JAMES-3221 #comment Improved logging around configuration files for d…

…evops

* When loading a configuration file, print it's absolute
* Usefull for debugging production miss-configurations
* Added documentation

docs/modules/development/pages/logging.adoc

@@ -0,0 +1,43 @@
+= Logging in Apache James
+
+NOTE: This information targets developers.
+
+Logging is very important when running a software.
+Most of the time people use logs for debugging and troubleshooting issues in production.
+In Apache James we leverage a logging facade for logging http://www.slf4j.org/[Slf4j] .
+Please see the documentation for exact details.
+
+In a typical application logs are stored for a specific period.
+This can be 1 day, 1 week, etc.
+
+Some other typical scenarios include:
+
+* Rotating logs periodically.
+* Shipping logs centrally.
+* Saving some logging messages to other files / end devices
+
+By leveraging a logging facade like Slf4j, the end user has the ability to use different logging back ends and achieve the above requirements.
+
+Logging is something we do to help the people running our code.
+We also help ourselves when they encounter bugs, and they need to share information with us for a fix.
+As developers, we should be mindful of the logging statements.
+We should also be mindful about the performance implications of logging and not abuse it.
+
+== Loggers used in code
+
+You can define a logger using a string or a class.
+For common loggers it's ok to use a string name.
+
+[source,java]
+--
+    private static final Logger LOGGER = LoggerFactory.getLogger("org.apache.james.CONFIGURATION");
+    private static final Logger LOGGER = LoggerFactory.getLogger(JamesServerMain.class);
+--
+
+Loggers can be hierarchical.
+This helps when we build a logger from a class name, and we use package structure to drive the logger hierarchy.
+
+The most useful loggers should to be documented below.
+Please maintain this list of loggers.
+
+org.apache.james.CONFIGURATION:: It is used to log events related to configuration loading and updating.

server/container/core/src/main/java/org/apache/james/server/core/JamesServerResourceLoader.java

@@ -20,6 +20,8 @@
 
 import org.apache.james.filesystem.api.JamesDirectoriesProvider;
 
+import com.google.common.base.MoreObjects;
+
 public class JamesServerResourceLoader implements JamesDirectoriesProvider {
 
     private final String rootDirectory;
@@ -58,4 +60,12 @@ public String getRootDirectory() {
         return rootDirectory;
     }
 
+    @Override
+    public String toString() {
+        return MoreObjects.toStringHelper(this)
+            .add("rootDirectory", rootDirectory)
+            .add("varDirectory", getVarDirectory())
+            .add("confDirectory", getConfDirectory())
+            .toString();
+    }
 }

server/container/core/src/main/java/org/apache/james/server/core/configuration/Configuration.java

@@ -134,6 +134,14 @@ public ConfigurationPath configurationPath() {
         public JamesDirectoriesProvider directories() {
             return directories;
         }
+
+        @Override
+        public String toString() {
+            return MoreObjects.toStringHelper(this)
+                .add("configurationPath", configurationPath)
+                .add("directories", directories)
+                .toString();
+        }
     }
 
     static Basic.Builder builder() {

server/container/guice/cassandra-guice/src/main/java/org/apache/james/CassandraJamesServerMain.java

@@ -171,6 +171,7 @@ public static void main(String[] args) throws Exception {
             .useWorkingDirectoryEnvProperty()
             .build();
 
+        LOGGER.info("Loading configuration {}", configuration.toString());
         GuiceJamesServer server = createServer(configuration)
             .combineWith(new JMXServerModule());
 

server/container/guice/cassandra-ldap-guice/src/main/java/org/apache/james/CassandraLdapJamesServerMain.java

@@ -37,6 +37,7 @@ public static void main(String[] args) throws Exception {
             .useWorkingDirectoryEnvProperty()
             .build();
 
