Improve library usage of slf4j and logback.

Logback-classic is now a test dependency and is additionally declared as OPTIONAL runtime dependency.
Applications that don't want to use logback can now easily disable it by not explicitly depending on it.

build.gradle

@@ -65,6 +65,7 @@ allprojects {
 
     project.ext {
         slf4jVersion = '1.7.32'
+        logbackVersion = '1.2.6'
         junitVersion = '5.7.2'
         picocliVersion = '4.6.1'
         rootConfigDir = new File(rootDir, 'config')

pgpainless-cli/build.gradle

@@ -33,16 +33,17 @@ dependencies {
     testRuntimeOnly "org.junit.jupiter:junit-jupiter-engine:$junitVersion"
     // https://todd.ginsberg.com/post/testing-system-exit/
     testImplementation 'com.ginsberg:junit5-system-exit:1.1.1'
-    // We want logback logging in tests
-    testImplementation 'ch.qos.logback:logback-classic:1.2.5'
+
+    // implementation "ch.qos.logback:logback-core:1.2.6"
+    // We want logback logging in tests and in the app
+    testImplementation "ch.qos.logback:logback-classic:$logbackVersion"
+    implementation "ch.qos.logback:logback-classic:$logbackVersion"
 
     implementation(project(":pgpainless-sop"))
     implementation(project(":sop-java"))
     implementation(project(":sop-java-picocli"))
 
     implementation "info.picocli:picocli:$picocliVersion"
-    // We don't want logging in the application itself
-    implementation "org.slf4j:slf4j-nop:$slf4jVersion"
 
     // https://mvnrepository.com/artifact/com.google.code.findbugs/jsr305
     implementation group: 'com.google.code.findbugs', name: 'jsr305', version: '3.0.2'

pgpainless-cli/src/main/resources/logback.xml

@@ -4,15 +4,23 @@ SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
 SPDX-License-Identifier: Apache-2.0
 -->
 
-<configuration>
+<configuration debug="false">
     <appender name="STDERR" class="ch.qos.logback.core.ConsoleAppender">
         <target>System.err</target>
         <encoder>
-            <pattern>%blue(%-5level) %green(%logger{35}) - %msg %n</pattern>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
         </encoder>
     </appender>
 
-    <logger name="org.apache" level="INFO ">
-        <appender-ref ref="STDERR"/>
-    </logger>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <target>System.out</target>
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
+        </encoder>
+    </appender>
+
+    <root level="error">
+        <appender-ref ref="STDERR" />
+    </root>
+
 </configuration>

pgpainless-cli/src/test/resources/logback-test.xml

@@ -0,0 +1,25 @@
+<!--
+SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
+
+SPDX-License-Identifier: Apache-2.0
+-->
+
+<configuration debug="false">
+    <appender name="STDERR" class="ch.qos.logback.core.ConsoleAppender">
+        <target>System.err</target>
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
+        </encoder>
+    </appender>
+
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <target>System.out</target>
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
+        </encoder>
+    </appender>
+
+    <root level="error">
+        <appender-ref ref="STDERR" />
+    </root>
+</configuration>

pgpainless-core/build.gradle

@@ -10,9 +10,11 @@ dependencies {
     testImplementation "org.junit.jupiter:junit-jupiter-api:$junitVersion"
     testImplementation "org.junit.jupiter:junit-jupiter-params:$junitVersion"
     testRuntimeOnly "org.junit.jupiter:junit-jupiter-engine:$junitVersion"
-    testImplementation 'ch.qos.logback:logback-classic:1.2.5'
 
+    // Logging
     api "org.slf4j:slf4j-api:$slf4jVersion"
+    testImplementation "ch.qos.logback:logback-classic:$logbackVersion"
+    runtime "ch.qos.logback:logback-classic:$logbackVersion"
 
     api "org.bouncycastle:bcprov-jdk15on:$bouncyCastleVersion"
     api "org.bouncycastle:bcpg-jdk15on:$bouncyCastleVersion"

pgpainless-core/src/main/resources/logback.xml

@@ -1,18 +0,0 @@
-<!--
-SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-
-SPDX-License-Identifier: Apache-2.0
--->
-
-<configuration>
-    <appender name="STDERR" class="ch.qos.logback.core.ConsoleAppender">
-        <target>System.err</target>
-        <encoder>
-            <pattern>%blue(%-5level) %green(%logger{35}) - %msg %n</pattern>
-        </encoder>
-    </appender>
-
-    <logger name="org.apache" level="INFO ">
-        <appender-ref ref="STDERR"/>
-    </logger>
-</configuration>

pgpainless-core/src/test/resources/logback-test.xml

@@ -0,0 +1,29 @@
+<!--
+SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
+
+SPDX-License-Identifier: Apache-2.0
+-->
+
+<configuration debug="false">
+    <appender name="STDERR" class="ch.qos.logback.core.ConsoleAppender">
+        <target>System.err</target>
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
+        </encoder>
+    </appender>
+
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <target>System.out</target>
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
+        </encoder>
+    </appender>
+
+    <logger name="org.pgpainless" level="warn" additivity="false">
+        <appender-ref ref="STDOUT" />
+    </logger>
+
+    <root level="error">
+        <appender-ref ref="STDERR" />
+    </root>
+</configuration>

pgpainless-sop/build.gradle

@@ -13,10 +13,12 @@ repositories {
 }
 
 dependencies {
-    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.7.0'
-    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.7.0'
+    testImplementation "org.junit.jupiter:junit-jupiter-api:$junitVersion"
+    testRuntimeOnly "org.junit.jupiter:junit-jupiter-engine:$junitVersion"
 
-    testImplementation 'ch.qos.logback:logback-classic:1.2.5'
+    // Logging
+    testImplementation "ch.qos.logback:logback-classic:$logbackVersion"
+    runtime "ch.qos.logback:logback-classic:$logbackVersion"
 
     implementation(project(":pgpainless-core"))
     implementation(project(":sop-java"))

sop-java-picocli/build.gradle

@@ -9,6 +9,7 @@ plugins {
 dependencies {
     testImplementation "org.junit.jupiter:junit-jupiter-api:$junitVersion"
     testRuntimeOnly "org.junit.jupiter:junit-jupiter-engine:$junitVersion"
+
     // https://todd.ginsberg.com/post/testing-system-exit/
     testImplementation 'com.ginsberg:junit5-system-exit:1.1.1'
     testImplementation "org.mockito:mockito-core:3.11.2"