Collect Citrix Monitor Service logs

Supported in:

Google secops SIEM

This document explains how to ingest Citrix Monitor Service logs to Google Security Operations using Google Cloud Storage. The parser transforms raw JSON formatted logs into a structured format conforming to the Google SecOps UDM. It extracts relevant fields from the raw log, maps them to corresponding UDM fields, and enriches the data with additional context like user information, machine details, and network activity.

Before you begin

Make sure you have the following prerequisites:

A Google SecOps instance
A GCP project with Cloud Storage API enabled
Permissions to create and manage GCS buckets
Permissions to manage IAM policies on GCS buckets
Permissions to create Cloud Run functions, Pub/Sub topics, and Cloud Scheduler jobs
Permissions to create service accounts and manage IAM roles
Privileged access to Citrix Cloud tenant
Citrix Cloud API credentials (Client ID, Client Secret, Customer ID)

Collect Citrix Monitor Service prerequisites

Sign in to the Citrix Cloud Console.
Go to Identity and Access Management > API Access.
Click Create Client.
Copy and save in a secure location the following details:
- Client ID
- Client Secret
- Customer ID (visible in Citrix Cloud console)
- API Base URL:
  - US/EU/AP-S: https://api.cloud.com
  - Japan: https://api.citrixcloud.jp
Note: Use the endpoint based on the geographical region you selected while accessing the Citrix Monitor Service data for DaaS: US/EU/AP-S region uses https://api.cloud.com/monitorodata, Japan region uses https://api.citrixcloud.jp/monitorodata.

Create Google Cloud Storage bucket

Go to the Google Cloud Console.
Select your project or create a new one.
In the navigation menu, go to Cloud Storage > Buckets.
Click Create bucket.

Provide the following configuration details:

Setting	Value
Name your bucket	Enter a globally unique name (for example, `citrix-monitor-logs`)
Location type	Choose based on your needs (Region, Dual-region, Multi-region)
Location	Select the location (for example, `us-central1`)
Storage class	Standard (recommended for frequently accessed logs)
Access control	Uniform (recommended)
Protection tools	Optional: Enable object versioning or retention policy

Click Create.

Create service account for Cloud Run function

The Cloud Run function needs a service account with permissions to write to GCS bucket.

Create service account

In the GCP Console, go to IAM & Admin > Service Accounts.
Click Create Service Account.
Provide the following configuration details:
- Service account name: Enter citrix-monitor-collector-sa.
- Service account description: Enter Service account for Cloud Run function to collect Citrix Monitor Service logs.
Click Create and Continue.
In the Grant this service account access to project section:
1. Click Select a role.
2. Search for and select Storage Object Admin.
3. Click + Add another role.
4. Search for and select Cloud Run Invoker.
5. Click + Add another role.
6. Search for and select Cloud Functions Invoker.
Click Continue.
Click Done.

These roles are required for:

Storage Object Admin: Write logs to GCS bucket and manage state files
Cloud Run Invoker: Allow Pub/Sub to invoke the function
Cloud Functions Invoker: Allow function invocation

Grant IAM permissions on GCS bucket

Grant the service account write permissions on the GCS bucket:

Go to Cloud Storage > Buckets.
Click your bucket name.
Go to the Permissions tab.
Click Grant access.
Provide the following configuration details:
- Add principals: Enter the service account email (citrix-monitor-collector-sa@PROJECT_ID.iam.gserviceaccount.com).
- Assign roles: Select Storage Object Admin.
Click Save.

Create Pub/Sub topic

Create a Pub/Sub topic that Cloud Scheduler will publish to and the Cloud Run function will subscribe to.

In the GCP Console, go to Pub/Sub > Topics.
Click Create topic.
Provide the following configuration details:
- Topic ID: Enter citrix-monitor-trigger.
- Leave other settings as default.
Click Create.

Create Cloud Run function to collect logs

The Cloud Run function is triggered by Pub/Sub messages from Cloud Scheduler to fetch logs from Citrix Monitor Service API and writes them to GCS.

In the GCP Console, go to Cloud Run.
Click Create service.
Select Function (use an inline editor to create a function).
In the Configure section, provide the following configuration details:

Setting Value

Service name citrix-monitor-collector

Region Select region matching your GCS bucket (for example, us-central1)

Runtime Select Python 3.12 or later
In the Trigger (optional) section:
1. Click + Add trigger.
2. Select Cloud Pub/Sub.
3. In Select a Cloud Pub/Sub topic, choose the topic (citrix-monitor-trigger).
4. Click Save.
In the Authentication section:
1. Select Require authentication.
2. Check Identity and Access Management (IAM).
Note: Pub/Sub automatically handles authentication when invoking the function.
Scroll down and expand Containers, Networking, Security.
Go to the Security tab:
- Service account: Select the service account (citrix-monitor-collector-sa).