+        LOGGER.info("Loading configuration {}", configuration.toString());
         GuiceJamesServer server = createServer(configuration)
             .combineWith(new JMXServerModule());
 

server/container/guice/cassandra-rabbitmq-guice/src/main/java/org/apache/james/CassandraRabbitMQJamesServerMain.java

@@ -44,6 +44,7 @@ public static void main(String[] args) throws Exception {
             .useWorkingDirectoryEnvProperty()
             .build();
 
+        LOGGER.info("Loading configuration {}", configuration.toString());
         GuiceJamesServer server = createServer(configuration)
             .combineWith(new JMXServerModule());
 

server/container/guice/cassandra-rabbitmq-ldap-guice/src/main/java/org/apache/james/CassandraRabbitMQLdapJamesServerMain.java

@@ -38,6 +38,7 @@ public static void main(String[] args) throws Exception {
             .useWorkingDirectoryEnvProperty()
             .build();
 
+        LOGGER.info("Loading configuration {}", configuration.toString());
         GuiceJamesServer server = createServer(configuration)
             .combineWith(new JMXServerModule());
 

server/container/guice/configuration/src/main/java/org/apache/james/utils/PropertiesProvider.java

@@ -35,13 +35,16 @@
 import org.apache.commons.configuration2.ex.ConfigurationException;
 import org.apache.james.filesystem.api.FileSystem;
 import org.apache.james.server.core.configuration.Configuration.ConfigurationPath;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import com.google.common.base.Joiner;
 import com.google.common.base.Preconditions;
 import com.google.common.base.Strings;
 
 public class PropertiesProvider {
 
+    private static final Logger LOGGER = LoggerFactory.getLogger("org.apache.james.CONFIGURATION");
     private static final char COMMA = ',';
     private static final String COMMA_STRING = ",";
 
@@ -85,7 +88,9 @@ private Configuration getConfiguration(File propertiesFile) throws Configuration
 
     private Optional<File> getConfigurationFile(String fileName) {
         try {
-            return Optional.of(fileSystem.getFile(configurationPrefix.asString() + fileName + ".properties"))
+            File file = fileSystem.getFile(configurationPrefix.asString() + fileName + ".properties");
+            LOGGER.info("Load configuration file {}", file.getAbsolutePath());
+            return Optional.of(file)
                 .filter(File::exists);
         } catch (FileNotFoundException e) {
             return Optional.empty();

server/container/guice/guice-common/src/main/java/org/apache/james/JamesServerMain.java

@@ -19,7 +19,13 @@
 
 package org.apache.james;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 public interface JamesServerMain {
+
+    Logger LOGGER = LoggerFactory.getLogger("org.apache.james.CONFIGURATION");
+
     static void main(GuiceJamesServer server) throws Exception {
         server.start();
 

server/container/guice/jpa-guice/src/main/java/org/apache/james/JPAJamesServerMain.java

@@ -101,6 +101,7 @@ public static void main(String[] args) throws Exception {
             .useWorkingDirectoryEnvProperty()
             .build();
 
+        LOGGER.info("Loading configuration {}", configuration.toString());
         GuiceJamesServer server = createServer(configuration)
             .combineWith(new JMXServerModule());
 

server/container/guice/jpa-smtp-common/src/main/java/org/apache/james/JPAJamesServerMain.java

@@ -64,6 +64,7 @@ public static void main(String[] args) throws Exception {
             .useWorkingDirectoryEnvProperty()
             .build();
 
+        LOGGER.info("Loading configuration {}", configuration.toString());
         GuiceJamesServer server = createServer(configuration);
 
         JamesServerMain.main(server);

server/container/guice/memory-guice/src/main/java/org/apache/james/MemoryJamesServerMain.java

@@ -138,7 +138,7 @@ public static void main(String[] args) throws Exception {
             .useWorkingDirectoryEnvProperty()
             .build();
 
-
+        LOGGER.info("Loading configuration {}", configuration.toString());
         GuiceJamesServer server = createServer(configuration)
             .combineWith(new FakeSearchMailboxModule(), new JMXServerModule());