notification-events

ServiceNow 的通知事件

事件会在 ServiceNow 中触发通知、脚本和工作流。

事件架构

gs.eventQueue() → Event Queue (sysevent)
    ↓
Event Registry (sysevent_register)
    ↓
Script Actions (sysevent_script_action)
Notifications (sysevent_email_action)

关键表

表	用途
sysevent	事件队列
sysevent_register	事件注册表
sysevent_script_action	脚本操作
sysevent_email_action	电子邮件通知

创建事件（ES5）

注册事件

// Register event in sysevent_register (ES5 ONLY!)
var event = new GlideRecord("sysevent_register")
event.initialize()

event.setValue("event_name", "x_myapp.incident.escalated")
event.setValue("table", "incident")
event.setValue("description", "Fired when an incident is escalated")
event.setValue("fired_by", "Business Rules, Scripts")

// Parameters
event.setValue("parm1", "escalation_level")
event.setValue("parm2", "previous_group")

event.insert()

将事件加入队列

// Queue event from script (ES5 ONLY!)
// gs.eventQueue(event_name, gr, parm1, parm2)

// In a Business Rule
;(function executeRule(current, previous) {
  // Check if escalated
  if (current.escalation.changesTo("1")) {
    gs.eventQueue(
      "x_myapp.incident.escalated",
      current,
      current.getValue("escalation"),
      previous.assignment_group.getDisplayValue(),
    )
  }
})(current, previous)

事件参数

// Access event parameters in script action (ES5 ONLY!)
// event.parm1 = first parameter
// event.parm2 = second parameter

// In Script Action
;(function executeEvent(event) {
  var escalationLevel = event.parm1
  var previousGroup = event.parm2

  var incident = event.getGlideRecord()

  gs.info(
    "Incident " + incident.getValue("number") + " escalated to level " + escalationLevel + " from " + previousGroup,
  )

  // Perform action based on event
  if (escalationLevel === "1") {
    notifyManager(incident)
  } else if (escalationLevel === "2") {
    notifyDirector(incident)
  } else if (escalationLevel === "3") {
    notifyVP(incident)
  }
})(event)

脚本操作（ES5）

创建脚本操作

// Create script action for event (ES5 ONLY!)
var action = new GlideRecord("sysevent_script_action")
action.initialize()

action.setValue("name", "Handle Incident Escalation")
action.setValue("event_name", "x_myapp.incident.escalated")
action.setValue("active", true)

// Condition (optional)
action.setValue("condition", "event.parm1 >= 2")

// Script (ES5 ONLY!)
action.setValue(
  "script",
  "(function executeEvent(event) {\n" +
    "    var incident = event.getGlideRecord();\n" +
    "    var escalationLevel = event.parm1;\n" +
    "    \n" +
    "    // Create escalation task\n" +
    '    var task = new GlideRecord("task");\n' +
    "    task.initialize();\n" +
    "    task.parent = incident.getUniqueValue();\n" +
    '    task.short_description = "Review escalated incident";\n' +
    "    task.assignment_group = getEscalationGroup(escalationLevel);\n" +
    "    task.insert();\n" +
    "    \n" +
    '    gs.info("Created escalation task for " + incident.number);\n' +
    "})(event);",
)

action.insert()

延迟事件

// Queue event with delay (ES5 ONLY!)
// Will be processed after specified time

var delay = new GlideDateTime()
delay.addSeconds(3600) // 1 hour delay

var event = new GlideRecord("sysevent")
event.initialize()
event.setValue("name", "x_myapp.reminder.send")
event.setValue("instance", recordSysId)
event.setValue("table", "incident")
event.setValue("parm1", "first_reminder")
event.setValue("parm2", "")
event.setValue("claimed", false)
event.setValue("process_on", delay)
event.insert()

电子邮件通知（ES5）

创建电子邮件操作

// Create notification for event (ES5 ONLY!)
var notification = new GlideRecord("sysevent_email_action")
notification.initialize()

notification.setValue("name", "Incident Escalation Notification")
notification.setValue("event_name", "x_myapp.incident.escalated")
notification.setValue("active", true)

// Recipients
notification.setValue("recipient_users", "")
notification.setValue("recipient_groups", getGroupSysId("IT Management"))
notification.setValue("send_self", false)

// Use event.parm1 to get escalation manager
notification.setValue("recipient_fields", "assignment_group.manager")

// Email content
notification.setValue("subject", "Incident ${number} Escalated - Level ${event.parm1}")
notification.setValue(
  "message_html",
  "<p>Incident <b>${number}</b> has been escalated.</p>" +
    "<p>Short Description: ${short_description}</p>" +
    "<p>Escalation Level: ${event.parm1}</p>" +
    "<p>Previous Group: ${event.parm2}</p>" +
    '<p><a href="${URI_REF}">View Incident</a></p>',
)

notification.insert()

