"Fix" conflicts with 3rd party libraries using CocoaLumberjack

[rivera-ernesto]

As discussed in #162, there's no solution to sharing ddLogLevel between libraries and the client application:

• Apps/libraries may define ddLogLevel as a const, extern, int, a function returning an int, etc. Each one incompatible with the other.
• Even more, if apps/libraries used a compatible and shared ddLogLevel there would be no way to manage separately log levels from each one.

The solution is to define a LOG_LEVEL_DEF by default equal to ddLogLevel so apps can continue to work as usual.

3rd party libraries simple redefine LOG_LEVEL_DEF to something different:

// #undef LOG_LEVEL_DEF // Undefine first only if needed
#define LOG_LEVEL_DEF myLibLogLevel

3rd party frameworks need to be updated.

[bpoplauschi]

Looks good @rivera-ernesto . Thanks for doing this

[rivera-ernesto]

Now we need to ask library devs to update their CocoaLumberjack usage:

 * Step 1:
 * Import the header in your implementation file:
 * 
 * #import "DDLog.h"
 * 
 * Step 2:
 * Define your logging level in your implementation file:
 * 
 * // Log levels: off, error, warn, info, verbose
 * static const int ddLogLevel = LOG_LEVEL_VERBOSE;
 * 
 * Step 2 [3rd party frameworks]:
 *
 * Define your LOG_LEVEL_DEF to a different variable/function than ddLogLevel:
 *
 * // #undef LOG_LEVEL_DEF // Undefine first only if needed
 * #define LOG_LEVEL_DEF myLibLogLevel
 *
 * Define your logging level in your implementation file:
 *
 * // Log levels: off, error, warn, info, verbose
 * static const int myLibLogLevel = LOG_LEVEL_VERBOSE;
 *
 * Step 3:
 * Replace your NSLog statements with DDLog statements according to the severity of the message.
 * 
 * NSLog(@"Fatal error, no dohickey found!"); -> DDLogError(@"Fatal error, no dohickey found!");

We'll also need some proper documentation for this in the README and/or Wiki.

[rivera-ernesto]

Creating a 1.6.4 release so they can point this release in their specs' requirements.

[augustj]

Looks like a great solution. Thanks for working it out.

[ealeksandrov]

https://github.com/robbiehanson/CocoaLumberjack/wiki/XcodeTricks - this is still true, considering last changes?

I am recieving error, when building with CocoaLumberjack and MagicalRecord as pods:

Pods/Headers/MagicalRecord/MagicalRecord.h:27:20: Redefinition of 'ddLogLevel' with a different type: 'int' vs 'const int'

How can I supress this, from my side? Or this requires changes from MagicalRecord?

[rivera-ernesto]

https://github.com/robbiehanson/CocoaLumberjack/wiki/XcodeTricks - this is still true, considering last changes?

It is, but only for the host application. Frameworks could do the same with their levels:

#ifdef DEBUG
  static const int myLibLogLevel = LOG_LEVEL_WARN; // Probably not VERBOSE here!
#else
  static const int myLibLogLevel = LOG_LEVEL_ERROR;
#endif

[rivera-ernesto]

I am receiving error, when building with CocoaLumberjack and MagicalRecord as pods:
Pods/Headers/MagicalRecord/MagicalRecord.h:27:20: Redefinition of 'ddLogLevel' with a different type: 'int' vs 'const int'
How can I supress this, from my side? Or this requires changes from MagicalRecord?

For now you could redefine LOG_LEVEL_DEF for your app:

#define LOG_LEVEL_DEF myAppLogLevel

// Just before
#import <DDLog/DDLog.h>

Then you replace ddLogLevel by myAppLogLevel in your code.

[ealeksandrov]

@rivera-ernesto thanks for this hints!
But now, if we are defining in 3rd party, like:

#define LOG_LEVEL_DEF MRLogLevel
static const int MRLogLevel = LOG_LEVEL_WARN;

including this define along with whole library - will override pch setting for application log level.
What am I doing wrong?

The only solution that I see - to import DDLog.h with LOG_LEVEL_DEF redefine at top of every .m file in my project (but after all other imports).
Step 1 confirms this? No way to use one declaration in pch now?

And about proposed temporary solution:

[rivera-ernesto]

Yes, you have to define LOG_LEVEL_DEF before importing <DDLog/DDLog.h>. You can either:

• Do it inside every *.m file;
• Add it to your library's prefix file if you build the library yourself.
• Let CocoaPods add it to your library's prefix file:

  s.prefix_header_contents = <<-EOS
  #ifdef __OBJC__  
        #define LOG_LEVEL_DEF MRLogLevel
        static const int MRLogLevel = LOG_LEVEL_WARN;
        #import <DDLog/DDLog.h>
        //...
  #endif

• Create a Private.h header that you import in all your *.m files and also define there any values and shared code that your library needs. Personally I do this.

