How to integrate programmatic configuration in log4j?

Question

I am using Log4j version 2.0.1 version and due to organisation policies, I cannot use any higher version for the time-being.

group:'org.apache.logging.log4j',name:'log4j-core',version:'2.0.1'
group:'org.apache.logging.log4j',name:'log4j-api',version:'2.0.1'

My Requirements for logging

1. If customDebug=true as environment variable, then enable debug logging
2. There should be 2 logging files generated -- one primary logging (info/debug based on above logs) and error logging.
3. Have a size based rolling strategy
4. The directory of the log files is dynamic.
5. The format should carry the time in certain styling along with thread id.

I tried implementing programmatic configuration of log4j in the following manner --

CustomConfigFactory.java >>

@Plugin(name = "CustomConfigFactory", category = "JsonConfigurationFactory")
@Order(10)
public class CustomConfigFactory extends JsonConfigurationFactory {

    @Override
    public String[] getSupportedTypes() {
        return new String[] {".json"};
    }

    @Override
    public Configuration getConfiguration(ConfigurationSource cs) {
        try{
            String file = Thread.currentThread().getContextClassLoader().getResource("customRollingConfiguration.json").getFile()
            cs = new ConfigurationSource(new FileInputStream(new File(file ));
        } catch (Exception e){
            System.err.println("ERROR : Exception encountered while initiating configuration source: "+e);
        }
        return new CustomJsonConfiguration(cs);
    }

}

CustomJsonConfiguration.java >>

public class CustomJsonConfiguration extends JsonConfiguration {

    public CustomJsonConfiguration(final ConfigurationSource configSource) {
        super(configSource);
    }

    @Override
    protected void doConfigure(){
        try {
            ConfigurationSource source = this.getConfigurationSource();
            Configuration config = CustomConfigFactory.getInstance().getConfiguration(source);

            final Layout layout = PatternLayout.createLayout("%d{yyyy-MM-dd HH:mm:ss.SSS} %-5p [%5T] %c{1}:%L - %m%n",
                config,null,Charset.defaultCharset(),true,false,"","");

            SizeBasedTriggeringPolicy policy = SizeBasedTriggeringPolicy.createPolicy("10 MB");
            DefaultRolloverStrategy strategy = DefaultRolloverStrategy.createStrategy("50", "5", "min", "9", config);

            String logDir = System.getenv("log_dir");
            String primaryLogFile = logDir+"/my_main_log";
            String primaryLogFilePattern = primaryLogFile+"-backup-%d{MM-dd-yy-HH-mm-ss}-%i.log.gz";

            String errorLogFile = logDir+"/my_err_log";
            String errorLogFilePattern = errorLogFile+"-backup-%d{MM-dd-yy-HH-mm-ss}-%i.log.gz";

            RollingFileAppender appender1 = RollingFileAppender.createAppender(primaryLogFile,
                primaryLogFilePattern,"true", "debugFile","true", "false","false",
                policy, strategy, layout, null, null, null, null, config);
            appender1.start();;

            RollingFileAppender appender2 = RollingFileAppender.createAppender(errorLogFile,
                errorLogFilePattern,"true","errorFile","true","false","false",
                policy, strategy, layout, null,null,null,null, config);
            appender2.start();;

            config.addAppender(appender1);
            config.addAppender(appender2);

            LoggerConfig primaryLoggerConfig = null;
            if(Boolean.valueOf(System.getenv("customDebug")){
                 primaryLoggerConfig = new LoggerConfig("aa.bb.cc.dd",Level.DEBUG,false);
            } else {
                primaryLoggerConfig = new LoggerConfig("aa.bb.cc.dd",Level.INFO,false);
            }
            LoggerConfig errorLoggerConfig = new LoggerConfig("aa.bb.cc.dd",Level.ERROR,false);

            primaryLoggerConfig.addAppender(appender1,null,null);
            errorLoggerConfig.addAppender(appender2,null,null);
            config.addLogger("aa.bb.cc.dd",primaryLoggerConfig);
            config.addLogger("aa.bb.cc.dd",errorLoggerConfig);

            LoggerContext context = new LoggerContext("default_context");
            context.start(config);
        } catch (Exception e){
            System.err.println("");
        }
    }

where the aa.bb.cc.dd refers to the package name of the MyClass below.

MyClass.java where this logger will be used >>

package aa.bb.cc.dd;

public MyClass {
    static final Logger myCustomLog = LogManager.getLogger(MyClass.class);

    void doSomething(){
        myCustomLog.info("Doing something");
    }
}

Sample Test Method as part of a testng class for testing the above class >>>

@Test
public void testDoingSomething(){
    MyClass m1 = new MyClass();
    m1.doSomething();
}

But the above doesn't seem to work and none of the log files are getting generated i.e. logging is not working. I have primarily referred to this for the implementation - -https://logging.apache.org/log4j/2.x/manual/customconfig.html#Hybrid

I'd appreciate if anybody could help me out with this implementation. All suggestions welcomed !!!

