1 files changed, 142 insertions, 0 deletions
diff --git a/common/openecomp-logging-lib/openecomp-logging-core/src/main/java/org/openecomp/core/logging/logback/DispatchingAppender.java b/common/openecomp-logging-lib/openecomp-logging-core/src/main/java/org/openecomp/core/logging/logback/DispatchingAppender.java
new file mode 100644
index 0000000000..6d5642e374
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+++ b/common/openecomp-logging-lib/openecomp-logging-core/src/main/java/org/openecomp/core/logging/logback/DispatchingAppender.java
@@ -0,0 +1,142 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * SDC
+ * ================================================================================
+ * Copyright (C) 2017 AT&T Intellectual Property. All rights reserved.
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.openecomp.core.logging.logback;
+
+import ch.qos.logback.classic.Logger;
+import ch.qos.logback.classic.LoggerContext;
+import ch.qos.logback.classic.sift.MDCBasedDiscriminator;
+import ch.qos.logback.classic.spi.ILoggingEvent;
+import ch.qos.logback.core.Appender;
+import ch.qos.logback.core.AppenderBase;
+import ch.qos.logback.core.joran.spi.DefaultClass;
+import ch.qos.logback.core.sift.Discriminator;
+import org.slf4j.LoggerFactory;
+
+import java.util.Iterator;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+/**
+ * <p>Allows to use EELF logging configuration almost as is, by using a custom routing function, but
+ * pre-configured appenders attached to the standard EELF loggers.</p> <p>Changes that must be made
+ * in <i>logback.xml</i> supplied with EELF:</p>
+ * <pre>
+ *     &lt;appender name="DISPATCHER" class="DispatchingAppender"&gt;
+ *          &lt;discriminator class="EventTypeDiscriminator"/&gt;
+ *          &lt;appenderNamePattern&gt;asyncEELF%s&lt;/appenderNamePattern&gt;
+ *     &lt;/appender&gt;
+ *     &lt;root level="INFO" additivity="false"&gt;
+ *          &lt;appender-ref ref="DISPATCHER" /&gt;
+ *      &lt;/root&gt;
+ * </pre>
+ */
+public class DispatchingAppender extends AppenderBase<ILoggingEvent> {
+
+  // "magic" appender to indicate a missing appender
+  private static final Appender<ILoggingEvent> NO_APPENDER = new DispatchingAppender();
+
+  private Map<String, Appender<ILoggingEvent>> appenders = new ConcurrentHashMap<>();
+
+  private Discriminator<ILoggingEvent> discriminator;
+  private String appenderNamePattern;
+
+  public Discriminator<ILoggingEvent> getDiscriminator() {
+    return this.discriminator;
+  }
+
+  @DefaultClass(MDCBasedDiscriminator.class)
+  public void setDiscriminator(Discriminator<ILoggingEvent> discriminator) {
+    this.discriminator = discriminator;
+  }
+
+  public String getAppenderNamePattern() {
+    return this.appenderNamePattern;
+  }
+
+  public void setAppenderNamePattern(String pattern) {
+    this.appenderNamePattern = pattern;
+  }
+
+  @Override
+  protected void append(ILoggingEvent event) {
+
+    if (this.isStarted()) {
+
+      String discriminatingValue = this.discriminator.getDiscriminatingValue(event);
+      String appenderName = String.format(this.appenderNamePattern, discriminatingValue);
+      Appender<ILoggingEvent> appender = this.lookupAppender(appenderName);
+      if (appender == NO_APPENDER) {
+        this.addError(String.format("Appender %s does not exist", appenderName));
+      } else {
+        appender.doAppend(event);
+      }
+    }
+  }
+
+  private Appender<ILoggingEvent> lookupAppender(String key) {
+
+    Appender<ILoggingEvent> appender = appenders.get(key);
+    if (appender != null) {
+      return appender;
+    }
+
+    LoggerContext context = (LoggerContext) LoggerFactory.getILoggerFactory();
+    for (Logger log : context.getLoggerList()) {
+
+      Iterator<Appender<ILoggingEvent>> iterator = log.iteratorForAppenders();
+      while (iterator.hasNext()) {
+
+        Appender<ILoggingEvent> element = iterator.next();
+        if (key.equals(element.getName())) {
+          this.appenders.putIfAbsent(key, element);
+          return element;
+        }
+      }
+    }
+
+    // to avoid consecutive lookups if the required appender does not exist
+    this.appenders.putIfAbsent(key, NO_APPENDER);
+    return NO_APPENDER;
+  }
+
+  @Override
+  public void start() {
+
+    int errors = 0;
+    if (this.discriminator == null) {
+      this.addError("Missing discriminator. Aborting");
+    }
+
+    if (!this.discriminator.isStarted()) {
+      this.addError("Discriminator has not started successfully. Aborting");
+      ++errors;
+    }
+
+    if (this.appenderNamePattern == null) {
+      this.addError("Missing name pattern. Aborting");
+      ++errors;
+    }
+
+    if (errors == 0) {
+      super.start();
+    }
+  }
+}