chore: add logging to driver installation (#865)

driver/src/main/java/com/microsoft/playwright/impl/Driver.java

@@ -18,8 +18,11 @@ package com.microsoft.playwright.impl;
 
 import java.nio.file.Path;
 import java.nio.file.Paths;
+import java.time.ZonedDateTime;
 import java.util.Map;
 
+import static com.microsoft.playwright.impl.DriverLogging.logWithTimestamp;
+
 /**
  * This class provides access to playwright-cli. It can be either preinstalled
  * in the host system and its path is passed as a system property or it can be
@@ -31,6 +34,7 @@ public abstract class Driver {
   private static class PreinstalledDriver extends Driver {
     private final Path driverDir;
     PreinstalledDriver(Path driverDir) {
+      logMessage("created PreinstalledDriver: " + driverDir);
       this.driverDir = driverDir;
     }
 
@@ -49,7 +53,9 @@ public abstract class Driver {
     if (instance == null) {
       try {
         instance = createDriver();
+        logMessage("initializing driver");
         instance.initialize(env, installBrowsers);
+        logMessage("driver inialized.");
       } catch (Exception exception) {
         throw new RuntimeException("Failed to create driver", exception);
       }
@@ -97,4 +103,9 @@ public abstract class Driver {
   }
 
   abstract Path driverDir();
+
+  protected static void logMessage(String message) {
+    // This matches log format produced by the server.
+    logWithTimestamp("pw:install " + message);
+  }
 }

driver/src/main/java/com/microsoft/playwright/impl/DriverLogging.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) Microsoft Corporation.
+ *
+ * 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.
+ */
+
+package com.microsoft.playwright.impl;
+
+import java.time.ZoneId;
+import java.time.ZonedDateTime;
+import java.time.format.DateTimeFormatter;
+
+class DriverLogging {
+  private static final boolean isEnabled;
+  static {
+    String debug = System.getenv("DEBUG");
+    isEnabled = (debug != null) && debug.contains("pw:install");
+  }
+
+  private static final DateTimeFormatter timestampFormat = DateTimeFormatter.ofPattern(
+    "yyyy-MM-dd'T'HH:mm:ss.SSSXXX").withZone(ZoneId.of("UTC"));
+
+  static void logWithTimestamp(String message) {
+    // This matches log format produced by the server.
+    String timestamp = ZonedDateTime.now().format(timestampFormat);
+    System.err.println(timestamp + " " + message);
+  }
+}