Setting	Value
Service name	`citrix-monitor-collector`
Region	Select region matching your GCS bucket (for example, `us-central1`)
Runtime	Select Python 3.12 or later

Go to the Containers tab:

Click Variables & Secrets.
Click + Add variable for each environment variable:

Variable Name	Example Value
`GCS_BUCKET`	`citrix-monitor-logs`
`GCS_PREFIX`	`citrix_monitor`
`STATE_KEY`	`citrix_monitor/state.json`
`CITRIX_CLIENT_ID`	`your-client-id`
`CITRIX_CLIENT_SECRET`	`your-client-secret`
`CITRIX_CUSTOMER_ID`	`your-customer-id`
`API_BASE`	`https://api.cloud.com`
`ENTITIES`	`Machines,Sessions,Connections,Applications,Users`
`PAGE_SIZE`	`1000`
`LOOKBACK_MINUTES`	`75`
`USE_TIME_FILTER`	`true`

Scroll down in the Variables & Secrets tab to Requests:
- Request timeout: Enter 600 seconds (10 minutes).
Go to the Settings tab in Containers:
- In the Resources section:
  - Memory: Select 512 MiB or higher.
  - CPU: Select 1.
- Click Done.
Scroll to Execution environment:
- Select Default (recommended).
In the Revision scaling section:
- Minimum number of instances: Enter 0.
- Maximum number of instances: Enter 100 (or adjust based on expected load).
Click Create.
Wait for the service to be created (1-2 minutes).
After the service is created, the inline code editor opens automatically.

Add function code

Enter main in Function entry point

In the inline code editor, create two files:

First file: main.py:

import functions_framework
from google.cloud import storage
import json
import os
import urllib3
from datetime import datetime, timedelta, timezone
import uuid

# Citrix Cloud OAuth2 endpoint template
TOKEN_URL_TMPL = "{api_base}/cctrustoauth2/{customerid}/tokens/clients"
DEFAULT_API_BASE = "https://api.cloud.com"
MONITOR_BASE_PATH = "/monitorodata"

# Initialize HTTP client
http = urllib3.PoolManager()

# Initialize Storage client
storage_client = storage.Client()

def http_post_form(url, data_dict):
    """POST form data to get authentication token."""
    encoded_data = urllib3.request.urlencode(data_dict)
    response = http.request(
        'POST',
        url,
        body=encoded_data,
        headers={
            'Accept': 'application/json',
            'Content-Type': 'application/x-www-form-urlencoded'
        }
    )
    return json.loads(response.data.decode('utf-8'))

def http_get_json(url, headers):
    """GET JSON data from API endpoint."""
    response = http.request('GET', url, headers=headers)
    return json.loads(response.data.decode('utf-8'))

def get_citrix_token(api_base, customer_id, client_id, client_secret):
    """Get Citrix Cloud authentication token."""
    url = TOKEN_URL_TMPL.format(
        api_base=api_base.rstrip('/'),
        customerid=customer_id
    )
    payload = {
        'grant_type': 'client_credentials',
        'client_id': client_id,
        'client_secret': client_secret
    }
    response = http_post_form(url, payload)
    return response['access_token']

def build_entity_url(api_base, entity, filter_query=None, top=None):
    """Build OData URL with optional filter and pagination."""
    base = api_base.rstrip('/') + MONITOR_BASE_PATH + '/' + entity
    params = []
    if filter_query:
        # Encode filter query with safe characters for OData
        encoded_filter = urllib3.request.urlencode({'$filter': filter_query})[9:]  # Remove '$filter='
        params.append('$filter=' + encoded_filter)
    if top:
        params.append('$top=' + str(top))
    return base + ('?' + '&'.join(params) if params else '')

def fetch_entity_rows(entity, start_iso=None, end_iso=None, page_size=1000, headers=None, api_base=DEFAULT_API_BASE):
    """Fetch entity data with optional time filtering and pagination."""
    first_url = None
    if start_iso and end_iso:
        filter_query = f"(ModifiedDate ge {start_iso} and ModifiedDate lt {end_iso})"
        first_url = build_entity_url(api_base, entity, filter_query, page_size)
    else:
        first_url = build_entity_url(api_base, entity, None, page_size)

    url = first_url
    while url:
        try:
            data = http_get_json(url, headers)
            items = data.get('value', [])
            for item in items:
                yield item
            url = data.get('@odata.nextLink')
        except Exception as e:
            # If ModifiedDate filtering fails, fall back to unfiltered query
            if 'Bad Request' in str(e) and start_iso and end_iso:
                print(f"ModifiedDate filter not supported for {entity}, falling back to unfiltered query")
                url = build_entity_url(api_base, entity, None, page_size)
                continue
            else:
                raise

