How to remove all debug logging calls before building the release version of an Android app

Question

According to Google  I must  deactivate any calls to Log methods in the source code  before publishing my Android app to Google Play  Extract from section 3 of the publication checklist      Make sure you deactivate logging and disable the debugging option before you build your application for release  You can deactivate logging by removing calls to Log methods in your source files    My open-source project is large and it is a pain to do it manually every time I release  Additionally  removing a Log line is potentially tricky  for instance   if condition    Log d LOG TAG   Something    data load    data show      If I comment the Log line  then the condition applies to the next line  and chances are load   is not called  Are such situations rare enough that I can decide it should not exist   So  is there a better source code-level way to do that  Or maybe some clever ProGuard syntax to efficiently but safely remove all Log lines

User · Answer

I suggest having a static boolean somewhere indicating whether or not to log:

class MyDebug {
  static final boolean LOG = true;
}

Then wherever you want to log in your code, just do this:

if (MyDebug.LOG) {
  if (condition) Log.i(...);
}

Now when you set MyDebug.LOG to false, the compiler will strip out all code inside such checks (since it is a static final, it knows at compile time that code is not used.)

For larger projects, you may want to start having booleans in individual files to be able to easily enable or disable logging there as needed. For example, these are the various logging constants we have in the window manager:

static final String TAG = "WindowManager";
static final boolean DEBUG = false;
static final boolean DEBUG_FOCUS = false;
static final boolean DEBUG_ANIM = false;
static final boolean DEBUG_LAYOUT = false;
static final boolean DEBUG_RESIZE = false;
static final boolean DEBUG_LAYERS = false;
static final boolean DEBUG_INPUT = false;
static final boolean DEBUG_INPUT_METHOD = false;
static final boolean DEBUG_VISIBILITY = false;
static final boolean DEBUG_WINDOW_MOVEMENT = false;
static final boolean DEBUG_ORIENTATION = false;
static final boolean DEBUG_APP_TRANSITIONS = false;
static final boolean DEBUG_STARTING_WINDOW = false;
static final boolean DEBUG_REORDER = false;
static final boolean DEBUG_WALLPAPER = false;
static final boolean SHOW_TRANSACTIONS = false;
static final boolean HIDE_STACK_CRAWLS = true;
static final boolean MEASURE_LATENCY = false;

With corresponding code like:

    if (DEBUG_FOCUS || DEBUG_WINDOW_MOVEMENT) Log.v(
        TAG, "Adding window " + window + " at "
        + (i+1) + " of " + mWindows.size() + " (after " + pos + ")");

User · Answer

the simplest way   use DebugLog   All logs are disabled by DebugLog when the app is released   https   github com MustafaFerhan DebugLog

User · Answer

my Way   1  enable Column Selection Mode  alt shift insert   2  select on one Log d TAG   text    the part  Log    3  then do shift   ctrl   alt   j  4  click left arrow  5  do shift end  6  hit delete   this removes all LOG calls at once in a java file

User · Answer

As zserge s comment suggested      Timber is very nice  but if you already have an existing project - you may try github com zserge log   It s a drop-in replacement for android util Log and has most of the the features that Timber has and even more     his log library provides simple enable disable log printing switch as below   In addition  it only requires to change import lines  and nothing needs to change for Log d       statement   if   BuildConfig DEBUG      Log usePrinter Log ANDROID  false      from now on Log d etc do nothing and is likely to be optimized with JIT

User · Answer

I have improved on the solution above by providing support for different log levels and by changing the log levels automatically depending on if the code is being run on a live device or on the emulator   public class Log    final static int WARN   1  final static int INFO   2  final static int DEBUG   3  final static int VERB   4   static int LOG LEVEL   static       if   google sdk  equals Build PRODUCT      sdk  equals Build PRODUCT             LOG LEVEL   VERB        else           LOG LEVEL   INFO                   Error     public static void e String tag  String string            android util Log e tag  string             Warn     public static void w String tag  String string            android util Log w tag  string             Info     public static void i String tag  String string        if LOG LEVEL  gt   INFO                android util Log i tag  string                   Debug     public static void d String tag  String string        if LOG LEVEL  gt   DEBUG                android util Log d tag  string                   Verbose     public static void v String tag  String string        if LOG LEVEL  gt   VERB                android util Log v tag  string

