feat(javaagent-log-appender): transfer appender settings to system properties

JavaAgent instrumentation of Log Appenders does not respect logger configs like `log4j2.xml` or `logback.xml`
as it uses direct patching of loggers to do the same and no appenders set in the loggers.

Author: smoke

javaagent-log-appender/build.gradle.kts

@@ -33,11 +33,7 @@ dependencies {
     implementation("io.opentelemetry:opentelemetry-api")
     implementation("io.opentelemetry.semconv:opentelemetry-semconv")
 
-    // OpenTelemetry log4j / logback appenders
-    implementation("io.opentelemetry.instrumentation:opentelemetry-log4j-appender-2.17")
-    implementation("io.opentelemetry.instrumentation:opentelemetry-logback-appender-1.0")
-
-    // OpenTelemetry JavaAgent
+    // OpenTelemetry JavaAgent, this brings its own standalone log4j / logback appenders
     agent("io.opentelemetry.javaagent:opentelemetry-javaagent:2.8.0")
 }
 
@@ -49,5 +45,15 @@ application {
 tasks.named<JavaExec>("run") {
     doFirst {
         jvmArgs("-javaagent:${agent.singleFile}")
+        // log4j-appender properties
+        jvmArgs(
+            "-Dotel.instrumentation.log4j-appender.experimental.capture-map-message-attributes=true",
+            "-Dotel.instrumentation.log4j-appender.experimental-log-attributes=true"
+        )
+        // logback-appender properties
+        jvmArgs(
+            "-Dotel.instrumentation.logback-appender.experimental-log-attributes=true",
+            "-Dotel.instrumentation.logback-appender.experimental.capture-key-value-pair-attributes=true"
+        )
     }
 }

javaagent-log-appender/src/main/resources/log4j2.xml

@@ -1,15 +1,13 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<Configuration status="WARN" packages="io.opentelemetry.instrumentation.log4j.appender.v2_17">
+<Configuration status="WARN">
     <Appenders>
         <Console name="ConsoleAppender" target="SYSTEM_OUT" follow="true">
             <PatternLayout pattern="log4j2: %d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"/>
         </Console>
-        <OpenTelemetry name="OpenTelemetryAppender" captureMapMessageAttributes="true" captureExperimentalAttributes="true"/>
     </Appenders>
     <Loggers>
         <Root level="info">
-            <AppenderRef ref="OpenTelemetryAppender" />
             <AppenderRef ref="ConsoleAppender" />
         </Root>
     </Loggers>
-</Configuration>
+</Configuration>

javaagent-log-appender/src/main/resources/logback.xml

@@ -7,13 +7,7 @@
             </pattern>
         </encoder>
     </appender>
-    <appender name="OpenTelemetry"
-              class="io.opentelemetry.instrumentation.logback.appender.v1_0.OpenTelemetryAppender">
-        <captureExperimentalAttributes>true</captureExperimentalAttributes>
-        <captureKeyValuePairAttributes>true</captureKeyValuePairAttributes>
-    </appender>
     <root level="INFO">
         <appender-ref ref="console"/>
-        <appender-ref ref="OpenTelemetry"/>
     </root>
-</configuration>
+</configuration>