def load_state(bucket, key):
    """Read the last processed timestamp from GCS state file."""
    try:
        blob = bucket.blob(key)
        if blob.exists():
            content = blob.download_as_text()
            state = json.loads(content)
            timestamp_str = state.get('last_hour_utc')
            if timestamp_str:
                return datetime.fromisoformat(timestamp_str.replace('Z', '+00:00')).replace(tzinfo=None)
    except Exception as e:
        print(f"Warning: Could not load state: {str(e)}")
    return None

def save_state(bucket, key, dt_utc):
    """Write the current processed timestamp to GCS state file."""
    state = {'last_hour_utc': dt_utc.isoformat() + 'Z'}
    blob = bucket.blob(key)
    blob.upload_from_string(
        json.dumps(state, separators=(',', ':')),
        content_type='application/json'
    )

def write_ndjson_to_gcs(bucket, key, rows):
    """Write rows as NDJSON to GCS."""
    body_lines = []
    for row in rows:
        json_line = json.dumps(row, separators=(',', ':'), ensure_ascii=False)
        body_lines.append(json_line)
    body = '\n'.join(body_lines) + '\n'
    blob = bucket.blob(key)
    blob.upload_from_string(body, content_type='application/x-ndjson')

@functions_framework.cloud_event
def main(cloud_event):
    """
    Cloud Run function triggered by Pub/Sub to fetch Citrix Monitor Service logs and write to GCS.

    Args:
        cloud_event: CloudEvent object containing Pub/Sub message
    """

    # Get environment variables
    bucket_name = os.environ.get('GCS_BUCKET')
    prefix = os.environ.get('GCS_PREFIX', 'citrix_monitor').strip('/')
    state_key = os.environ.get('STATE_KEY') or f"{prefix}/state.json"
    customer_id = os.environ.get('CITRIX_CUSTOMER_ID')
    client_id = os.environ.get('CITRIX_CLIENT_ID')
    client_secret = os.environ.get('CITRIX_CLIENT_SECRET')
    api_base = os.environ.get('API_BASE', DEFAULT_API_BASE)
    entities = [e.strip() for e in os.environ.get('ENTITIES', 'Machines,Sessions,Connections,Applications,Users').split(',') if e.strip()]
    page_size = int(os.environ.get('PAGE_SIZE', '1000'))
    lookback_minutes = int(os.environ.get('LOOKBACK_MINUTES', '75'))
    use_time_filter = os.environ.get('USE_TIME_FILTER', 'true').lower() == 'true'

    if not all([bucket_name, customer_id, client_id, client_secret]):
        print('Error: Missing required environment variables')
        return

    try:
        # Get GCS bucket
        bucket = storage_client.bucket(bucket_name)

        # Time window calculation
        now = datetime.utcnow()
        fallback_hour = (now - timedelta(minutes=lookback_minutes)).replace(minute=0, second=0, microsecond=0)
        last_processed = load_state(bucket, state_key)
        target_hour = (last_processed + timedelta(hours=1)) if last_processed else fallback_hour
        start_iso = target_hour.isoformat() + 'Z'
        end_iso = (target_hour + timedelta(hours=1)).isoformat() + 'Z'

        # Authentication
        token = get_citrix_token(api_base, customer_id, client_id, client_secret)
        headers = {
            'Authorization': f'CWSAuth bearer={token}',
            'Citrix-CustomerId': customer_id,
            'Accept': 'application/json',
            'Accept-Encoding': 'gzip, deflate, br',
            'User-Agent': 'citrix-monitor-gcs-collector/1.0'
        }

        total_records = 0

        # Process each entity type
        for entity in entities:
            rows_batch = []
            try:
                entity_generator = fetch_entity_rows(
                    entity=entity,
                    start_iso=start_iso if use_time_filter else None,
                    end_iso=end_iso if use_time_filter else None,
                    page_size=page_size,
                    headers=headers,
                    api_base=api_base
                )

                for row in entity_generator:
                    # Store raw Citrix data directly for proper parser recognition
                    rows_batch.append(row)

                    # Write in batches to avoid memory issues
                    if len(rows_batch) >= 1000:
                        gcs_key = f"{prefix}/{entity}/year={target_hour.year:04d}/month={target_hour.month:02d}/day={target_hour.day:02d}/hour={target_hour.hour:02d}/part-{uuid.uuid4().hex}.ndjson"
                        write_ndjson_to_gcs(bucket, gcs_key, rows_batch)
                        total_records += len(rows_batch)
                        rows_batch = []

            except Exception as ex:
                print(f"Error processing entity {entity}: {str(ex)}")
                continue

