Migrate httpd classes to Flogger

This is the first part of the migration to Flogger. This change
migrates all classes of the 'http' module to Flogger. Other modules
continue to use slf4j. They should be migrated by follow-up changes.

During this migration we try to make the log statements more consistent:
- avoid string concatenation
- avoid usage of String.format(...)

Change-Id: I473c41733b00aa1ceab92fe0dc8cd1c6b347174c
Signed-off-by: Edwin Kempin <ekempin@google.com>

java/com/google/gerrit/httpd/plugins/HttpPluginServlet.java

@@ -32,6 +32,7 @@ import com.google.common.base.Strings;
 import com.google.common.cache.Cache;
 import com.google.common.collect.Lists;
 import com.google.common.collect.Maps;
+import com.google.common.flogger.FluentLogger;
 import com.google.common.io.ByteStreams;
 import com.google.common.net.HttpHeaders;
 import com.google.gerrit.extensions.registration.RegistrationHandle;
@@ -92,14 +93,13 @@ import org.apache.commons.lang.StringUtils;
 import org.eclipse.jgit.lib.Config;
 import org.eclipse.jgit.util.IO;
 import org.eclipse.jgit.util.RawParseUtils;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 @Singleton
 class HttpPluginServlet extends HttpServlet implements StartPluginListener, ReloadPluginListener {
+  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
+
   private static final int SMALL_RESOURCE = 128 * 1024;
   private static final long serialVersionUID = 1L;
-  private static final Logger log = LoggerFactory.getLogger(HttpPluginServlet.class);
 
   private final MimeUtilFileTypeRegistry mimeUtil;
   private final Provider<String> webUrl;
@@ -191,7 +191,7 @@ class HttpPluginServlet extends HttpServlet implements StartPluginListener, Relo
       try {
         filter = plugin.getHttpInjector().getInstance(GuiceFilter.class);
       } catch (RuntimeException e) {
-        log.warn("Plugin {} cannot load GuiceFilter", name, e);
+        logger.atWarning().withCause(e).log("Plugin %s cannot load GuiceFilter", name);
         return null;
       }
 
@@ -199,7 +199,7 @@ class HttpPluginServlet extends HttpServlet implements StartPluginListener, Relo
         ServletContext ctx = PluginServletContext.create(plugin, wrapper.getFullPath(name));
         filter.init(new WrappedFilterConfig(ctx));
       } catch (ServletException e) {
-        log.warn("Plugin {} failed to initialize HTTP", name, e);
+        logger.atWarning().withCause(e).log("Plugin %s failed to initialize HTTP", name);
         return null;
       }
 
@@ -423,12 +423,12 @@ class HttpPluginServlet extends HttpServlet implements StartPluginListener, Relo
               && (name.endsWith(".md") || name.endsWith(".html"))
               && size.isPresent()) {
             if (size.get() <= 0 || size.get() > SMALL_RESOURCE) {
-              log.warn(
-                  "Plugin {}: {} omitted from document index. Size {} out of range (0,{}).",
-                  pluginName,
-                  name.substring(prefix.length()),
-                  size.get(),
-                  SMALL_RESOURCE);
+              logger
+                  .atWarning()
+                  .log(
+                      "Plugin %s: %s omitted from document index. "
+                          + "Size %d out of range (0,%d).",
+                      pluginName, name.substring(prefix.length()), size.get(), SMALL_RESOURCE);
               return false;
             }
             return true;
@@ -450,10 +450,11 @@ class HttpPluginServlet extends HttpServlet implements StartPluginListener, Relo
         if (about == null) {
           about = entry;
         } else {
-          log.warn(
-              "Plugin {}: Multiple 'about' documents found; using {}",
-              pluginName,
-              about.getName().substring(prefix.length()));
+          logger
+              .atWarning()
+              .log(
+                  "Plugin %s: Multiple 'about' documents found; using %s",
+                  pluginName, about.getName().substring(prefix.length()));
         }
       } else {
         docs.add(entry);
@@ -731,7 +732,10 @@ class HttpPluginServlet extends HttpServlet implements StartPluginListener, Relo
         }
         return def;
       } catch (IOException e) {
-        log.warn("Error getting {} for plugin {}, using default", attr, plugin.getName(), e);
+        logger
+            .atWarning()
+            .withCause(e)
+            .log("Error getting %s for plugin %s, using default", attr, plugin.getName());
         return null;
       }
     }

java/com/google/gerrit/httpd/plugins/LfsPluginServlet.java

@@ -18,6 +18,7 @@ import static com.google.gerrit.extensions.api.lfs.LfsDefinitions.CONTENTTYPE_VN
 import static java.nio.charset.StandardCharsets.UTF_8;
 import static javax.servlet.http.HttpServletResponse.SC_NOT_IMPLEMENTED;
 
+import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.extensions.registration.RegistrationHandle;
 import com.google.gerrit.httpd.resources.Resource;
 import com.google.gerrit.server.config.GerritServerConfig;
@@ -45,14 +46,14 @@ import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import org.eclipse.jgit.lib.Config;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 @Singleton
 public class LfsPluginServlet extends HttpServlet
     implements StartPluginListener, ReloadPluginListener {
   private static final long serialVersionUID = 1L;
-  private static final Logger log = LoggerFactory.getLogger(LfsPluginServlet.class);
+
+  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
+
   private static final String MESSAGE_LFS_NOT_CONFIGURED =
       "{\"message\":\"No LFS plugin is configured to handle LFS requests.\"}";
 
@@ -139,7 +140,7 @@ public class LfsPluginServlet extends HttpServlet
       try {
         guiceFilter = plugin.getHttpInjector().getInstance(GuiceFilter.class);
       } catch (RuntimeException e) {
-        log.warn("Plugin {} cannot load GuiceFilter", name, e);
+        logger.atWarning().withCause(e).log("Plugin %s cannot load GuiceFilter", name);
         return null;
       }
 
@@ -147,7 +148,7 @@ public class LfsPluginServlet extends HttpServlet
         ServletContext ctx = PluginServletContext.create(plugin, "/");
         guiceFilter.init(new WrappedFilterConfig(ctx));
       } catch (ServletException e) {
-        log.warn("Plugin {} failed to initialize HTTP", name, e);
+        logger.atWarning().withCause(e).log("Plugin %s failed to initialize HTTP", name);
         return null;
       }
 

java/com/google/gerrit/httpd/plugins/PluginServletContext.java

@@ -15,6 +15,7 @@
 package com.google.gerrit.httpd.plugins;
 
 import com.google.common.collect.Maps;
+import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.common.Version;
 import com.google.gerrit.server.plugins.Plugin;
 import java.io.InputStream;
@@ -29,11 +30,9 @@ import java.util.concurrent.ConcurrentMap;
 import javax.servlet.RequestDispatcher;
 import javax.servlet.Servlet;
 import javax.servlet.ServletContext;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 class PluginServletContext {
-  private static final Logger log = LoggerFactory.getLogger(PluginServletContext.class);
+  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
 
   static ServletContext create(Plugin plugin, String contextPath) {
     return (ServletContext)
@@ -155,7 +154,7 @@ class PluginServletContext {
 
     @Override
     public void log(String msg, Throwable reason) {
-      log.warn("[plugin {}] {}", plugin.getName(), msg, reason);
+      logger.atWarning().withCause(reason).log("[plugin %s] %s", plugin.getName(), msg);
     }
 
     @Override