User · Answer

Why not just do   if BuildConfig DEBUG    Log d  tag   msg        No additional libraries needed  no proguard rules which tend to screw up the project and java compiler will just leave out bytecode for for this call when you make release build

User · Answer

This is what i used to do on my android projects    In Android Studio we can do similar operation by  Ctrl Shift F to find from whole project  Command Shift F in MacOs  and Ctrl Shift R to Replace   Command Shift R in MacOs

User · Answer

I have a very simple solution  I use IntelliJ for development  so the details vary but the idea should apply across all IDE s   I pick to root of my source tree  right-click and select to do  replace   I then choose to replace all  Log   with    Log    This removes all log statements  To put them back later I repeat the same replace but this time as replace all    Log   with  Log     Works just great for me  Just remember to set the replace as case sensitive to avoid accidents such as  Dialog    For added assurance you can also do the first step with   Log   as the string to search   Brilliant

User · Answer

Easy with kotlin  just declare a few top level functions  val isDebug  Boolean     get     BuildConfig DEBUG  fun logE tag  String  message  String        if  isDebug  Log e tag  message     fun logD tag  String  message  String        if  isDebug  Log d tag  message

User · Answer

If you can run a global replace  once   and after that preserve some coding convention  you can follow the pattern often used in Android framework   Instead of writing  Log d TAG  string1   string2   arg3 toString       have it as  if  BuildConfig DEBUG  Log d TAG  string1   String format    2f   arg2    arg3 toString       Now proguard can remove the StringBuilder and all strings and methods it uses on the way  from optimized release DEX  Use proguard-android-optimize txt and you don t need to worry about android util Log in your proguard-rules pro   android           buildTypes       release         minifyEnabled true       proguardFiles getDefaultProguardFile  proguard-android-optimize txt     proguard-rules pro                With Android Studio gradle plugin  BuildConfig DEBUG is quite reliable  so you don t need extra constants to control the stripping

User · Answer

Logs can be removed using bash in linux and sed   find   -name     java    xargs sed -ri   a  s Log   ivdwe           ta   Log   ivdwe    b  N  ba    Works for multiline logs  In this solution you can be sure  that logs are not present in production code

User · Answer

You can try use this simple conventional method   Ctrl Shift R  replace   Log e    With     Log e

User · Answer

All good answers  but when I was finished with my development I didn  t want to either use if statements around all the Log calls  nor did I want to use external tools   So the solution I m using is to replace the android util Log class with my own Log class   public class Log       static final boolean LOG   BuildConfig DEBUG       public static void i String tag  String string            if  LOG  android util Log i tag  string             public static void e String tag  String string            if  LOG  android util Log e tag  string             public static void d String tag  String string            if  LOG  android util Log d tag  string             public static void v String tag  String string            if  LOG  android util Log v tag  string             public static void w String tag  String string            if  LOG  android util Log w tag  string             The only thing I had to do in all the source files was to replace the import of android util Log  with my own class

User · Answer

I like to use Log d TAG  some string  often a String format       TAG is always the class name  Transform Log d TAG  --  Logd  in the text of your class   private void Logd String str       if  MainClass debug  Log d className  str       In this way when you are ready to make a release version  set MainClass debug to false

User · Answer

I know this is an old question  but why didn t you replace all your log calls with something like Boolean logCallWasHere true    ---rest of your log here  This why you will know when you want to put them back  and they won t affect your if statement call

User · Answer

ProGuard will do it for you on your release build and now the good news from android com    http   developer android com tools help proguard html  The ProGuard tool shrinks  optimizes  and obfuscates your code by removing unused code and renaming classes  fields  and methods with semantically obscure names  The result is a smaller sized  apk file that is more difficult to reverse engineer  Because ProGuard makes your application harder to reverse engineer  it is important that you use it when your application utilizes features that are sensitive to security like when you are Licensing Your Applications   ProGuard is integrated into the Android build system  so you do not have to invoke it manually  ProGuard runs only when you build your application in release mode  so you do not have to deal with obfuscated code when you build your application in debug mode  Having ProGuard run is completely optional  but highly recommended   This document describes how to enable and configure ProGuard as well as use the retrace tool to decode obfuscated stack traces

User · Answer

This is how I solve it in my Kotlin Project before going to production  buildTypes           release               minifyEnabled true             proguardFiles getDefaultProguardFile  proguard-android-optimize txt     proguard-rules pro                   -assumenosideeffects class android util Log       public static boolean isLoggable java lang String  int       public static int d           public static int w           public static int v           public static int i           public static int e