            # Write remaining records
            if rows_batch:
                gcs_key = f"{prefix}/{entity}/year={target_hour.year:04d}/month={target_hour.month:02d}/day={target_hour.day:02d}/hour={target_hour.hour:02d}/part-{uuid.uuid4().hex}.ndjson"
                write_ndjson_to_gcs(bucket, gcs_key, rows_batch)
                total_records += len(rows_batch)

        # Update state file
        save_state(bucket, state_key, target_hour)

        print(f"Successfully processed {total_records} records for hour {start_iso}")
        print(f"Entities processed: {', '.join(entities)}")

    except Exception as e:
        print(f'Error processing Citrix Monitor logs: {str(e)}')
        raise

Second file: requirements.txt:

functions-framework==3.*
google-cloud-storage==2.*
urllib3>=2.0.0

Click Deploy to save and deploy the function.
Wait for deployment to complete (2-3 minutes).

Create Cloud Scheduler job

Cloud Scheduler publishes messages to the Pub/Sub topic at regular intervals, triggering the Cloud Run function.

In the GCP Console, go to Cloud Scheduler.
Click Create Job.

Provide the following configuration details:

Setting	Value
Name	`citrix-monitor-collector-hourly`
Region	Select same region as Cloud Run function
Frequency	`0 * * * *` (every hour, on the hour)
Timezone	Select timezone (UTC recommended)
Target type	Pub/Sub
Topic	Select the topic (`citrix-monitor-trigger`)
Message body	`{}` (empty JSON object)

Click Create.

Test the scheduler job

In the Cloud Scheduler console, find your job.
Click Force run to trigger manually.
Wait a few seconds and go to Cloud Run > Services > citrix-monitor-collector > Logs.
Verify the function executed successfully.
Check the GCS bucket to confirm logs were written.

Retrieve the Google SecOps service account

Google SecOps uses a unique service account to read data from your GCS bucket. You must grant this service account access to your bucket.

Get the service account email

Go to SIEM Settings > Feeds.
Click Add New Feed.
Click Configure a single feed.
In the Feed name field, enter a name for the feed (for example, Citrix Monitor Service logs).
Select Google Cloud Storage V2 as the Source type.
Select Citrix Monitor as the Log type.
Click Get Service Account. A unique service account email will be displayed, for example:
```
chronicle-12345678@chronicle-gcp-prod.iam.gserviceaccount.com
```
Copy this email address for use in the next step.

Note: Each Google SecOps instance has a unique service account. Don't use service accounts from other documentation or examples.

Grant IAM permissions to the Google SecOps service account

The Google SecOps service account needs Storage Object Viewer role on your GCS bucket.

Go to Cloud Storage > Buckets.
Click your bucket name.
Go to the Permissions tab.
Click Grant access.
Provide the following configuration details:
- Add principals: Paste the Google SecOps service account email.
- Assign roles: Select Storage Object Viewer.
Click Save.

Note: If you plan to use the deletion option "Delete transferred files" or "Delete transferred files and empty directories," grant Storage Object Admin role instead of Storage Object Viewer.

Configure a feed in Google SecOps to ingest Citrix Monitor Service logs

Go to SIEM Settings > Feeds.
Click Add New Feed.
Click Configure a single feed.
In the Feed name field, enter a name for the feed (for example, Citrix Monitor Service logs).
Select Google Cloud Storage V2 as the Source type.
Select Citrix Monitor as the Log type.
Click Next.
Specify values for the following input parameters:
- Storage bucket URL: Enter the GCS bucket URI with the prefix path:
```
gs://citrix-monitor-logs/citrix_monitor/
```
  - Replace:
    - citrix-monitor-logs: Your GCS bucket name.
    - citrix_monitor: Optional prefix/folder path where logs are stored (leave empty for root).
  Note: Always include the trailing slash (/) at the end of the URI.
- Source deletion option: Select the deletion option according to your preference:
  - Never: Never deletes any files after transfers (recommended for testing).
  - Delete transferred files: Deletes files after successful transfer.
  - Delete transferred files and empty directories: Deletes files and empty directories after successful transfer.
    
    Note: If you select a deletion option, the service account must have Storage Object Admin role instead of Storage Object Viewer. Update IAM permissions accordingly.
- Maximum File Age: Include files modified in the last number of days. Default is 180 days.
- Asset namespace: The asset namespace.
- Ingestion labels: The label to be applied to the events from this feed.
Click Next.
Review your new feed configuration in the Finalize screen, and then click Submit.

Need more help? Get answers from Community members and Google SecOps professionals.