log

The log package provides structured logging with severity levels, optional timestamps, and optional file output. Output goes to stderr; log lines below the configured minimum level are suppressed.

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Log Levels

Levels in ascending severity order: DEBUG → INFO → WARN → ERROR → FATAL

Only messages at or above the configured level are emitted. The default level is INFO.

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Package Functions

set_level(level)

Sets the minimum log level. Messages below this level are silently dropped.

Parameters

Type	Name	Description
string	level	One of "DEBUG", "INFO", "WARN", "ERROR", "FATAL"

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set_file(path)

Appends log output to a file in addition to stderr. Pass null to disable file output.

Parameters

Type	Name	Description
string\|null	path	File path, or null to disable

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timestamps(enabled)

Enables or disables timestamps in log lines. Enabled by default.

Parameters

Type	Name	Description
boolean	enabled	true to include timestamps

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debug(msg)

Logs a DEBUG message.

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info(msg)

Logs an INFO message.

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warn(msg)

Logs a WARN message.

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error(msg)

Logs an ERROR message.

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fatal(msg)

Logs a FATAL message and calls exit(1).

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All logging functions accept:

Type	Name	Description
any	msg	The message to log

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Output Format

[LEVEL] [timestamp] message

Example:

[INFO] [2026-03-22 18:00:00Z] Server started
[WARN] [2026-03-22 18:01:05Z] Disk usage above 80%
[ERROR] [2026-03-22 18:02:11Z] Connection refused

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Examples

import "log"

log::info("Application starting")
log::debug("This won't appear — default level is INFO")

log::set_level("DEBUG")
log::debug("Now debug messages are visible")

log::warn("Low memory")
log::error("Failed to connect to database")

File output

import "log"

log::set_file("/var/log/myapp.log")
log::set_level("WARN")

log::info("This is suppressed")
log::warn("This goes to stderr AND the file")
log::error("So does this")

Disable timestamps

import "log"

log::timestamps(false)
log::info("Clean output without timestamps")
# [INFO] Clean output without timestamps

Fatal error

import "log"

cfg = load_config()
if cfg == null
  log::fatal("Could not load configuration — aborting")
  # Process exits here with code 1
end