[log.fatal]

log.fatal is a slot in the log namespace, in Hyperlambda, the language of Magic Cloud. Writes a fatal-level log entry; reserve for unrecoverable failures that warrant immediate attention.

• Value (log-message,text), required: Log message to write
• Returns: Id of the log entry created, or null if the configured log level filtered it out

Arguments

Required arguments come first, then the optional ones in the order they are declared.

Argument	Type	Required	Description
any node name	string	no	Metadata entry stored with the log item when the slot has an input value; otherwise evaluated content fragment. Can be repeated.
[exception]	string	no	Exception text attached to error and fatal log entries.

Guide

How to use log.fatal

JSON declaration

This is the complete declaration of log.fatal, as the running system describes it. It is also published as slot.json.

JSON declaration

{
  "name": "log.fatal",
  "description": "Writes a fatal-level log entry; reserve for unrecoverable failures that warrant immediate attention",
  "signature": {
    "input": {
      "kind": "log-message,text",
      "description": "Log message to write",
      "required": true,
      "mode": "ValueOrExpression"
    },
    "children": {
      "*": {
        "type": "string",
        "kind": "log-metadata",
        "description": "Metadata entry stored with the log item when the slot has an input value; otherwise evaluated content fragment",
        "required": false,
        "mode": "ValueOrExpression",
        "cardinality": "ZeroOrMore",
        "role": "DynamicMap",
        "evaluation": "EvalSelf",
        "projection": "Value"
      },
      "exception": {
        "type": "string",
        "kind": "exception-text",
        "description": "Exception text attached to error and fatal log entries",
        "required": false,
        "mode": "ValueOrExpression",
        "cardinality": "ZeroOrOne",
        "role": "Option",
        "projection": "Value"
      }
    },
    "output": {
      "mode": "Value",
      "kind": "log-entry-id",
      "description": "Id of the log entry created, or null if the configured log level filtered it out"
    }
  }
}

---

← log.error

all log.* slots

log.get →