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Message Levels

Message levels in SciMLLogging determine the severity and importance of log messages. Understanding these levels is essential for configuring appropriate verbosity in your applications.

Overview

SciMLLogging provides a hierarchy of message levels that correspond to different types of information:

SciMLLogging.AbstractMessageLevel — Type
AbstractMessageLevel

Abstract base type for all verbosity log levels in SciMLLogging.

Log levels determine the severity/importance of messages. Concrete subtypes include:

  • Silent: No output
  • DebugLevel: Debug messages
  • InfoLevel: Informational messages
  • WarnLevel: Warning messages
  • ErrorLevel: Error messages
  • CustomLevel(n): Custom log level with integer value n
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Each of the AbstractMessageLevels correspond to a Julia Logging LogLevel type with an associated integer, besides Silent. See the Julia Logging documentation for more details.

Standard Message Levels

Silent Level

SciMLLogging.Silent — Type
Silent <: AbstractMessageLevel

Log level that produces no output. When a message category is set to Silent(), no messages will be emitted for that category.

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The Silent level is special - it completely suppresses output for a message. As such, it does not have an associated LogLevel.

Debug Level

SciMLLogging.DebugLevel — Type
DebugLevel <: AbstractMessageLevel

Debug log level. Messages at this level provide detailed debugging information, typically more verbose than informational messages. Useful for development and troubleshooting.

Corresponds to Logging.Debug == Logging.LogLevel(-1000) when using the Logging backend.

By default, these messages are not logged at all, and the JULIA_DEBUG environment variable needs to be set. For details see the Julia Logging documentation.

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DebugLevel() is for messages with a very low priority. By default, these messages are not logged at all, and the JULIA_DEBUG environment variable needs to be set. For details see the Julia Logging documentation.

Information Level

SciMLLogging.InfoLevel — Type
InfoLevel <: AbstractMessageLevel

Informational log level. Messages at this level provide general information about the progress or state of the computation.

Corresponds to Logging.Info == Logging.LogLevel(0) when using the Logging backend.

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Use InfoLevel() for general status updates, progress information, and routine diagnostic messages that users might want to see during normal operation.

Warning Level

SciMLLogging.WarnLevel — Type
WarnLevel <: AbstractMessageLevel

Warning log level. Messages at this level indicate potential issues or situations that may require attention but don't prevent execution.

Corresponds to Logging.Warn == Logging.LogLevel(1000) when using the Logging backend.

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WarnLevel() should be used for potentially problematic situations that don't prevent execution but may require user attention.

Error Level

SciMLLogging.ErrorLevel — Type
ErrorLevel <: AbstractMessageLevel

Error log level. Messages at this level indicate serious problems or failures in the computation.

Corresponds to Logging.Warn == Logging.LogLevel(2000) when using the Logging backend.

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ErrorLevel() is reserved for serious problems and failures that indicate something has gone wrong in the computation.

Custom Message Levels

SciMLLogging.CustomLevel — Type
CustomLevel(n::Int) <: AbstractMessageLevel

Custom log level with integer value n. This allows creating custom severity levels beyond the standard Info/Warn/Error hierarchy.

Corresponds to Logging.LogLevel(n), where n is any integer, when using the Logging backend.

Higher integer values typically indicate higher priority/severity.

Example

debug_level = CustomLevel(-1000)  # Very low priority debug messages
critical_level = CustomLevel(1000)  # Very high priority critical messages
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Custom levels provide flexibility for specialized use cases where the standard Info/Warn/Error hierarchy isn't sufficient.

Usage Examples

using SciMLLogging

# Standard levels
debug_level = DebugLevel()
info_level = InfoLevel()
warn_level = WarnLevel()
error_level = ErrorLevel()
silent_level = Silent()

# Custom levels for specialized needs
trace_level = CustomLevel(-500)     # Low priority debugging
critical_level = CustomLevel(2000)  # Higher than standard error level

Level Hierarchy

The message levels have a natural hierarchy that affects logging behavior:

  • Silent(): No output (always suppressed)
  • DebugLevel(): Lowest priority message
  • InfoLevel(): Low priority for general information
  • WarnLevel(): Medium priority
  • ErrorLevel(): Highest standard priority
  • CustomLevel(n): Priority determined by integer value n

Higher priority messages are more likely to be displayed by logging systems, while lower priority messages may be filtered out depending on the logger configuration.