Try Node

The try node provides structured error handling, similar to try/catch/finally in programming languages. Use it to gracefully handle errors and ensure cleanup code runs.

Configuration

{
  "id": "safe_api_call",
  "type": "try",
  "config": {
    "try": ["fetch_data", "process_data"],
    "catch": ["handle_error"],
    "finally": ["cleanup"]
  }
}

Config Fields

Field	Type	Required	Description
`try`	string[]	Yes	Node IDs to execute (at least one required)
`catch`	string[]	No	Node IDs to execute if an error occurs
`finally`	string[]	No	Node IDs that always execute

Execution Flow

      try block
          |
    +-----+-----+
    |           |
 success      error
    |           |
    |        catch block
    |           |
    +-----+-----+
          |
    finally block
          |
       continue

Execute all nodes in try
If error occurs, execute catch nodes
Always execute finally nodes
Continue with flow

Output

On Success

{
  "success": true,
  "result": { ... },
  "error": null,
  "failed_node": null
}

On Error

{
  "success": false,
  "result": null,
  "error": "connection timeout",
  "failed_node": "fetch_data"
}

Field	Type	Description
`success`	boolean	Whether try block completed without error
`result`	any	Output from last successful node
`error`	string	Error message if failed
`failed_node`	string	ID of node that failed

Error Context

In the catch block, error information is available:

Expression	Description
`{{error.message}}`	The error message
`{{error.node}}`	ID of the node that failed
`{{error.type}}`	Type of error

Examples

Basic Error Handling

{
  "id": "fetch_with_fallback",
  "type": "try",
  "config": {
    "try": ["fetch_from_primary_api"],
    "catch": ["fetch_from_backup_api"]
  }
}

With Cleanup

{
  "id": "transaction",
  "type": "try",
  "config": {
    "try": ["start_transaction", "process_payment", "commit"],
    "catch": ["rollback"],
    "finally": ["release_lock"]
  }
}

Logging Errors

[
  {
    "id": "safe_operation",
    "type": "try",
    "config": {
      "try": ["risky_operation"],
      "catch": ["log_error", "set_fallback"],
      "finally": ["track_metrics"]
    }
  },
  {
    "id": "log_error",
    "type": "set",
    "config": {
      "key": "error_log",
      "value": {
        "message": "{{error.message}}",
        "node": "{{error.node}}",
        "timestamp": "{{now}}"
      }
    }
  },
  {
    "id": "set_fallback",
    "type": "set",
    "config": {
      "key": "result",
      "value": {
        "data": [],
        "source": "fallback",
        "error": "{{error.message}}"
      }
    }
  }
]

API Call with Fallback Response

[
  {
    "id": "try_fetch",
    "type": "try",
    "config": {
      "try": ["fetch_user_data", "transform_data"],
      "catch": ["set_default_data"]
    }
  },
  {
    "id": "fetch_user_data",
    "type": "http",
    "config": {
      "url": "https://api.example.com/users/{{user_id}}",
      "timeout": 5000
    }
  },
  {
    "id": "set_default_data",
    "type": "set",
    "config": {
      "key": "user_data",
      "value": {
        "id": "{{user_id}}",
        "name": "Unknown",
        "loaded_from": "fallback"
      }
    }
  }
]

Conditional Error Response

[
  {
    "id": "try_operation",
    "type": "try",
    "config": {
      "try": ["validate", "process"],
      "catch": ["set_error"]
    }
  },
  {
    "id": "set_error",
    "type": "set",
    "config": {
      "key": "operation_error",
      "value": {
        "failed": true,
        "message": "{{error.message}}",
        "recoverable": true
      }
    }
  },
  {
    "id": "check_error",
    "type": "condition",
    "config": {
      "conditions": [
        {
          "if": "{{operation_error.failed}} == true",
          "then": ["error_response"]
        }
      ],
      "else": ["success_response"]
    }
  }
]

Nested Try Blocks

Try nodes can be nested for granular error handling:

[
  {
    "id": "outer_try",
    "type": "try",
    "config": {
      "try": ["inner_try", "final_step"],
      "catch": ["catastrophic_error"]
    }
  },
  {
    "id": "inner_try",
    "type": "try",
    "config": {
      "try": ["risky_step"],
      "catch": ["recover_from_risky"]
    }
  }
]

Use Cases

API Resilience

Wrap external API calls to handle failures gracefully:

{
  "try": ["call_external_api"],
  "catch": ["use_cached_data"],
  "finally": ["log_attempt"]
}

Transaction Safety

Ensure rollback happens if processing fails:

{
  "try": ["begin_tx", "update_db", "commit_tx"],
  "catch": ["rollback_tx", "log_failure"]
}

Resource Cleanup

Always release resources regardless of success/failure:

{
  "try": ["acquire_lock", "do_work"],
  "finally": ["release_lock"]
}

Error Propagation

If catch handles the error, the flow continues normally
If catch itself fails, the error propagates up
finally always runs, even if catch fails

Abort Node - Explicitly fail the flow
Condition Node - Check error status
HTTP Node - Has built-in on_error option

Getting Started

Triggers

Nodes

Reference

Configuration

Config Fields

Execution Flow

Output

On Success

On Error

Error Context

Examples

Basic Error Handling

With Cleanup

Logging Errors

API Call with Fallback Response

Conditional Error Response

Nested Try Blocks

Use Cases

API Resilience

Transaction Safety

Resource Cleanup

Error Propagation

​Configuration

​Config Fields

​Execution Flow

​Output

​On Success

​On Error

​Error Context

​Examples

​Basic Error Handling

​With Cleanup

​Logging Errors

​API Call with Fallback Response

​Conditional Error Response

​Nested Try Blocks

​Use Cases

​API Resilience

​Transaction Safety

​Resource Cleanup

​Error Propagation

​Related

Configuration

Config Fields

Execution Flow

Output

On Success

On Error

Error Context

Examples

Basic Error Handling

With Cleanup

Logging Errors

API Call with Fallback Response

Conditional Error Response

Nested Try Blocks

Use Cases

API Resilience

Transaction Safety

Resource Cleanup

Error Propagation

Related