fix: switch from log4j to SLF4J

README.md

@@ -93,11 +93,13 @@ Twilio.setEdge("sydney");
 This will result in the `hostname` transforming from `api.twilio.com` to `api.sydney.au1.twilio.com`.
 
 ### Enable Debug Logging
-In order to enable debug logging, create a configuration file named log4j2.xml that defines the logger at the root level to at least 'debug'. An example of the configuration file can be found [here](src/main/java/com/twilio/example/log4j2.xml). For more configuration options please see the log4j configuration [documentation](https://logging.apache.org/log4j/2.x/manual/configuration.html).
-```java
-Twilio.init(accountSid, authToken);
-Twilio.setLoggerConfiguration("path/to/log4j2.xml");
-```
+
+This library uses SLF4J for logging. Consult the SFL4J documentation
+for information about logging configuration:
+
+  http://slf4j.org/docs.html
+
+For example, if you are using `log4j`, make sure you have `slf4j-log4j12-1.X.XX.jar`, `log4j-1.X.XX.jar` and `slf4j-api-1.X.XX.jar` in your classpath and a `log4j.properties` file in the root of your project.
 
 ### Environment Variables
 

pom.xml

@@ -209,6 +209,11 @@
       <artifactId>jackson-datatype-jsr310</artifactId>
       <version>${jackson.version}</version>
     </dependency>
+    <dependency>
+      <groupId>org.slf4j</groupId>
+      <artifactId>slf4j-api</artifactId>
+      <version>1.7.30</version>
+    </dependency>
     <dependency>
       <groupId>javax.xml.bind</groupId>
       <artifactId>jaxb-api</artifactId>
@@ -231,6 +236,12 @@
       <artifactId>archunit</artifactId>
       <version>0.14.1</version>
       <scope>test</scope>
+      <exclusions>
+        <exclusion>
+          <groupId>org.slf4j</groupId>
+          <artifactId>slf4j-api</artifactId>
+        </exclusion>
+      </exclusions>
     </dependency>
     <dependency>
       <groupId>nl.jqno.equalsverifier</groupId>
@@ -240,13 +251,15 @@
     </dependency>
     <dependency>
       <groupId>org.apache.logging.log4j</groupId>
-      <artifactId>log4j-api</artifactId>
-      <version>2.14.0</version>
-    </dependency>
-    <dependency>
-      <groupId>org.apache.logging.log4j</groupId>
-      <artifactId>log4j-core</artifactId>
+      <artifactId>log4j-slf4j-impl</artifactId>
       <version>2.14.0</version>
+      <scope>test</scope>
+      <exclusions>
+        <exclusion>
+          <groupId>org.slf4j</groupId>
+          <artifactId>slf4j-api</artifactId>
+        </exclusion>
+      </exclusions>
     </dependency>
   </dependencies>
   <build>
@@ -392,4 +405,4 @@
     <artifactId>oss-parent</artifactId>
     <version>7</version>
   </parent>
-</project>
+</project>

src/main/java/com/twilio/Twilio.java

@@ -14,9 +14,6 @@
 import java.util.concurrent.Executors;
 import java.io.File;
 
-import org.apache.logging.log4j.core.LoggerContext;
-import org.apache.logging.log4j.LogManager;
-
 /**
  * Singleton class to initialize Twilio environment.
  */
@@ -154,19 +151,6 @@ public static synchronized void setEdge(final String edge) {
         Twilio.edge = edge;
     }
 
-    /**
-     * Set the logger configuration file path.
-     *
-     * @param filePath path to logging configuration file
-     * @param loggerContext defaults to false to get the appropriate logger context for the caller.
-     */
-    public static synchronized void setLoggerConfiguration(final String filePath, final boolean... loggerContext) {
-        boolean logContext = (loggerContext.length >= 1) ? loggerContext[0] : false;
-        LoggerContext context = (org.apache.logging.log4j.core.LoggerContext) LogManager.getContext(logContext);
-        File file = new File(filePath);
-        context.setConfigLocation(file.toURI());
-    }
-
     /**
      * Returns (and initializes if not initialized) the Twilio Rest Client.
      *

src/main/java/com/twilio/http/TwilioRestClient.java

@@ -3,14 +3,13 @@
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 import java.util.function.Predicate;
 import java.util.Map;
 import java.util.List;
 
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
-import org.apache.logging.log4j.core.LoggerContext;
-
 public class TwilioRestClient {
 
     public static final int HTTP_STATUS_CODE_CREATED = 201;
@@ -25,7 +24,7 @@ public class TwilioRestClient {
     private final String region;
     private final String edge;
     private final HttpClient httpClient;
-    private static final Logger logger = LogManager.getLogger();
+    private static final Logger logger = LoggerFactory.getLogger(TwilioRestClient.class);
 
     private TwilioRestClient(Builder b) {
         this.username = b.username;
@@ -59,11 +58,14 @@ public Response request(final Request request) {
 
         logRequest(request);
         Response response = httpClient.reliableRequest(request);
-        logger.debug("status code: " + response.getStatusCode());
-        org.apache.http.Header[] responseHeaders = response.getHeaders();
-        logger.debug("response headers:");
-        for (int i = 0; i < responseHeaders.length; i++) {
-            logger.debug(responseHeaders[i]);
+
+        if (logger.isDebugEnabled()) {
+            logger.debug("status code: {}", response.getStatusCode());
+            org.apache.http.Header[] responseHeaders = response.getHeaders();
+            logger.debug("response headers:");
+            for (int i = 0; i < responseHeaders.length; i++) {
+                logger.debug("responseHeader: {}", responseHeaders[i]);
+            }
         }
 
         return response;

src/test/java/com/twilio/http/LoggingTest.java

@@ -2,7 +2,6 @@
 
 import com.twilio.Twilio;
 import com.twilio.rest.Domains;
-import com.twilio.rest.api.v2010.account.Message;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.Assert;
@@ -11,8 +10,8 @@
 import java.io.PrintStream;
 
 public class LoggingTest {
+    private static final PrintStream ORIGINAL_SYSTEM_OUT = System.out;
     private ByteArrayOutputStream output;
-    private PrintStream originalStream;
 
     @Before
     public void setUp() throws Exception {
@@ -22,21 +21,19 @@ public void setUp() throws Exception {
     public void logCapturingSetup() {
         output = new ByteArrayOutputStream();
         PrintStream outputStream = new PrintStream(output);
-        originalStream = System.out;
         System.setOut(outputStream);
     }
 
     public void finishLogCapturingSetup(Request request) {
         TwilioRestClient twilioRestClient = Twilio.getRestClient();
         twilioRestClient.logRequest(request);
         System.out.flush();
-        System.setOut(originalStream);
+        System.setOut(ORIGINAL_SYSTEM_OUT);
     }
 
     @Test
     public void testDebugLogging() {
         logCapturingSetup();
-        Twilio.setLoggerConfiguration("src/main/java/com/twilio/example/log4j2.xml");
         final Request request = new Request(HttpMethod.GET, Domains.API.toString(),
                 "/2010-04-01/Accounts/AC123/Messages/MM123.json");
         request.addHeaderParam("Authorization", "authorization value");

src/test/resources/log4j2.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Configuration status="warn" name="MyApp" packages="">
+    <Appenders>
+        <Console name="STDOUT" target="SYSTEM_OUT">
+            <PatternLayout pattern="%d [%t] %-5p %c - %m%n"/>
+        </Console>
+    </Appenders>
+    <Loggers>
+        <Root level="debug">
+            <AppenderRef ref="STDOUT"/>
+        </Root>
+    </Loggers>
+</Configuration>