resolves asciidoctor#536 configure the failure level and fail the tas…

…k accordingly

base/src/main/groovy/org/asciidoctor/gradle/base/process/LoggerSeverity.groovy

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2013-2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.asciidoctor.gradle.base.process
+
+import groovy.transform.CompileStatic
+
+/**
+ * Logging severity (Ruby).
+ */
+@CompileStatic
+enum LoggerSeverity implements Serializable {
+    DEBUG(0),
+    ERROR(3),
+    FATAL(4), // also know as QUIET in ExecutorLogLevel
+    INFO(1),
+    WARN(2),
+
+    final int level
+
+    private LoggerSeverity(int level) {
+        this.level = level
+    }
+
+    static LoggerSeverity of(int level) {
+        for (value in values()) {
+            if (value.level == level) {
+                return value
+            }
+        }
+        return null
+    }
+}

jvm/src/main/groovy/org/asciidoctor/gradle/internal/ExecutorConfiguration.groovy

@@ -17,6 +17,7 @@ package org.asciidoctor.gradle.internal
 
 import groovy.transform.CompileStatic
 import groovy.transform.TupleConstructor
+import org.asciidoctor.gradle.base.process.LoggerSeverity
 
 import java.util.regex.Pattern
 
@@ -53,6 +54,7 @@ class ExecutorConfiguration implements Serializable, Cloneable {
     List<Object> asciidoctorExtensions
 
     ExecutorLogLevel executorLogLevel
+    LoggerSeverity failureLevel
 
     String toString() {
         """backend(s) = ${backendName}

jvm/src/main/groovy/org/asciidoctor/gradle/jvm/AbstractAsciidoctorTask.groovy

@@ -22,6 +22,7 @@ import org.asciidoctor.gradle.base.AbstractAsciidoctorBaseTask
 import org.asciidoctor.gradle.base.AsciidoctorAttributeProvider
 import org.asciidoctor.gradle.base.Transform
 import org.asciidoctor.gradle.base.internal.Workspace
+import org.asciidoctor.gradle.base.process.LoggerSeverity
 import org.asciidoctor.gradle.base.process.ProcessMode
 import org.asciidoctor.gradle.internal.ExecutorConfiguration
 import org.asciidoctor.gradle.internal.ExecutorConfigurationContainer
@@ -69,10 +70,16 @@ class AbstractAsciidoctorTask extends AbstractAsciidoctorBaseTask {
     public final static ProcessMode OUT_OF_PROCESS = ProcessMode.OUT_OF_PROCESS
     public final static ProcessMode JAVA_EXEC = ProcessMode.JAVA_EXEC
 
+    public final static LoggerSeverity FATAL = LoggerSeverity.FATAL
+    public final static LoggerSeverity ERROR = LoggerSeverity.ERROR
+    public final static LoggerSeverity WARN = LoggerSeverity.WARN
+    public final static LoggerSeverity INFO = LoggerSeverity.INFO
+
     protected final static GradleVersion LAST_GRADLE_WITH_CLASSPATH_LEAKAGE = GradleVersion.version(('5.99'))
 
     protected final AsciidoctorJExtension asciidoctorj
     private ProcessMode inProcess = JAVA_EXEC
+    private LoggerSeverity failureLevel = LoggerSeverity.FATAL
     private final WorkerExecutor worker
     private final List<Object> asciidocConfigurations = []
 
@@ -107,6 +114,32 @@ class AbstractAsciidoctorTask extends AbstractAsciidoctorBaseTask {
         this.inProcess
     }
 
