DDDispatchQueueLogFormatter

Objective-C

@interface DDDispatchQueueLogFormatter : NSObject <DDLogFormatter>

Swift

class DDDispatchQueueLogFormatter : NSObject, DDLogFormatter

This class provides a log formatter that prints the dispatch_queue label instead of the mach_thread_id.

A log formatter can be added to any logger to format and/or filter its output. You can learn more about log formatters here: Documentation/CustomFormatters.md

A typical NSLog (or DDTTYLogger) prints detailed info as [<process_id>:<thread_id>]. For example:

2011-10-17 20:21:45.435 AppName[19928:5207] Your log message here

Where: - 19928 = process id - 5207 = thread id (mach_thread_id printed in hex)

When using grand central dispatch (GCD), this information is less useful. This is because a single serial dispatch queue may be run on any thread from an internally managed thread pool. For example:

2011-10-17 20:32:31.111 AppName[19954:4d07] Message from my_serial_dispatch_queue 2011-10-17 20:32:31.112 AppName[19954:5207] Message from my_serial_dispatch_queue 2011-10-17 20:32:31.113 AppName[19954:2c55] Message from my_serial_dispatch_queue

This formatter allows you to replace the standard [box:info] with the dispatch_queue name. For example:

2011-10-17 20:32:31.111 AppName[img-scaling] Message from my_serial_dispatch_queue 2011-10-17 20:32:31.112 AppName[img-scaling] Message from my_serial_dispatch_queue 2011-10-17 20:32:31.113 AppName[img-scaling] Message from my_serial_dispatch_queue

If the dispatch_queue doesn’t have a set name, then it falls back to the thread name. If the current thread doesn’t have a set name, then it falls back to the mach_thread_id in hex (like normal).

Note: If manually creating your own background threads (via NSThread/alloc/init or NSThread/detachNeThread), you can use [[NSThread currentThread] setName:(NSString *)].

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  • Standard init method. Configure using properties as desired.

    Declaration

    Objective-C

    - (nonnull instancetype)init;

    Swift

    init()
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  • Deprecated

    DDDispatchQueueLogFormatter is always shareable

    Initializer with ability to set the queue mode

    Declaration

    Objective-C

    - (nonnull instancetype)initWithMode:(DDDispatchQueueLogFormatterMode)mode;

    Swift

    convenience init(mode: DDDispatchQueueLogFormatterMode)

    Parameters

    mode

    choose between DDDispatchQueueLogFormatterModeShareble and DDDispatchQueueLogFormatterModeNonShareble, depending if the formatter is shared between several loggers or not
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  • The minQueueLength restricts the minimum size of the [detail box]. If the minQueueLength is set to 0, there is no restriction.

    For example, say a dispatch_queue has a label of “diskIO”:

    If the minQueueLength is 0: [diskIO] If the minQueueLength is 4: [diskIO] If the minQueueLength is 5: [diskIO] If the minQueueLength is 6: [diskIO] If the minQueueLength is 7: [diskIO ] If the minQueueLength is 8: [diskIO ]

    The default minQueueLength is 0 (no minimum, so [detail box] won’t be padded).

    If you want every [detail box] to have the exact same width, set both minQueueLength and maxQueueLength to the same value.

    Declaration

    Objective-C

    @property NSUInteger minQueueLength;

    Swift

    var minQueueLength: UInt { get set }
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  • The maxQueueLength restricts the number of characters that will be inside the [detail box]. If the maxQueueLength is 0, there is no restriction.

    For example, say a dispatch_queue has a label of “diskIO”:

    If the maxQueueLength is 0: [diskIO] If the maxQueueLength is 4: [disk] If the maxQueueLength is 5: [diskI] If the maxQueueLength is 6: [diskIO] If the maxQueueLength is 7: [diskIO] If the maxQueueLength is 8: [diskIO]

    The default maxQueueLength is 0 (no maximum, so [detail box] won’t be truncated).

    If you want every [detail box] to have the exact same width, set both minQueueLength and maxQueueLength to the same value.

    Declaration

    Objective-C

    @property NSUInteger maxQueueLength;

    Swift

    var maxQueueLength: UInt { get set }
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  • Sometimes queue labels have long names like “com.apple.main-queue”, but you’d prefer something shorter like simply “main”.

    This method allows you to set such preferred replacements. The above example is set by default.

    To remove/undo a previous replacement, invoke this method with nil for the ‘shortLabel’ parameter.

    Declaration

    Objective-C

    - (nullable NSString *)replacementStringForQueueLabel:
    (nonnull NSString *)longLabel;

    Swift

    func replacementString(forQueueLabel longLabel: String) -> String?
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  • See the replacementStringForQueueLabel: description

    Declaration

    Objective-C

    - (void)setReplacementString:(nullable NSString *)shortLabel
               forQueueLabel:(nonnull NSString *)longLabel;

    Swift

    func setReplacementString(_ shortLabel: String?, forQueueLabel longLabel: String)
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OverridableMethods