feature #10: first implementation of logger

build.gradle

@@ -18,7 +18,10 @@ dependencies {
     implementation "org.jetbrains.kotlin:kotlin-reflect:1.3.31"
     implementation "com.fasterxml.jackson.module:jackson-module-kotlin:2.9.9"
     implementation "com.github.jasync-sql:jasync-postgresql:0.9.53"
+    implementation "org.slf4j:slf4j-api:1.7.26"
 
+    testImplementation "ch.qos.logback:logback-classic:1.2.3"
+    testImplementation "ch.qos.logback:logback-core:1.2.3"
     testImplementation "io.mockk:mockk:1.9"
     testImplementation "org.junit.jupiter:junit-jupiter:5.4.2"
     testImplementation 'org.amshove.kluent:kluent:1.47'

src/main/kotlin/fr/postgresjson/connexion/Connection.kt

@@ -9,6 +9,8 @@ import com.github.jasync.sql.db.postgresql.PostgreSQLConnectionBuilder
 import com.github.jasync.sql.db.util.length
 import fr.postgresjson.entity.EntityI
 import fr.postgresjson.serializer.Serializer
+import fr.postgresjson.utils.LoggerDelegate
+import org.slf4j.Logger
 import java.util.concurrent.CompletableFuture
 
 
@@ -31,6 +33,7 @@ class Connection(
 ): Executable {
     private lateinit var connection: ConnectionPool<PostgreSQLConnection>
     private val serializer = Serializer()
+    private val logger: Logger? by LoggerDelegate()
 
     fun connect(): ConnectionPool<PostgreSQLConnection> {
         if (!::connection.isInitialized || !connection.isConnected()) {
@@ -132,6 +135,7 @@ class Connection(
         select(sql, object: TypeReference<List<R>>() {}, values)
 
     override fun exec(sql: String, values: List<Any?>): CompletableFuture<QueryResult> {
+        logger?.debug(sql, values)
         return connect().sendPreparedStatement(sql, compileArgs(values))
     }
 

src/main/kotlin/fr/postgresjson/utils/LoggerDelegate.kt

@@ -0,0 +1,11 @@
+package fr.postgresjson.utils
+
+import org.slf4j.Logger
+import org.slf4j.LoggerFactory
+import kotlin.properties.ReadOnlyProperty
+import kotlin.reflect.KProperty
+
+internal class LoggerDelegate<in R : Any> : ReadOnlyProperty<R, Logger> {
+    override fun getValue(thisRef: R, property: KProperty<*>)
+        = LoggerFactory.getLogger(thisRef.javaClass.packageName)
+}

src/test/resources/logback.xml

@@ -0,0 +1,34 @@
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{YYYY-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
+        </encoder>
+    </appender>
+    <property name="LOG_DIR" value="./postgresjson" />
+    <appender name="query" class="ch.qos.logback.core.FileAppender">
+        <file>${LOG_DIR}/query.log</file>
+        <append>true</append>
+        <encoder>
+            <pattern>%d{YYYY-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{35} - %msg%n</pattern>
+        </encoder>
+    </appender>
+    <appender name="other" class="ch.qos.logback.core.FileAppender">
+        <file>${LOG_DIR}/other.log</file>
+        <append>true</append>
+        <encoder>
+            <pattern>%d{YYYY-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{35} - %msg%n</pattern>
+        </encoder>
+    </appender>
+
+    <root level="trace">
+        <appender-ref ref="STDOUT"/>
+        <appender-ref ref="other" />
+    </root>
+
+    <logger name="org.eclipse.jetty" level="INFO"/>
+    <logger name="io.netty" level="INFO"/>
+
+    <logger name="fr.postgresjson.connexion" level="trace">
+        <appender-ref ref="query" />
+    </logger>
+</configuration>