Background: Workflow Execution Model

Agents and Schedulers

AutomationEdge relies on agents—lightweight runtime components—to execute workflows deployed from the server. The scheduler triggers these executions based on time, event, or API calls. Failures often occur due to discrepancies in plugin configurations, stale caches, or JVM-related constraints on agent machines.

Plugin Architecture

AutomationEdge workflows use plugins for integrations—database access, PowerShell, JavaScript, web services, etc. Poorly configured plugins or invalid parameters can cause the agent to hang, especially when exception handling is not enforced within the workflow.

Symptoms of the Issue

• Workflows remain in Running state indefinitely
• Error logs show SocketTimeoutException or Agent Communication Failed
• Scheduled jobs start but never complete
• Database or REST steps time out inconsistently

Root Causes

1. Agent JVM Heap Exhaustion

Large datasets or recursive workflows can consume more heap than allocated. When this happens, the agent becomes unresponsive and the workflow appears hung in the UI.

java.lang.OutOfMemoryError: Java heap space

2. Plugin Parameter Mismatch

REST or SQL plugins often fail silently when optional parameters are malformed or missing. Without proper validation, execution hangs while waiting for a response that will never arrive.

3. Orphaned Threads from Asynchronous Tasks

Custom scripts using threads or external processes may spawn subprocesses that do not terminate properly, causing zombie executions.

4. Agent-Server Heartbeat Delay

In distributed environments, network latency or firewall rules may block the agent's heartbeat, resulting in missed health checks or dropped job updates.

Diagnostic Process

1. Check Agent Logs

Location: /AutomationEdge/agent/logs/agent.log

Look for: OutOfMemoryError, Connection refused, Plugin step stuck, or NullPointerException

2. Monitor JVM Memory Usage

Use jconsole or jvisualvm to attach to the agent process and observe heap space, GC activity, and thread count.

3. Enable Workflow Execution Tracing

In the workflow designer, enable execution log at each step to trace where the workflow stalls.

4. Validate Plugin Versions

Ensure consistency across all agents. Mismatched plugin versions can cause undefined behaviors during execution.

Step-by-Step Remediation

1. Increase Agent Heap Size

# In agent startup script
JAVA_OPTS="-Xms1024m -Xmx4096m"

Restart the agent after configuration changes.

2. Add Timeouts to Plugins

For REST, JDBC, and Email plugins, explicitly set connection and execution timeouts to prevent indefinite waits.

3. Implement Try-Catch Around Scripts

Always handle exceptions inside JavaScript, PowerShell, and Shell script steps to avoid abrupt thread termination.

try {
  // risky operation
} catch(e) {
  logger.info("Script error: " + e);
  jobResult = "FAILED";
}

4. Use Process Cleanup Scripts

Schedule a cleanup job that periodically kills stale OS processes left behind by failed bot executions.

ps aux | grep java | grep -v AutomationEdge | awk '{print $2}' | xargs kill -9

5. Upgrade Agents and Plugins

Always align agent versions with server and plugin compatibility matrix provided in the AutomationEdge release notes.

Best Practices for Stability

• Version Control: Maintain centralized plugin repositories and avoid unapproved custom plugin versions.
• Retry Logic: Implement retry steps for API and DB operations to handle transient failures.
• Monitoring: Use external monitoring (e.g., Nagios, Prometheus) to track agent memory, CPU, and process health.
• Workflow Modularity: Break down large workflows into smaller, reusable units to isolate failure domains.
• Alerting: Configure alerts for workflows stuck in Running state beyond expected duration.

Conclusion

AutomationEdge provides powerful orchestration capabilities, but reliability depends heavily on proper agent configuration, plugin usage, and workflow design discipline. Workflow execution deadlocks and agent-related failures can be mitigated with JVM tuning, better error handling, and operational monitoring. Proactive governance ensures automation remains scalable and resilient across enterprise landscapes.

FAQs

1. How can I tell if an agent is truly stuck?

If the workflow remains in Running state and the agent log has no updates for several minutes, it's likely unresponsive. Use thread dumps to confirm.

2. What causes memory leaks in workflows?

Repeated data loading, unclosed DB connections, and large object retention in scripts can lead to JVM heap exhaustion.

3. Is plugin mismatch between agents and server critical?

Yes. Even minor version mismatches can introduce breaking changes or undefined behavior during plugin execution.

4. Can I use external schedulers with AutomationEdge?

Yes. You can trigger workflows via REST API from external tools like Control-M, Jenkins, or Airflow.

5. How to ensure plugin parameter validity?

Use workflow parameter validation logic at the start or encapsulate plugin steps in test routines during staging.