Add a custom single-line formatter for java.log.

This logger makes it easier to parse log statements and is now enabled for Bazel's java.log.

RELNOTES[INC]: Bazel now prints logs in single lines to java.log

PiperOrigin-RevId: 152954337

2 files changed, 98 insertions, 0 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/BUILD b/src/main/java/com/google/devtools/build/lib/BUILD
index cd90d661d8..51b444d586 100644
--- a/src/main/java/com/google/devtools/build/lib/BUILD
+++ b/src/main/java/com/google/devtools/build/lib/BUILD
@@ -275,6 +275,15 @@ java_library(
 )
 
 java_library(
+    name = "single-line-formatter",
+    srcs = ["util/SingleLineFormatter.java"],
+    deps = [
+        "//third_party:guava",
+        "//third_party:joda_time",
+    ],
+)
+
+java_library(
     name = "util",
     srcs = glob(
         ["util/*.java"],
@@ -286,6 +295,7 @@ java_library(
             "util/OS.java",
             "util/Preconditions.java",
             "util/ProcessUtils.java",
+            "util/SingleLineFormatter.java",
             "util/StringCanonicalizer.java",
             "util/StringTrie.java",
             "util/VarInt.java",
@@ -1192,6 +1202,7 @@ java_binary(
     main_class = "com.google.devtools.build.lib.bazel.BazelMain",
     runtime_deps = [
         ":bazel-main",
+        ":single-line-formatter",  # See startup_options.cc
     ],
 )
 
diff --git a/src/main/java/com/google/devtools/build/lib/util/SingleLineFormatter.java b/src/main/java/com/google/devtools/build/lib/util/SingleLineFormatter.java
new file mode 100644
index 0000000000..6748917bdc
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/util/SingleLineFormatter.java
@@ -0,0 +1,87 @@
+// Copyright 2017 The Bazel Authors. All rights reserved.
+//
+// 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.google.devtools.build.lib.util;
+
+import com.google.common.collect.ImmutableRangeMap;
+import com.google.common.collect.Range;
+import java.io.PrintWriter;
+import java.io.StringWriter;
+import java.util.logging.Formatter;
+import java.util.logging.Level;
+import java.util.logging.LogRecord;
+import org.joda.time.format.DateTimeFormat;
+import org.joda.time.format.DateTimeFormatter;
+
+/**
+ * Formatter to write java.util.logging messages out in single-line format.
+ *
+ * <p>Log entries contain the date and time (in UTC), log level (as letter and numerical value),
+ * source location, thread ID, message and, if applicable, a stack trace.
+ */
+public class SingleLineFormatter extends Formatter {
+
+  /** Single-character codes based on {@link Level}s. */
+  private static final ImmutableRangeMap<Integer, Character> CODES_BY_LEVEL =
+      ImmutableRangeMap.<Integer, Character>builder()
+          .put(Range.atMost(Level.FINE.intValue()), 'D')
+          .put(Range.open(Level.FINE.intValue(), Level.WARNING.intValue()), 'I')
+          .put(Range.closedOpen(Level.WARNING.intValue(), Level.SEVERE.intValue()), 'W')
+          .put(Range.atLeast(Level.SEVERE.intValue()), 'X')
+          .build();
+
+  /** A thread safe, immutable formatter that can be used by all without contention. */
+  private static final DateTimeFormatter DATE_TIME_FORMAT =
+      DateTimeFormat.forPattern("yyMMdd HH:mm:ss.SSS").withZoneUTC();
+
+  @Override
+  public String format(LogRecord rec) {
+    StringBuilder buf = new StringBuilder();
+
+    // Timestamp
+    buf.append(DATE_TIME_FORMAT.print(rec.getMillis()))
+        .append(':');
+
+    // One character code for level
+    buf.append(CODES_BY_LEVEL.get(rec.getLevel().intValue()));
+
+    // The stack trace, if any
+    Throwable thrown = rec.getThrown();
+    if (thrown != null) {
+      buf.append('T');
+    }
+
+    buf.append(' ');
+
+    // Information about the source of the exception
+    buf.append(rec.getThreadID())
+        .append(" [")
+        .append(rec.getSourceClassName())
+        .append('.')
+        .append(rec.getSourceMethodName())
+        .append("] ");
+
+    // The actual message
+    buf.append(formatMessage(rec)).append('\n');
+
+    if (thrown != null) {
+      StringWriter sw = new StringWriter();
+      PrintWriter pw = new PrintWriter(sw);
+      thrown.printStackTrace(pw);
+      pw.flush();
+      buf.append(sw.toString());
+    }
+
+    return buf.toString();
+  }
+}