Issue Transition in Jira Cloud (ScriptRunner)

Question

I'm having trouble finding simple issue transition code that actually functions in Jira Cloud. I'm trying to set up a ScriptRunner listener for issue updates.

When specific criteria are met (Through my own code logic, not transition validation which I know doesn't work in cloud) I'm trying to transition my issue status. No matter what I do though, I'm still getting the error 'unable to resolve class IssueService'.

Being on cloud, I can't import the proper packages, and I can't find a simple solution anywhere that fits my use case.  How can I actually use any of the IssueService methods, or what alternatives am I supposed to use in Cloud?

Thanks in advance.

Edit: Here's my code after much finagling.

/*Modified from following source:
https://community.atlassian.com/t5/Marketplace-Apps-questions/ScriptRunner-how-to-change-status-of-an-Issue/qaq-p/628842
*/

def currentUser = ComponentAccessor.getJiraAuthenticationContext().getLoggedInUser()
def issueManager = ComponentAccessor.issueManager
def issue = issueManager.getIssueObject(event.issue.key)
IssueService issueService = ComponentAccessor.getIssueService()
def actionId = 10017 //Transition ID
def customFieldManager = ComponentAccessor.getCustomFieldManager()

if (issue.getStatus().name == "Unassigned" && issue.getAssigneeUser() != null) {
    transitionResult = issueService.transition(currentUser, transitionValidationResult)
    //Find docs for transition, replace transitionValidationResult

if (transitionResult.isValid()) {
        log.debug("Transitioned issue $issue through action $actionId")
    }
    else {
log.debug("Transition result is not valid") 
    }
}

Randy_dyxb6i · Answer

Those classes aren't available via Cloud. You'll want to use the supplied binding and hit the API directly or everything else. // use issue.fields to read your issue fields and check that you hit your condition logger.info(issue.fields) // call the transitions endpoint to execute the transition https://developer.atlassian.com/cloud/jira/platform/rest/#api-api-2-issue-issueIdOrKey-transitions-post )
.header("Content-Type", "application/json")
.body([
transition: [
id: transitionID
]
])
.asString()post("/rest/api/2/issue/${issue.key}/transitions"

Jon Hollister · Answer

Updated the top post. I haven't been able to test it at all, because it keeps failing at line 8, unable to resolve class.

IssueService issueService = ComponentAccessor.getIssueService()

Randy_dyxb6i · Answer

Post your script. Doing what you describe is possible with SR on Jira Cloud.