+    /** Set the minimum logging level that will fail the task.
+     *
+     * @param severity {@link #FATAL}, {@link #ERROR} or {@link #WARN} or {@link #INFO}.
+     */
+    void setFailureLevel(LoggerSeverity severity) {
+        this.failureLevel = severity
+    }
+
+    /** Set the minimum logging level that will fail the task.
+     *
+     * @param severity Case-insensitive string from of {@link #FATAL}, {@link #ERROR} or {@link #WARN} or {@link #INFO}.
+     */
+    void setFailureLevel(String severity) {
+        this.failureLevel = LoggerSeverity.valueOf(severity.toUpperCase(Locale.US))
+    }
+
+    /** Get the minimum logging level that will fail the task.
+     *
+     * Valid options are {@link #FATAL}, {@link #ERROR} or {@link #WARN} or {@link #INFO}.
+     * The default mode is {@link #FATAL}.
+     */
+    @Internal
+    LoggerSeverity getFailureLevel() {
+        this.failureLevel
+    }
+
     /** Set the mode for running conversions sequential or in parallel.
      * For instance a task that has multiple backends can have the
      * conversion in parallel.
@@ -393,6 +426,7 @@ class AbstractAsciidoctorTask extends AbstractAsciidoctorBaseTask {
             projectDir: project.projectDir,
             rootDir: project.rootProject.projectDir,
             options: evaluateProviders(options),
+            failureLevel: failureLevel,
             attributes: preparePreserialisedAttributes(workingSourceDir, lang),
             backendName: backendName,
             logDocuments: logDocuments,

jvm/src/main/groovy/org/asciidoctor/gradle/remote/AsciidoctorJExecuter.groovy

@@ -21,11 +21,13 @@ import groovy.util.logging.Log4j
 import org.apache.log4j.Level
 import org.apache.log4j.LogManager
 import org.asciidoctor.Asciidoctor
+import org.asciidoctor.gradle.base.process.LoggerSeverity
 import org.asciidoctor.gradle.internal.ExecutorConfiguration
 import org.asciidoctor.gradle.internal.ExecutorConfigurationContainer
 import org.asciidoctor.gradle.internal.ExecutorLogLevel
 import org.asciidoctor.groovydsl.AsciidoctorExtensions
 import org.asciidoctor.log.LogHandler
+import org.gradle.api.GradleException
 
 import javax.inject.Inject
 
@@ -39,6 +41,9 @@ import static org.asciidoctor.jruby.AsciidoctorJRuby.Factory.create
 @Log4j
 class AsciidoctorJExecuter extends ExecutorBase implements Runnable {
 
+    private LoggerSeverity maxSeverity = null
+    private LoggerSeverity failureLevel = null
+
     @Inject
     AsciidoctorJExecuter(
         final ExecutorConfigurationContainer execConfig
@@ -50,12 +55,16 @@ class AsciidoctorJExecuter extends ExecutorBase implements Runnable {
     void run() {
         Thread.currentThread().contextClassLoader = asciidoctorClassLoader
         logLevel = findHighestLogLevel(runConfigurations*.executorLogLevel)
+        failureLevel = findHighestFailureLevel(runConfigurations*.failureLevel)
         logClasspath(Thread.currentThread().contextClassLoader)
         if (runConfigurations.size() == 1) {
             runSingle()
         } else {
             runMultiple()
         }
+        if (failureLevel != null && maxSeverity != null && maxSeverity >= failureLevel) {
+            throw new GradleException("Failure level reached or exceeded: $maxSeverity >= $failureLevel")
+        }
     }
 
     /** Forwards the message to Log4J.
@@ -65,6 +74,9 @@ class AsciidoctorJExecuter extends ExecutorBase implements Runnable {
      */
     @Override
     protected void logMessage(ExecutorLogLevel level, String msg) {
+        if (maxSeverity == null || level.level > maxSeverity.level) {
+            maxSeverity = LoggerSeverity.of(level.level)
+        }
         switch (level) {
             case ExecutorLogLevel.DEBUG:
                 log.debug(msg)
@@ -180,6 +192,11 @@ class AsciidoctorJExecuter extends ExecutorBase implements Runnable {
         this.class.classLoader
     }
 
+    private LoggerSeverity findHighestFailureLevel(Iterable<LoggerSeverity> levels) {
+        int lvl = levels*.level.min() as int
+        LoggerSeverity.of(lvl)
+    }
+
     private ExecutorLogLevel findHighestLogLevel(Iterable<ExecutorLogLevel> levels) {
         int lvl = levels*.level.min() as int
         ExecutorLogLevel.values().find {