Use the system configured timezone when formatting logs (linkerd#1833)

Signed-off-by: fantayeneh <[email protected]>

admin/src/main/scala/io/buoyant/admin/TimeZoneLogFormat.scala

@@ -3,9 +3,11 @@ package io.buoyant.admin
 import com.twitter.app.{App => TApp}
 import com.twitter.finagle.tracing.Trace
 import com.twitter.logging.{Level => TwLevel}
-import com.twitter.util.Time
+import com.twitter.util.{Time, TimeFormat}
 import java.util.logging.{Formatter, Level, LogRecord, Logger}
 import java.io.{PrintWriter, StringWriter}
+import java.util.TimeZone
+
 import scala.reflect.NameTransformer
 
 /**
@@ -14,16 +16,17 @@ import scala.reflect.NameTransformer
  */
 
 trait TimeZoneLogFormat { app: TApp =>
+  private val defaultFormat = new TimeFormat(" MMdd HH:mm:ss.SSS z", TimeZone.getDefault)
   premain {
     for (h <- Logger.getLogger("").getHandlers)
-      h.setFormatter(new LogFormatter)
+      h.setFormatter(new LogFormatter(defaultFormat))
   }
 }
 
 /**
  * Implements "glog" style log formatting. Adds a timezone after the timestamp.
  */
-private class LogFormatter extends Formatter {
+private class LogFormatter(timeFormat: TimeFormat) extends Formatter {
   private val levels = Map[Level, Char](
     Level.FINEST -> 'D',
     Level.FINER -> 'D',
@@ -58,7 +61,7 @@ private class LogFormatter extends Formatter {
 
     val str = new StringBuilder(msg.length + 30 + 150)
       .append(levels.getOrElse(r.getLevel, 'U'))
-      .append(Time.fromMilliseconds(r.getMillis).format(" MMdd HH:mm:ss.SSS z"))
+      .append(timeFormat.format(Time.fromMilliseconds(r.getMillis)))
       .append(" THREAD")
       .append(r.getThreadID)
 

admin/src/test/scala/io/buoyant/admin/LogFormatterTest.scala

@@ -0,0 +1,34 @@
+package io.buoyant.admin
+
+import java.util.TimeZone
+import java.util.logging.{Level, LogRecord}
+
+import com.twitter.util.TimeFormat
+import org.scalatest.WordSpec
+
+class LogFormatterTest extends WordSpec {
+
+  val record = new LogRecord(Level.INFO, "Logging useful info")
+  record.setMillis(1519468460239L)
+  record.setThreadID(10)
+
+  "LogFormatter" should {
+
+    "use UTC timezone" in {
+      val utcFormatter = new LogFormatter(
+        new TimeFormat(" MMdd HH:mm:ss.SSS z", TimeZone.getTimeZone("UTC"))
+      )
+      assert(utcFormatter
+        .format(record) == "I 0224 10:34:20.239 UTC THREAD10: Logging useful info\n")
+    }
+
+    "use non UTC timezone" in {
+      val utcFormatter = new LogFormatter(
+        new TimeFormat(" MMdd HH:mm:ss.SSS z", TimeZone.getTimeZone("GMT+8"))
+      )
+      assert(utcFormatter
+        .format(record) == "I 0224 18:34:20.239 GMT+08:00 THREAD10: Logging useful info\n")
+    }
+
+  }
+}