit, even if -n 1{{}} is specified, it will hang and wait until the execution timeout.