[rivera-ernesto]

I'm trying to make CocoaLumberjack optional for my libraries (sample). Use it if available, else fallback to NSLog.

// a) Use NBULog for logging when available
#ifdef COCOAPODS_POD_AVAILABLE_NBULog

#import "NBULog+NBUKit.h"

#define NBUKIT_LOG_LEVEL    [NBULog kitLogLevel]

// Customize NBULog macros
#undef  NBULogError
#define NBULogError(frmt, ...)  LOG_OBJC_MAYBE(LOG_ASYNC_ERROR,   NBUKIT_LOG_LEVEL, LOG_FLAG_ERROR,   NBUKIT_LOG_CONTEXT, frmt, ##__VA_ARGS__)
#undef  NBULogWarn
#define NBULogWarn(frmt, ...)   LOG_OBJC_MAYBE(LOG_ASYNC_WARN,    NBUKIT_LOG_LEVEL, LOG_FLAG_WARN,    NBUKIT_LOG_CONTEXT, frmt, ##__VA_ARGS__)
#undef  NBULogInfo
#define NBULogInfo(frmt, ...)   LOG_OBJC_MAYBE(LOG_ASYNC_INFO,    NBUKIT_LOG_LEVEL, LOG_FLAG_INFO,    NBUKIT_LOG_CONTEXT, frmt, ##__VA_ARGS__)
#undef  NBULogDebug
#define NBULogDebug(frmt, ...)  LOG_OBJC_MAYBE(LOG_ASYNC_DEBUG,   NBUKIT_LOG_LEVEL, LOG_FLAG_DEBUG,   NBUKIT_LOG_CONTEXT, frmt, ##__VA_ARGS__)
#undef  NBULogVerbose
#define NBULogVerbose(frmt, ...)LOG_OBJC_MAYBE(LOG_ASYNC_VERBOSE, NBUKIT_LOG_LEVEL, LOG_FLAG_VERBOSE, NBUKIT_LOG_CONTEXT, frmt, ##__VA_ARGS__)


// b) Else try CocoaLumberjack
#elif defined(COCOAPODS_POD_AVAILABLE_CocoaLumberjack)

#ifdef DEBUG
    #define NBUKitLogLevel LOG_LEVEL_VERBOSE
#else
    #define NBUKitLogLevel LOG_LEVEL_WARN
#endif

#define LOG_LEVEL_DEF   NBUKitLogLevel
#import <CocoaLumberjack/DDLog.h>

#define NBULogError(frmt, ...)      DDLogError(frmt, ##__VA_ARGS__)
#define NBULogWarn(frmt, ...)       DDLogWarn(frmt, ##__VA_ARGS__)
#define NBULogInfo(frmt, ...)       DDLogInfo(frmt, ##__VA_ARGS__)
#define NBULogDebug(frmt, ...)      DDLogDebug(frmt, ##__VA_ARGS__)
#define NBULogVerbose(frmt, ...)    DDLogVerbose(frmt, ##__VA_ARGS__)
#define NBULogTrace()               NBULogDebug(@"%@", THIS_METHOD)


// c) Else fallback to NSLog
#else

#ifdef DEBUG
    #define LOG_LEVEL 3
#else
    #define LOG_LEVEL 2
#endif

#define THIS_METHOD                 NSStringFromSelector(_cmd)
#define NBULogError(frmt, ...)      do{ if(LOG_LEVEL >= 1) NSLog((frmt), ##__VA_ARGS__); } while(0)
#define NBULogWarn(frmt, ...)       do{ if(LOG_LEVEL >= 2) NSLog((frmt), ##__VA_ARGS__); } while(0)
#define NBULogInfo(frmt, ...)       do{ if(LOG_LEVEL >= 3) NSLog((frmt), ##__VA_ARGS__); } while(0)
#define NBULogDebug(frmt, ...)      do{ if(LOG_LEVEL >= 4) NSLog((frmt), ##__VA_ARGS__); } while(0)
#define NBULogVerbose(frmt, ...)    do{ if(LOG_LEVEL >= 5) NSLog((frmt), ##__VA_ARGS__); } while(0)
#define NBULogTrace()               NBULogDebug(@"%@", THIS_METHOD)

#endif

This could be extended to other log frameworks allowing app developers to use the one they prefer.