User · Answer

I would consider using roboguice s logging facility instead of the built-in android util Log  Their facility automatically disables debug and verbose logs for release builds  Plus  you get some nifty features for free  e g  customizable logging behavior  additional data for every log and more   Using proguard could be quite a hassle and I wouldn t go through the trouble of configuring and making it work with your application unless you have a good reason for that  disabling logs isn t a good one

User · Answer

I would like to add some precisions about using Proguard with Android Studio and gradle  since I had lots of problems to remove log lines from the final binary   In order to make assumenosideeffects in Proguard works  there is a prerequisite    In your gradle file  you have to specify the usage of the proguard-android-optimize txt as default file   buildTypes       release           minifyEnabled true         proguardFiles getDefaultProguardFile  proguard-android-optimize txt     proguard-rules pro              With the file below  it does not work            proguardFiles getDefaultProguardFile  proguard-android txt     proguard-rules pro            Actually  in the default proguard-android txt file  optimization is disabled with the two flags   -dontoptimize -dontpreverify   The proguard-android-optimize txt file does not add those lines  so now assumenosideeffects can work   Then  personnally  I use SLF4J  all the more when I develop some libraries that are distributed to others  The advantage is that by default there is no output  And if the integrator wants some log outputs  he can uses Logback for Android and activate the logs  so logs can be  redirected to a file or to LogCat   If I really need to strip the logs from the final library  I then add to my Proguard file  after having enabled the proguard-android-optimize txt file of course    -assumenosideeffects class   implements org slf4j Logger       public     trace           public     debug           public     info           public     warn           public     error

User · Answer

I have used a LogUtils class like in the Google IO example application  I modified this to use an application specific DEBUG constant instead of BuildConfig DEBUG because BuildConfig DEBUG is unreliable  Then in my Classes I have the following   import static my app util LogUtils makeLogTag  import static my app util LogUtils LOGV   public class MyActivity extends FragmentActivity     private static final String TAG   makeLogTag MyActivity class      protected void onCreate Bundle savedInstanceState        super onCreate savedInstanceState        LOGV TAG   my message

User · Answer

Here is my solution if you don t want to mess with additional libraries or edit your code manually  I created this Jupyter notebook to go over all java files and comment out all the Log messages  Not perfect but it got the job done for me

User · Answer

If you want to use a programmatic approach instead of using ProGuard  then by creating your own class with two instances  one for debug and one for release  you can choose what to log in either circumstances  So  if you don t want to log anything when in release  simply implement a Logger that does nothing  like the example below  import android util Log  sealed class Logger defaultTag  String    null        protected val defaultTag  String   defaultTag     quot  APP-DEBUG  quot       abstract fun log string  String  tag  String   defaultTag       object LoggerDebug   Logger             override fun log string  String  tag  String                Log d tag  string                       object LoggerRelease   Logger             override fun log string  String  tag  String                companion object           private val isDebugConfig   BuildConfig DEBUG          val instance  Logger by lazy               if isDebugConfig              LoggerDebug             else                 LoggerRelease                     Then to use your logger class  class MainActivity   AppCompatActivity      private val logger   Logger instance  override fun onCreate savedInstanceState  Bundle         super onCreate savedInstanceState      setContentView R layout activity main      logger log  quot Activity launched    quot               myView setOnClickListener                        logger log  quot My View clicked  quot    quot View-click quot               UPDATE    If we want to avoid string concatenations for better performances  we can add an inline function with a lambda that will be called only in debug config     Add this function to the Logger class  inline fun commit block  Logger    - gt  Unit        if this is LoggerDebug          block invoke this     And then   logger commit        log  quot Logging without  myVar waste of resources quot    quot My fancy concat quot       Since we are using an inline function  there are no extra object allocation and no extra virtual method calls

User · Answer

Add following to your proguard-rules txt file  -assumenosideeffects class android util Log     public static     d         public static     w         public static     v         public static     i

