com.facebook.buck.log.ConsoleHandler.java Source code

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Here is the source code for com.facebook.buck.log.ConsoleHandler.java

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/*
 * Copyright 2014-present Facebook, Inc.
 *
 * 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.facebook.buck.log;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Iterables;

import java.io.IOError;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;
import java.util.logging.Formatter;
import java.util.logging.Handler;
import java.util.logging.Level;
import java.util.logging.LogManager;
import java.util.logging.LogRecord;

import javax.annotation.concurrent.GuardedBy;

/**
 * Implementation of Handler which writes to the console (System.err by default).
 */
public class ConsoleHandler extends Handler {
    private static final Level DEFAULT_LEVEL = Level.SEVERE;

    private final ConsoleHandlerState.Writer defaultOutputStreamWriter;
    private final ConsoleHandlerState state;

    @GuardedBy("this")
    private boolean closed;

    public ConsoleHandler() {
        this(utf8OutputStreamWriter(System.err), new LogFormatter(),
                getLogLevelFromProperty(LogManager.getLogManager(), DEFAULT_LEVEL),
                GlobalStateManager.singleton().getConsoleHandlerState());
    }

    @VisibleForTesting
    ConsoleHandler(ConsoleHandlerState.Writer defaultOutputStreamWriter, Formatter formatter, Level level,
            ConsoleHandlerState state) {
        this.defaultOutputStreamWriter = defaultOutputStreamWriter;
        setFormatter(formatter);
        setLevel(level);
        this.state = state;
    }

    @Override
    public void publish(LogRecord record) {
        synchronized (this) {
            if (closed || !(isLoggable(record) || isLoggableWithRegisteredLogLevel(record))
                    || isBlacklisted(record)) {
                return;
            }
        }

        Iterable<ConsoleHandlerState.Writer> outputStreamWriters = getOutputStreamWritersForRecord(record);

        try {
            String formatted = getFormatter().format(record);

            for (ConsoleHandlerState.Writer outputStreamWriter : outputStreamWriters) {
                synchronized (outputStreamWriter) {
                    outputStreamWriter.write(formatted);
                    if (record.getLevel().intValue() >= Level.SEVERE.intValue()) {
                        outputStreamWriter.flush();
                    }
                }
            }
        } catch (IOException e) {
            throw new IOError(e);
        }
    }

    @Override
    public void close() {
        synchronized (this) {
            if (!closed) {
                flush();
                // We explicitly do not close any registered writers, so we don't close
                // System.err accidentally.
                closed = true;
            }
        }
    }

    @Override
    public void flush() {
        synchronized (this) {
            if (closed) {
                return;
            }
        }

        try {
            for (ConsoleHandlerState.Writer outputStreamWriter : state.getAllAvailableWriters()) {
                synchronized (outputStreamWriter) {
                    outputStreamWriter.flush();
                }
            }
            synchronized (defaultOutputStreamWriter) {
                defaultOutputStreamWriter.flush();
            }
        } catch (IOException e) {
            throw new IOError(e);
        }
    }

    private static Level getLogLevelFromProperty(LogManager logManager, Level defaultLevel) {
        String levelStr = logManager.getProperty(ConsoleHandler.class.getName() + ".level");
        if (levelStr != null) {
            return Level.parse(levelStr);
        } else {
            return defaultLevel;
        }
    }

    public static ConsoleHandlerState.Writer utf8OutputStreamWriter(OutputStream outputStream) {
        try {
            final OutputStreamWriter outputStreamWriter = new OutputStreamWriter(outputStream, "UTF-8");
            return new ConsoleHandlerState.Writer() {
                @Override
                public void write(String line) throws IOException {
                    outputStreamWriter.write(line);
                }

                @Override
                public void flush() throws IOException {
                    outputStreamWriter.flush();
                }

                @Override
                public void close() throws IOException {
                    outputStreamWriter.close();
                }
            };
        } catch (UnsupportedEncodingException e) {
            throw new IOError(e);
        }
    }

    private boolean isLoggableWithRegisteredLogLevel(LogRecord record) {
        long recordThreadId = record.getThreadID();
        String logRecordCommandId = state.threadIdToCommandId(recordThreadId);
        if (logRecordCommandId == null) {
            // An unregistered thread created this LogRecord, so we don't want to force logging it.
            return false;
        }
        Level commandIdLogLevel = state.getLogLevel(logRecordCommandId);
        if (commandIdLogLevel == null) {
            // No log level override registered for this command ID. Don't force logging it.
            return false;
        }

        // Level.ALL.intValue() is Integer.MIN_VALUE, so have to compare it explicitly.
        return commandIdLogLevel.equals(Level.ALL) || commandIdLogLevel.intValue() >= record.getLevel().intValue();
    }

    private boolean isBlacklisted(LogRecord record) {
        // Guava futures internals are not very actionable to the user but we still want to have
        // them in the log.
        return record.getLoggerName() != null
                && record.getLoggerName().startsWith("com.google.common.util.concurrent");
    }

    private Iterable<ConsoleHandlerState.Writer> getOutputStreamWritersForRecord(LogRecord record) {
        long recordThreadId = record.getThreadID();
        String logRecordCommandId = state.threadIdToCommandId(recordThreadId);
        if (logRecordCommandId != null) {
            ConsoleHandlerState.Writer consoleWriter = state.getWriter(logRecordCommandId);
            if (consoleWriter != null) {
                return ImmutableSet.of(consoleWriter);
            } else {
                return ImmutableSet.of(defaultOutputStreamWriter);
            }
        } else {
            Iterable<ConsoleHandlerState.Writer> allConsoleWriters = state.getAllAvailableWriters();
            if (Iterables.isEmpty(allConsoleWriters)) {
                return ImmutableSet.of(defaultOutputStreamWriter);
            } else {
                ImmutableSet.Builder<ConsoleHandlerState.Writer> builder = ImmutableSet.builder();
                builder.addAll(allConsoleWriters);
                return builder.build();
            }
        }
    }
}