mid-server

MID Server for ServiceNow

MID Server enables ServiceNow to communicate with resources inside your network.

MID Server Architecture

ServiceNow Instance ↓ ECC Queue MID Server ├── Probes (Outbound) │ └── Commands sent TO MID ├── Sensors (Inbound) │ └── Results sent FROM MID └── Script Execution

Key Tables

Table Purpose

ecc_agent

MID Server records

ecc_queue

Input/Output queue

discovery_probes

Probe definitions

discovery_sensors

Sensor definitions

sys_script_execution

Script execution requests

ECC Queue Communication (ES5)

Send Command to MID Server

// Send command via ECC queue (ES5 ONLY!) function sendMIDCommand(midServerName, command, parameters) { var mid = getMIDServer(midServerName) if (!mid) { gs.error("MID Server not found: " + midServerName) return null }

var ecc = new GlideRecord("ecc_queue") ecc.initialize()

// ECC Queue settings ecc.setValue("agent", mid.getUniqueValue()) ecc.setValue("topic", "Command") ecc.setValue("name", command) ecc.setValue("source", "CustomScript")

// Parameters as payload ecc.setValue("payload", buildPayload(parameters))

// Direction: output = to MID, input = from MID ecc.setValue("queue", "output")

// State ecc.setValue("state", "ready")

return ecc.insert() }

function getMIDServer(name) { var mid = new GlideRecord("ecc_agent") mid.addQuery("name", name) mid.addQuery("status", "Up") mid.query() if (mid.next()) { return mid } return null }

function buildPayload(params) { var xml = '<?xml version="1.0" encoding="UTF-8"?>' xml += "<parameters>" for (var key in params) { if (params.hasOwnProperty(key)) { xml += '<parameter name="' + key + '">' xml += "<value>" + escapeXML(params[key]) + "</value>" xml += "</parameter>" } } xml += "</parameters>" return xml }

function escapeXML(str) { return str .replace(/&/g, "&") .replace(/</g, "<") .replace(/>/g, ">") .replace(/"/g, """) .replace(/'/g, "'") }

Monitor ECC Response

// Wait for ECC queue response (ES5 ONLY!) function waitForECCResponse(eccSysId, timeoutSeconds) { var startTime = new Date().getTime() var timeout = timeoutSeconds * 1000

while (true) { // Check for response var response = new GlideRecord("ecc_queue") response.addQuery("response_to", eccSysId) response.addQuery("queue", "input") response.query()

if (response.next()) {
  return {
    success: response.getValue("state") === "processed",
    payload: response.getValue("payload"),
    error: response.getValue("error_string"),
  }
}

// Check timeout
if (new Date().getTime() - startTime > timeout) {
  return {
    success: false,
    error: "Timeout waiting for MID response",
  }
}

// Wait before retry
gs.sleep(1000)

} }

MID Server Scripts (ES5)

Execute Script on MID

// Execute JavaScript on MID Server (ES5 ONLY!) function executeMIDScript(midServerName, script) { var mid = getMIDServer(midServerName) if (!mid) { return { success: false, error: "MID Server not found" } }

var ecc = new GlideRecord("ecc_queue") ecc.initialize() ecc.setValue("agent", mid.getUniqueValue()) ecc.setValue("topic", "JSProbe") ecc.setValue("name", "Custom Script Execution")

// Script payload var payload = '<?xml version="1.0" encoding="UTF-8"?>' payload += "<parameters>" payload += '<parameter name="script"><value><![CDATA[' + script + "]]></value></parameter>" payload += "</parameters>"

ecc.setValue("payload", payload) ecc.setValue("queue", "output") ecc.setValue("state", "ready")

var eccSysId = ecc.insert()

return { success: true, ecc_sys_id: eccSysId, } }

// Example: Check disk space on remote server var diskCheckScript = [ "var output = {};", "try {", ' var cmd = "df -h /";', " var result = Packages.com.service_now.mid.probe.tpcon.OperatingSystemCommand.execute(cmd);", " output.disk_info = result.getOutput();", " output.success = true;", "} catch (e) {", " output.success = false;", " output.error = e.message;", "}", "output;", ].join("\n")

Custom Probes (ES5)

Create Probe

// Create custom probe (ES5 ONLY!) var probe = new GlideRecord("discovery_probes") probe.initialize()

probe.setValue("name", "Custom Application Status") probe.setValue("short_description", "Check custom application status") probe.setValue("active", true)

// Probe type probe.setValue("mid_type", "probe")

// Trigger type probe.setValue("triggered_by", "on_demand")

// Probe script (runs on MID Server - ES5/Rhino!) probe.setValue( "script", "var output = {};\n" + "\n" + "// Get parameters\n" + 'var host = probe.getParameter("host");\n' + 'var port = probe.getParameter("port");\n' + "\n" + "try {\n" + " // Execute health check\n" + ' var url = "http://" + host + ":" + port + "/health";\n' + " var conn = new java.net.URL(url).openConnection();\n" + ' conn.setRequestMethod("GET");\n' + " conn.setConnectTimeout(5000);\n" + " conn.setReadTimeout(5000);\n" + " \n" + " var responseCode = conn.getResponseCode();\n" + ' output.status = (responseCode === 200) ? "healthy" : "unhealthy";\n' + " output.response_code = responseCode;\n" + " output.success = true;\n" + "} catch (e) {\n" + ' output.status = "unreachable";\n' + " output.error = e.message;\n" + " output.success = false;\n" + "}\n" + "\n" + "output;", )

probe.insert()

