Logger Structure Reference


                    
                    
                    label

An identifier of the creator of this Logger.

Declaration

Swift

public let label: String

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                    log(level:_:metadata:source:file:function:line:)

Log a message passing the log level as a parameter.

If the logLevel passed to this method is more severe than the Logger‘s logLevel, it will be logged, otherwise nothing will happen.

Declaration

Swift

@inlinable
public func log(level: Logger.Level,
                _ message: @autoclosure () -> Logger.Message,
                metadata: @autoclosure () -> Logger.Metadata? = nil,
                source: @autoclosure () -> String? = nil,
                file: String = #fileID, function: String = #function, line: UInt = #line)

Parameters

`level`	The log level to log `message` at. For the available log levels, see `Logger.Level`.
`message`	The message to be logged. `message` can be used with any string interpolation literal.
`metadata`	One-off metadata to attach to this log message.
`source`	The source this log messages originates from. Defaults to the module emitting the log message (on Swift 5.3 or newer and the folder name containing the log emitting file on Swift 5.2 or older).
`file`	The file this log message originates from (there’s usually no need to pass it explicitly as it defaults to `#fileID` (on Swift 5.3 or newer and `#file` on Swift 5.2 or older).
`function`	The function this log message originates from (there’s usually no need to pass it explicitly as it defaults to `#function`).
`line`	The line this log message originates from (there’s usually no need to pass it explicitly as it defaults to `#line`).

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                    log(level:_:metadata:source:file:function:line:)


                    
                    
                    log(level:_:metadata:file:function:line:)

Undocumented

Declaration

Swift

@inlinable
public func log(level: Logger.Level,
                _ message: @autoclosure () -> Logger.Message,
                metadata: @autoclosure () -> Logger.Metadata? = nil,
                file: String = #fileID, function: String = #function, line: UInt = #line)

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                    log(level:_:metadata:file:function:line:)


                    
                    
                    subscript(metadataKey:)

Add, change, or remove a logging metadata item.

Note

Logging metadata behaves as a value that means a change to the logging metadata will only affect the very Logger it was changed on.

Declaration

Swift

@inlinable
public subscript(metadataKey metadataKey: String) -> Logger.Metadata.Value? { get set }

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                    logLevel

Get or set the log level configured for this Logger.

Note

Loggers treat logLevel as a value. This means that a change in logLevel will only affect this very Logger. It is acceptable for logging backends to have some form of global log level override that affects multiple or even all loggers. This means a change in logLevel to one Logger might in certain cases have no effect.

Declaration

Swift

@inlinable
public var logLevel: Logger.Level { get set }

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                    trace(_:metadata:source:file:function:line:)

Undocumented

Declaration

Swift

@inlinable
public func trace(_ message: @autoclosure () -> Logger.Message,
                  metadata: @autoclosure () -> Logger.Metadata? = nil,
                  source: @autoclosure () -> String? = nil,
                  file: String = #fileID, function: String = #function, line: UInt = #line)

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                    trace(_:metadata:source:file:function:line:)


                    
                    
                    trace(_:metadata:file:function:line:)

Undocumented

Declaration

Swift

@inlinable
public func trace(_ message: @autoclosure () -> Logger.Message,
                  metadata: @autoclosure () -> Logger.Metadata? = nil,
                  file: String = #fileID, function: String = #function, line: UInt = #line)

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                    trace(_:metadata:file:function:line:)


                    
                    
                    debug(_:metadata:source:file:function:line:)

Undocumented

Declaration

Swift

@inlinable
public func debug(_ message: @autoclosure () -> Logger.Message,
                  metadata: @autoclosure () -> Logger.Metadata? = nil,
                  source: @autoclosure () -> String? = nil,
                  file: String = #fileID, function: String = #function, line: UInt = #line)

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                    debug(_:metadata:source:file:function:line:)


                    
                    
                    debug(_:metadata:file:function:line:)

Undocumented

Declaration

Swift

@inlinable
public func debug(_ message: @autoclosure () -> Logger.Message,
                  metadata: @autoclosure () -> Logger.Metadata? = nil,
                  file: String = #fileID, function: String = #function, line: UInt = #line)

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                    debug(_:metadata:file:function:line:)


                    
                    
                    info(_:metadata:source:file:function:line:)

Undocumented

Declaration

Swift

@inlinable
public func info(_ message: @autoclosure () -> Logger.Message,
                 metadata: @autoclosure () -> Logger.Metadata? = nil,
                 source: @autoclosure () -> String? = nil,
                 file: String = #fileID, function: String = #function, line: UInt = #line)

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                    info(_:metadata:source:file:function:line:)


                    
                    
                    info(_:metadata:file:function:line:)

Undocumented

Declaration

Swift

@inlinable
public func info(_ message: @autoclosure () -> Logger.Message,
                 metadata: @autoclosure () -> Logger.Metadata? = nil,
                 file: String = #fileID, function: String = #function, line: UInt = #line)

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                    info(_:metadata:file:function:line:)


                    
                    
                    notice(_:metadata:source:file:function:line:)

Undocumented

Declaration

Swift

@inlinable
public func notice(_ message: @autoclosure () -> Logger.Message,
                   metadata: @autoclosure () -> Logger.Metadata? = nil,
                   source: @autoclosure () -> String? = nil,
                   file: String = #fileID, function: String = #function, line: UInt = #line)

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                    notice(_:metadata:source:file:function:line:)


                    
                    
                    notice(_:metadata:file:function:line:)

Undocumented

Declaration

Swift

@inlinable
public func notice(_ message: @autoclosure () -> Logger.Message,
                   metadata: @autoclosure () -> Logger.Metadata? = nil,
                   file: String = #fileID, function: String = #function, line: UInt = #line)