User · Answer

I find a far easier solution is to forget all the if checks all over the place and just use ProGuard to strip out any Log d   or Log v   method calls when we call our Ant release target   That way  we always have the debug info being output for regular builds and don t have to make any code changes for release builds   ProGuard can also do multiple passes over the bytecode to remove other undesired statements  empty blocks and can automatically inline short methods where appropriate   For example  here s a very basic ProGuard config for Android   -dontskipnonpubliclibraryclasses -dontobfuscate -forceprocessing -optimizationpasses 5  -keep class   extends android app Activity -assumenosideeffects class android util Log       public static     d           public static     v           So you would save that to a file  then call ProGuard from Ant  passing in your just-compiled JAR and the Android platform JAR you re using   See also the examples in the ProGuard manual     Update  4 5 years later   Nowadays I used Timber for Android logging   Not only is it a bit nicer than the default Log implementation     the log tag is set automatically  and it s easy to log formatted strings and exceptions     but you can also specify different logging behaviours at runtime   In this example  logging statements will only be written to logcat in debug builds of my app   Timber is set up in my Application onCreate   method   if  BuildConfig DEBUG      Timber plant new Timber DebugTree         Then anywhere else in my code I can log easily   Timber d  Downloading URL   s   url   try              catch  IOException ioe      Timber e ioe   Bad things happened         See the Timber sample app for a more advanced example  where all log statements are sent to logcat during development and  in production  no debug statements are logged  but errors are silently reported to Crashlytics

User · Answer

I highly suggest using Timber from Jake Wharton  https   github com JakeWharton timber  it solves your issue with enabling disabling plus adds tag class automagically  just   public class MyApp extends Application      public void onCreate         super onCreate          Timber     if  BuildConfig DEBUG          Timber plant new DebugTree                     logs will only be used in your debug ver  and then use   Timber d  lol      or   Timber i  lol says  s   lol      to print   Your class   msg  without specyfing the tag

User · Answer

Per android util Log provides a way to enable disable log   public static native boolean isLoggable String tag  int level     Default the method isLoggable      returns false  only after you setprop in device likes this   adb shell setprop log tag MyAppTag DEBUG   It means any log above DEBUG level can be printed out  Reference android doc      Checks to see whether or not a log for the specified tag is loggable at the specified level  The default level of any tag is set   to INFO  This means that any level above and including INFO will be   logged  Before you make any calls to a logging method you should check   to see if your tag should be logged  You can change the default level   by setting a system property   setprop log tag      Where level is either VERBOSE  DEBUG  INFO  WARN  ERROR  ASSERT  or   SUPPRESS  SUPPRESS will turn off all logging for your tag  You can   also create a local prop file that with the following in it     log tag    and place that in  data local prop    So we could use custom log util   public final class Dlog        public static void v String tag  String msg                if  Log isLoggable tag  Log VERBOSE               Log v tag  msg              public static void d String tag  String msg                if  Log isLoggable tag  Log DEBUG               Log d tag  msg              public static void i String tag  String msg                if  Log isLoggable tag  Log INFO               Log i tag  msg              public static void w String tag  String msg                if  Log isLoggable tag  Log WARN               Log w tag  msg              public static void e String tag  String msg                if  Log isLoggable tag  Log ERROR               Log e tag  msg

User · Answer

I m posting this solution which applies specifically for Android Studio users  I also recently discovered Timber and have imported it successfully into my app by doing the following   Put the latest version of the library into your build gradle   compile  com jakewharton timber timber 4 1 1    Then in Android Studios  go to Edit -  Find -  Replace in Path     Type in Log e TAG  or however you have defined your Log messages into the  Text to find  textbox  Then you just replace it with Timber e     Click Find and then replace all    Android Studios will now go through all your files in your project and replace all the Logs with Timbers   The only problem I had with this method is that gradle does come up witha million error messages afterwards because it cannot find  Timber  in the imports for each of your java files  Just click on the errors and Android Studios will automatically import  Timber  into your java  Once you have done it for all your errors files  gradle will compile again   You also need to put this piece of code in your onCreate method of your Application class       if  BuildConfig DEBUG            Timber plant new Timber DebugTree             This will result in the app logging only when you are in development mode not in production  You can also have BuildConfig RELEASE for logging in release mode

User · Answer

Christopher s Proguard solution is the best  but if for any reason you don t like Proguard  here is a very low-tech solution   Comment logs   find   -name     java    xargs grep -l  Log      xargs sed -i  s Log         Log   g    Uncomment logs   find   -name     java    xargs grep -l  Log      xargs sed -i  s       Log   Log   g    A constraint is that your logging instructions must not span over multiple lines    Execute these lines in a UNIX shell at the root of your project  If using Windows  get a UNIX layer or use equivalent Windows commands

[android] How to remove all debug logging calls before building the release version of an Android app?

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