Create Sensor

// Create sensor to process probe results (ES5 ONLY!) var sensor = new GlideRecord("discovery_sensors") sensor.initialize()

sensor.setValue("name", "Process Application Status") sensor.setValue("short_description", "Process custom application status results") sensor.setValue("active", true)

// Link to probe sensor.setValue("triggered_by", probeSysId)

// Sensor script (runs on ServiceNow instance - ES5!) sensor.setValue( "script", "(function process(result, source) {\n" + " var output = JSON.parse(result.output);\n" + " \n" + " // Find or create application CI\n" + ' var appCI = new GlideRecord("cmdb_ci_appl");\n' + ' appCI.addQuery("name", source.getParameter("app_name"));\n' + " appCI.query();\n" + " \n" + " if (!appCI.next()) {\n" + " appCI.initialize();\n" + ' appCI.name = source.getParameter("app_name");\n' + " appCI.insert();\n" + " }\n" + " \n" + " // Update status\n" + " appCI.u_health_status = output.status;\n" + " appCI.u_last_health_check = new GlideDateTime();\n" + " appCI.update();\n" + " \n" + " // Create event if unhealthy\n" + ' if (output.status !== "healthy") {\n' + " createHealthAlert(appCI, output);\n" + " }\n" + "})(result, source);", )

sensor.insert()

Orchestration (ES5)

Remote PowerShell

// Execute PowerShell on Windows server (ES5 ONLY!) function executeRemotePowerShell(midServerName, targetHost, script, credential) { var payload = [ '<?xml version="1.0" encoding="UTF-8"?>', "<parameters>", ' <parameter name="host"><value>' + targetHost + "</value></parameter>", ' <parameter name="credential_id"><value>' + credential + "</value></parameter>", ' <parameter name="script"><value><![CDATA[' + script + "]]></value></parameter>", "</parameters>", ].join("\n")

var mid = getMIDServer(midServerName) if (!mid) { return { success: false, error: "MID Server not found" } }

var ecc = new GlideRecord("ecc_queue") ecc.initialize() ecc.setValue("agent", mid.getUniqueValue()) ecc.setValue("topic", "PowerShell") ecc.setValue("name", "Remote PowerShell Execution") ecc.setValue("payload", payload) ecc.setValue("queue", "output") ecc.setValue("state", "ready")

return { success: true, ecc_sys_id: ecc.insert(), } }

Remote SSH

// Execute SSH command (ES5 ONLY!) function executeRemoteSSH(midServerName, targetHost, command, credential) { var payload = [ '<?xml version="1.0" encoding="UTF-8"?>', "<parameters>", ' <parameter name="host"><value>' + targetHost + "</value></parameter>", ' <parameter name="credential_id"><value>' + credential + "</value></parameter>", ' <parameter name="command"><value>' + escapeXML(command) + "</value></parameter>", "</parameters>", ].join("\n")

var mid = getMIDServer(midServerName) if (!mid) { return { success: false, error: "MID Server not found" } }

var ecc = new GlideRecord("ecc_queue") ecc.initialize() ecc.setValue("agent", mid.getUniqueValue()) ecc.setValue("topic", "SSHCommand") ecc.setValue("name", "Remote SSH Execution") ecc.setValue("payload", payload) ecc.setValue("queue", "output") ecc.setValue("state", "ready")

return { success: true, ecc_sys_id: ecc.insert(), } }

MID Server Monitoring (ES5)

Check MID Status

// Get MID Server status (ES5 ONLY!) function getMIDServerStatus() { var servers = []

var mid = new GlideRecord("ecc_agent") mid.addQuery("status", "!=", "Decommissioned") mid.query()

while (mid.next()) { servers.push({ name: mid.getValue("name"), status: mid.getValue("status"), ip: mid.getValue("ip_address"), version: mid.getValue("version"), validated: mid.getValue("validated"), last_refreshed: mid.getValue("last_refreshed"), host_name: mid.getValue("host_name"), }) }

return servers }

MCP Tool Integration

Available Tools

Tool Purpose

snow_query_table

Query MID and ECC tables

snow_find_artifact

Find probes/sensors

snow_execute_script_with_output

Test MID scripts

Example Workflow

// 1. Check MID Server status await snow_query_table({ table: "ecc_agent", query: "status=Up", fields: "name,ip_address,version,last_refreshed", })

// 2. Query ECC queue await snow_query_table({ table: "ecc_queue", query: "queue=output^state=ready", fields: "agent,topic,name,state,sys_created_on", })

// 3. Find probes await snow_query_table({ table: "discovery_probes", query: "active=true", fields: "name,short_description,mid_type", })

Best Practices

Credentials - Never hardcode in scripts
Error Handling - Handle network failures
Timeouts - Set appropriate timeouts
Logging - Log for troubleshooting
Security - Limit MID access
Monitoring - Track MID health
Load Balancing - Multiple MIDs for HA
ES5 Only - No modern JavaScript syntax

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