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                    notice(_:metadata:file:function:line:)


                    
                    
                    warning(_:metadata:source:file:function:line:)

Undocumented

Declaration

Swift

@inlinable
public func warning(_ message: @autoclosure () -> Logger.Message,
                    metadata: @autoclosure () -> Logger.Metadata? = nil,
                    source: @autoclosure () -> String? = nil,
                    file: String = #fileID, function: String = #function, line: UInt = #line)

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                    warning(_:metadata:source:file:function:line:)


                    
                    
                    warning(_:metadata:file:function:line:)

Undocumented

Declaration

Swift

@inlinable
public func warning(_ message: @autoclosure () -> Logger.Message,
                    metadata: @autoclosure () -> Logger.Metadata? = nil,
                    file: String = #fileID, function: String = #function, line: UInt = #line)

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                    warning(_:metadata:file:function:line:)


                    
                    
                    error(_:metadata:source:file:function:line:)

Undocumented

Declaration

Swift

@inlinable
public func error(_ message: @autoclosure () -> Logger.Message,
                  metadata: @autoclosure () -> Logger.Metadata? = nil,
                  source: @autoclosure () -> String? = nil,
                  file: String = #fileID, function: String = #function, line: UInt = #line)

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                    error(_:metadata:source:file:function:line:)


                    
                    
                    error(_:metadata:file:function:line:)

Undocumented

Declaration

Swift

@inlinable
public func error(_ message: @autoclosure () -> Logger.Message,
                  metadata: @autoclosure () -> Logger.Metadata? = nil,
                  file: String = #fileID, function: String = #function, line: UInt = #line)

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                    error(_:metadata:file:function:line:)


                    
                    
                    critical(_:metadata:source:file:function:line:)

Undocumented

Declaration

Swift

@inlinable
public func critical(_ message: @autoclosure () -> Logger.Message,
                     metadata: @autoclosure () -> Logger.Metadata? = nil,
                     source: @autoclosure () -> String? = nil,
                     file: String = #fileID, function: String = #function, line: UInt = #line)

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                    critical(_:metadata:source:file:function:line:)


                    
                    
                    critical(_:metadata:file:function:line:)

Undocumented

Declaration

Swift

@inlinable
public func critical(_ message: @autoclosure () -> Logger.Message,
                     metadata: @autoclosure () -> Logger.Metadata? = nil,
                     file: String = #fileID, function: String = #function, line: UInt = #line)

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                    critical(_:metadata:file:function:line:)


                    
                    
                    Metadata

Metadata is a typealias for [String: Logger.MetadataValue] the type of the metadata storage.

Declaration

Swift

public typealias Metadata = [String : MetadataValue]

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                    MetadataValue

A logging metadata value. Logger.MetadataValue is string, array, and dictionary literal convertible.

MetadataValue provides convenient conformances to ExpressibleByStringInterpolation, ExpressibleByStringLiteral, ExpressibleByArrayLiteral, and ExpressibleByDictionaryLiteral which means that when constructing MetadataValues you should default to using Swift’s usual literals.

Examples:

prefer logger.info("user logged in", metadata: ["user-id": "\(user.id)"]) over ..., metadata: ["user-id": .string(user.id.description)])
prefer logger.info("user selected colors", metadata: ["colors": ["\(user.topColor)", "\(user.secondColor)"]]) over ..., metadata: ["colors": .array([.string("\(user.topColor)"), .string("\(user.secondColor)")])
prefer logger.info("nested info", metadata: ["nested": ["fave-numbers": ["\(1)", "\(2)", "\(3)"], "foo": "bar"]]) over ..., metadata: ["nested": .dictionary(["fave-numbers": ...])])

Declaration

Swift

public enum MetadataValue

extension Logger.MetadataValue: Equatable

extension Logger.MetadataValue: ExpressibleByStringLiteral

extension Logger.MetadataValue: CustomStringConvertible

extension Logger.MetadataValue: ExpressibleByStringInterpolation

extension Logger.MetadataValue: ExpressibleByDictionaryLiteral

extension Logger.MetadataValue: ExpressibleByArrayLiteral

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                    Level

The log level.

Log levels are ordered by their severity, with .trace being the least severe and .critical being the most severe.

Declaration

Swift

public enum Level : String, Codable, CaseIterable

extension Logger.Level: Comparable

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                    init(label:)

Construct a Logger given a label identifying the creator of the Logger.

The label should identify the creator of the Logger. This can be an application, a sub-system, or even a datatype.

Declaration

Swift

public init(label: String)

Parameters


                                label

An identifier for the creator of a Logger.

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                    init(label:factory:)

Construct a Logger given a label identifying the creator of the Logger or a non-standard LogHandler.

The label should identify the creator of the Logger. This can be an application, a sub-system, or even a datatype.

This initializer provides an escape hatch in case the global default logging backend implementation (set up using LoggingSystem.bootstrap is not appropriate for this particular logger.

Declaration

Swift

public init(label: String, factory: (String) -> LogHandler)

Parameters

`label`	An identifier for the creator of a `Logger`.
`factory`	A closure creating non-standard `LogHandler`s.

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                    Message

Logger.Message represents a log message’s text. It is usually created using string literals.

Example creating a Logger.Message:

let world: String = "world"
let myLogMessage: Logger.Message = "Hello \(world)"

Most commonly, Logger.Messages appear simply as the parameter to a logging method such as:

logger.info("Hello \(world)")

Declaration

Swift

public struct Message : ExpressibleByStringLiteral, Equatable, CustomStringConvertible, ExpressibleByStringInterpolation

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