Implementing log_level configuration spec

CHANGELOG.asciidoc

@@ -32,6 +32,8 @@ endif::[]
   This makes it easier to differ distinct snapshot builds of the same version.
   Example: `1.18.1-SNAPSHOT.4655910`
 * Add support for sampling weight with propagation in `tracestate` W3C header {pull}1384[#1384]
+* Adding two more valid options to the `log_level` config: `WARNING` (equivalent to `WARN`) and `CRITICAL`
+  (will be treated as `ERROR`) - {pull}1431[1431]
 
 [float]
 ===== Bug fixes

apm-agent-core/src/main/java/co/elastic/apm/agent/logging/Log4j2ConfigurationFactory.java

@@ -138,7 +138,7 @@ public Configuration getConfiguration() {
         builder.setStatusLevel(Level.ERROR)
             .setConfigurationName("ElasticAPM");
 
-        Level level = Level.valueOf(getValue(LOG_LEVEL_KEY, sources, getValue(DEPRECATED_LOG_LEVEL_KEY, sources, Level.INFO.toString())));
+        Level level = getLogLevel();
         RootLoggerComponentBuilder rootLogger = builder.newRootLogger(level);
         List<AppenderComponentBuilder> appenders = createAppenders(builder);
         for (AppenderComponentBuilder appender : appenders) {
@@ -148,6 +148,12 @@ public Configuration getConfiguration() {
         return builder.build();
     }
 
+    private Level getLogLevel() {
+        String rawLogLevelValue = getValue(LOG_LEVEL_KEY, sources, getValue(DEPRECATED_LOG_LEVEL_KEY, sources, Level.INFO.toString()));
+        LogLevel logLevel = LoggingConfiguration.mapLogLevel(new EnumValueConverter<>(LogLevel.class).convert(rawLogLevelValue));
+        return Level.valueOf(logLevel.toString());
+    }
+
     private List<AppenderComponentBuilder> createAppenders(ConfigurationBuilder<BuiltConfiguration> builder) {
         List<AppenderComponentBuilder> appenders = new ArrayList<>();
         String logFile = getActualLogFile(ElasticApmAgent.getAgentHome(), getValue(LOG_FILE_KEY, sources, getValue(DEPRECATED_LOG_FILE_KEY, sources, DEFAULT_LOG_FILE)));

apm-agent-core/src/main/java/co/elastic/apm/agent/logging/LogLevel.java

@@ -27,7 +27,9 @@
 enum LogLevel {
     OFF,
     ERROR,
+    CRITICAL,
     WARN,
+    WARNING,
     INFO,
     DEBUG,
     TRACE

apm-agent-core/src/main/java/co/elastic/apm/agent/logging/LoggingConfiguration.java

@@ -33,6 +33,7 @@
 import org.stagemonitor.configuration.ConfigurationOptionProvider;
 import org.stagemonitor.configuration.source.ConfigurationSource;
 
+import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 import java.util.List;
 
@@ -77,6 +78,10 @@ public class LoggingConfiguration extends ConfigurationOptionProvider {
      * However, the registry initializes logging by declaring a static final logger variable.
      * In order to break up the cyclic dependency and to not accidentally initialize logging before we had the chance to configure the logging,
      * we manually resolve these options.
+     *
+     * NOTE: on top of the above, this specific option should never be accessed through the ConfigurationOption as it
+     * allows {@link LogLevel} that are effectively mapped to other values.
+     *
      * See {@link Log4j2ConfigurationFactory#getValue}
      */
     @SuppressWarnings("unused")
@@ -85,17 +90,36 @@ public class LoggingConfiguration extends ConfigurationOptionProvider {
         .aliasKeys(DEPRECATED_LOG_LEVEL_KEY)
         .configurationCategory(LOGGING_CATEGORY)
         .description("Sets the logging level for the agent.\n" +
+            "This option is case-insensitive.\n" +
             "\n" +
-            "This option is case-insensitive.")
+            "NOTE: `CRITICAL` is a valid option, but it is mapped to `ERROR`; `WARN` and `WARNING` are equivalent.")
         .dynamic(true)
         .addChangeListener(new ConfigurationOption.ChangeListener<LogLevel>() {
             @Override
             public void onChange(ConfigurationOption<?> configurationOption, LogLevel oldValue, LogLevel newValue) {
+                newValue = mapLogLevel(newValue);
                 setLogLevel(newValue);
             }
         })
         .buildWithDefault(LogLevel.INFO);
 
+    /**
+     * Maps a {@link LogLevel} that is supported by the agent to a value that is also supported by the underlying
+     * logging framework.
+     * @param original the agent-supported {@link LogLevel}
+     * @return a {@link LogLevel} that is both supported by the agent and the underlying logging framework
+     */
+    @Nonnull
+    static LogLevel mapLogLevel(LogLevel original) {
+        LogLevel mapped = original;
+        if (original == LogLevel.WARNING) {
+            mapped = LogLevel.WARN;
+        } else if (original == LogLevel.CRITICAL) {
+            mapped = LogLevel.ERROR;
+        }
+        return mapped;
+    }
+
     @SuppressWarnings("unused")
     public ConfigurationOption<String> logFile = ConfigurationOption.stringOption()
         .key(LOG_FILE_KEY)

apm-agent-plugins/apm-spring-resttemplate-plugin/src/main/java/co/elastic/apm/agent/resttemplate/SpringRestTemplateAdvice.java

@@ -1,3 +1,27 @@
+/*-
+ * #%L
+ * Elastic APM Java agent
+ * %%
+ * Copyright (C) 2018 - 2020 Elastic and contributors
+ * %%
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you 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.
+ * #L%
+ */
 package co.elastic.apm.agent.resttemplate;
 
 import co.elastic.apm.agent.bci.TracerAwareInstrumentation;

docs/configuration.asciidoc

@@ -1514,12 +1514,13 @@ The resulting documents in Elasticsearch look similar to this:
 ==== `log_level`
 
 Sets the logging level for the agent.
-
 This option is case-insensitive.
 
+NOTE: `CRITICAL` is a valid option, but it is mapped to `ERROR`; `WARN` and `WARNING` are equivalent.
+
 <<configuration-dynamic, image:./images/dynamic-config.svg[] >>
 
-Valid options: `OFF`, `ERROR`, `WARN`, `INFO`, `DEBUG`, `TRACE`
+Valid options: `OFF`, `ERROR`, `CRITICAL`, `WARN`, `WARNING`, `INFO`, `DEBUG`, `TRACE`
 
 [options="header"]
 |============
@@ -3054,10 +3055,11 @@ The default unit for this option is `ms`.
 ############################################
 
 # Sets the logging level for the agent.
-# 
 # This option is case-insensitive.
+# 
+# NOTE: `CRITICAL` is a valid option, but it is mapped to `ERROR`; `WARN` and `WARNING` are equivalent.
 #
-# Valid options: OFF, ERROR, WARN, INFO, DEBUG, TRACE
+# Valid options: OFF, ERROR, CRITICAL, WARN, WARNING, INFO, DEBUG, TRACE
 # This setting can be changed at runtime
 # Type: LogLevel
 # Default value: INFO