Logger

The Logger operation records incoming data to an internal, slot-scoped memory log. It serves as a monitoring and debugging utility — data is not passed further down the execution path. Logged entries are viewable through the system UI, not via an output port.

Inputs

Port	Type	Required	Description
> (Gate)	Any	No	When connected, a false or Nil value stops the path. See Gate Inputs.
Data	Any	Yes	Data values to log. Up to 10 connectable inputs.

Outputs

This operation has no outputs. The execution path always stops after the Logger executes.

Properties

Name	Type	Default	Description
Name	TextLine	"Logger"	Display name for this logger instance. Appears as a column in the shared slot log table. Use unique names to distinguish entries from different loggers.
On Error	Combo	Stop this branch	Per-op On Error verb. Logger is a sink, so the Editor offers it the two verbs a sink can honour: Stop this branch / Continue with the last value. See the Error Handling guide.

State on Reload

The Logger does not preserve log entries across system restarts. Logs are kept in slot memory and cleared on system reload. Individual operation reloads within a task do not clear the log.

Slot-level configuration

Two slot-level settings control log behaviour:

• logMemoryLines (default 100) — maximum number of log entries kept in memory. Oldest entries are removed when the limit is exceeded (FIFO).
• logLineMaxBytes (default 100) — maximum byte length per logged value after string conversion. Values exceeding this are truncated at a UTF-8 boundary. Set to 0 to disable truncation.

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How It Works

1. Gate check — If a Gate Input is connected, evaluate it. A false or Nil value stops the execution path; no entry is created. If the gate is not connected, logging always occurs.

2. Log entry — A new entry is created containing a timestamp, the Name, and the string-converted values of all connected data inputs.

3. Capacity management — If the log reaches logMemoryLines, the oldest entry is removed.

4. Path end — The Logger has no outputs, so the execution path naturally ends at this Node.

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Data Conversion

• Strings are logged as-is.
• Binary data is logged as UTF-8 text if valid; otherwise as its MessagePack text representation.
• All other MessagePack types use their text representation.
• Each value may be truncated to logLineMaxBytes bytes (UTF-8 safe).

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Examples

Data format

All inputs and outputs use MessagePack internally. The examples below show values in JSON notation for readability.

Basic String

Gate: (not connected)   Input 1: "User logged in: Alice"

A log entry is created with timestamp, logger name, and the value "User logged in: Alice". The execution path stops.

Multiple Inputs

Gate: true   Input 1: "Sensor A"   Input 2: 25.5   Input 3: "Celsius"

A single log entry is created with all three values.

Gate Blocked

Gate: false   Input 1: "Attempted Action"   Input 2: {"error": "permission denied"}

The gate is closed — no entry is created and the execution path stops at this Node.

Mixed Types

Gate: 1 (non-Boolean, non-Nil — passes)   Input 1: "Task Completed"   Input 2: true   Input 3: Nil

All three values are logged, including Nil.

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Use Cases

• Debugging complex workflows by inspecting intermediate data at specific points.
• Monitoring sensor readings or event streams during development.
• Auditing user actions or system events in real time.

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Error Handling

Logger can hit one error: the underlying addLog call throws (for example, the slot’s log buffer is in a transient bad state).

It triggers the On Error verb you picked. See the Error Handling guide for the common On Error model; Logger’s options are:

Verb	What it does
Stop this branch (default)	This Node and its dependents stop. Nodes that do not depend on this one still run.
Continue with the last value	Path continues.

Logger is a sink: it has no Output, so there is nothing for Continue with the fallback to write. Its schema states the two verbs above, and the Editor offers only those.

Gate closure is not an error — a closed Gate stops the Path and consults no verb.

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Limitations

• Log capacity is limited by logMemoryLines (default 100). Older entries are automatically removed.
• Log data lives in memory and is lost on system restart.
• Logged data is only viewable through the system UI, not via an output port.

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Configuration

Two host settings bound Logger. Both are read at start-up from the host’s configuration file; see the Core configuration reference.

Key	Type	Default	Effect
logLineMaxBytes	Integer	100	Where a logged value is truncated, in bytes. Truncation respects UTF-8 boundaries, so a multi-byte character is never split. 0 disables truncation.
logMemoryLines	Integer	100	How many lines the in-memory log ring holds before the oldest is dropped. 0 is treated as the default.

Both keys are unprefixed: they are read under those names, not under core..