Thanks in advance.

EDIT >>> Following is the configuration json after incorporating @VikasSachdeva's comments. The error file is still empty even thought an ERROR condition is being logged in my_main.log

{
  "configuration": {
     "name": "RollingKitConfig",
    "Appenders": {
  "appender": [
    {
      "type": "RollingFile",
      "name": "debugFile",
      "fileName": "${env:log_dir}/my_main_log",
      "filePattern": "${env:log_dir  }/my_main_backup-%d{MM-dd-yy-HH-mm-ss}-%i.log.gz",
      "PatternLayout": {
        "pattern": "%d{yyyy-MM-dd HH:mm:ss,nnn} [%-5p] [%5t] [%c{3}:%L] - %m%n"
      },
      "Policies": {
        "SizeBasedTriggeringPolicy": {
          "size": "10 MB"
        }
      },
      "DefaultRolloverStrategy": {
        "max": "10"
      },
      "ThresholdFilter": {
        "level": "${env:customDebug:-info}"
      }
    },
    {
      "type": "RollingFile",
      "name": "errorFile",
      "fileName": "${env:log_dir}/errors.log",
      "filePattern": "${env:log_dir}/errors_backup-%d{MM-dd-yy-HH-mm-ss}-%i.log.gz",
      "PatternLayout": {
        "pattern": "%d{yyyy-MM-dd HH:mm:ss,nnn} [%-5p] [%5t] [%c{1}:%L] - %m%n"
      },
      "Policies": {
        "SizeBasedTriggeringPolicy": {
          "size": "10 MB"
        }
      },
      "DefaultRolloverStrategy": {
        "max": "10"
      },
      "ThresholdFilter": {
        "level": "ERROR",
        "onMatch": "ACCEPT",
        "onMisMatch": "DENY"
      }
    }
  ]
},
"Loggers": {
  "logger": [
    {
      "name": "KitLogger",
      "level": "info",
      "additivity": "false",
      "AppenderRef": [
        {
          "ref": "debugFile"
        },
        {
          "ref": "errorFile"
        }
      ]
    }
  ],
  "root": {
    "level": "debug",
    "appender-ref": {
      "ref": "debugFile"
    }
  }
}
  }
}

Answer 1

If you just want to pick log file location using environment variables, you can do so using configuration file alone as describe in log4j2 documentation

Considering your environment variable is log_dir=D:/logs/. Then you can change your configuration like below -

{
    "configuration": {
        "name": "RollingConfig",
        "ThresholdFilter": { "level": "info" },
        "properties": {
            "property": {
                "name": "basePath",
                "value": "${env:log_dir}"
             }
        },
        "appenders": {
            "RollingFile": {
                "name": "debugFile",
                "fileName": "${basePath}my_main.log",
                "filePattern": "${basePath}my_main_%d{yyyyMMdd}.log.gz",
                "PatternLayout": { "pattern": "%d{yyyy-MM-dd HH:mm:ss} %-5p [%5T] %c{1}:%L - %m%n" },
                "Policies": {
                    "SizeBasedTriggeringPolicy": { "size": "10 MB" }
                },
               "DefaultRolloverStrategy": { "max": "10"  }
            },
            "RollingFile": {
                "name": "errorFile",
                "fileName": "${basePath}my_err.log",,
                "filePattern": "${basePath}my_err_%d{yyyyMMdd}.log.gz",
                "thresholdFilter": {
                    "level": "ERROR",
                    "onMatch": "ACCEPT",
                    "onMisMatch": "DENY"
                },
                "PatternLayout": { "pattern": "%d{yyyy-MM-dd HH:mm:ss} %-5p [%5T] %c{1}:%L - %m%n" },
                "Policies": {
                     "SizeBasedTriggeringPolicy": {  "size": "10 MB" }
                },
                "DefaultRolloverStrategy": {"max": "10"}
            }
        },
        "loggers": {
            "logger": {
                 "name": "mainLogger",
                 "level": "info",
                 "additivity": "false",
                 "appender-ref": [ 
                                 {"ref": "debugFile"}, 
                                 { "ref":"errorFile"}
                                 ]
            },
            "root": {
                "level": "info",
                 "appender-ref": [ 
                                 {"ref": "debugFile" }, 
                                 { "ref":"errorFile" }
                                 ]
             }
          }
       }
}