条件通知

// Notification with advanced condition (ES5 ONLY!)
var notification = new GlideRecord("sysevent_email_action")
notification.initialize()
notification.setValue("name", "VIP Incident Alert")
notification.setValue("event_name", "incident.created")

// Advanced condition script
notification.setValue("advanced_condition", true)
notification.setValue("condition", "current.caller_id.vip == true && current.priority <= 2")

// Send to specific recipients for VIP
notification.setValue("recipient_groups", getGroupSysId("VIP Support"))

notification.insert()

常见事件模式（ES5）

提醒事件

// Schedule reminder events (ES5 ONLY!)
function scheduleReminder(tableName, recordSysId, reminderType, delayMinutes) {
  var eventTime = new GlideDateTime()
  eventTime.addSeconds(delayMinutes * 60)

  var reminder = new GlideRecord("sysevent")
  reminder.initialize()
  reminder.setValue("name", "x_myapp.reminder")
  reminder.setValue("instance", recordSysId)
  reminder.setValue("table", tableName)
  reminder.setValue("parm1", reminderType)
  reminder.setValue("process_on", eventTime)
  reminder.insert()

  return reminder.getUniqueValue()
}

// Cancel scheduled reminder
function cancelReminder(eventSysId) {
  var reminder = new GlideRecord("sysevent")
  if (reminder.get(eventSysId)) {
    reminder.deleteRecord()
    return true
  }
  return false
}

批处理事件

// Queue batch processing (ES5 ONLY!)
// Business Rule: after, insert, u_import_batch

;(function executeRule(current, previous) {
  // Queue processing for each record in batch
  var record = new GlideRecord("u_import_record")
  record.addQuery("batch", current.getUniqueValue())
  record.query()

  while (record.next()) {
    gs.eventQueue("x_myapp.import.process_record", record, current.getUniqueValue(), "")
  }

  // Queue completion check
  var delay = new GlideDateTime()
  delay.addSeconds(300) // Check in 5 minutes

  var event = new GlideRecord("sysevent")
  event.initialize()
  event.setValue("name", "x_myapp.import.check_complete")
  event.setValue("instance", current.getUniqueValue())
  event.setValue("table", "u_import_batch")
  event.setValue("process_on", delay)
  event.insert()
})(current, previous)

状态变更事件

// Generic state change event (ES5 ONLY!)
// Business Rule: after, update

;(function executeRule(current, previous) {
  if (current.state.changes()) {
    gs.eventQueue(
      "x_myapp." + current.getTableName() + ".state_change",
      current,
      previous.getValue("state"),
      current.getValue("state"),
    )
  }
})(current, previous)

事件调试（ES5）

检查事件队列

// Query pending events (ES5 ONLY!)
function getPendingEvents(eventName) {
  var events = []

  var event = new GlideRecord("sysevent")
  event.addQuery("name", eventName)
  event.addQuery("claimed", false)
  event.orderByDesc("sys_created_on")
  event.setLimit(100)
  event.query()

  while (event.next()) {
    events.push({
      sys_id: event.getUniqueValue(),
      name: event.getValue("name"),
      instance: event.getValue("instance"),
      parm1: event.getValue("parm1"),
      parm2: event.getValue("parm2"),
      process_on: event.getValue("process_on"),
      created: event.getValue("sys_created_on"),
    })
  }

  return events
}

MCP 工具集成

可用工具

工具	用途
snow_create_event	将事件加入队列
snow_query_table	查询事件队列
snow_artifact_manage (action='find')	查找事件配置
snow_execute_script	测试事件脚本

工作流示例

// 1. Queue an event
await snow_create_event({
  name: "x_myapp.test.event",
  table: "incident",
  instance: incidentSysId,
  parm1: "test_value",
})

// 2. Check event queue
await snow_query_table({
  table: "sysevent",
  query: "name=x_myapp.test.event^claimed=false",
  fields: "name,instance,parm1,parm2,process_on",
})

// 3. Find script actions
await snow_query_table({
  table: "sysevent_script_action",
  query: "event_nameLIKEx_myapp",
  fields: "name,event_name,active,condition",
})

最佳实践

1. 为事件添加命名空间 - 使用应用前缀（x_myapp.*）
2. 注册事件 - 在 sysevent_register 中记录
3. 使用有意义的名称 - 清晰说明事件用途
4. 参数 - 合理使用 parm1/parm2
5. 条件 - 在处理前进行筛选
6. 异步处理 - 不要阻塞事务
7. 错误处理 - 处理脚本故障
8. 仅使用 ES5 - 不使用现代 JavaScript 语法