co.cask.cdap.logging.gateway.handlers.LogDataOffsetCallback.java Source code

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/*
 * Copyright  2016 Cask Data, 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 co.cask.cdap.logging.gateway.handlers;

import ch.qos.logback.classic.spi.ILoggingEvent;
import ch.qos.logback.classic.spi.ThrowableProxyUtil;
import co.cask.cdap.logging.read.LogEvent;
import co.cask.http.HttpResponder;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;

import java.util.List;

/**
 * LogReader callback to encode log events, as {@link LogData} objects.
 */
public class LogDataOffsetCallback extends AbstractJSONCallback {
    private final List<String> fieldsToSuppress;

    LogDataOffsetCallback(HttpResponder responder, List<String> fieldsToSuppress) {
        super(responder);
        this.fieldsToSuppress = fieldsToSuppress;
        validate();
    }

    @Override
    public Object encodeSend(LogEvent logEvent) {
        ILoggingEvent event = logEvent.getLoggingEvent();
        StackTraceElement[] stackTraceElements = event.getCallerData();
        String className = "";
        String simpleClassName = "";
        int lineNumber = 0;
        if (stackTraceElements != null && stackTraceElements.length > 0) {
            StackTraceElement first = stackTraceElements[0];
            className = first.getClassName();
            simpleClassName = (className.indexOf('.') >= 0) ? className.substring(className.lastIndexOf('.') + 1)
                    : className;
            lineNumber = first.getLineNumber();
        }
        LogData logData = new LogData(event.getTimeStamp(), event.getLevel().toString(), event.getThreadName(),
                className, simpleClassName, lineNumber, event.getFormattedMessage(),
                ThrowableProxyUtil.asString(event.getThrowableProxy()));
        return modifyLogJsonElememnt(GSON.toJsonTree(new FormattedLogDataEvent(logData, logEvent.getOffset())));
    }

    private Object modifyLogJsonElememnt(JsonElement jsonElement) {
        JsonObject jsonLogData = (JsonObject) jsonElement;
        JsonObject logData = jsonLogData.getAsJsonObject("log");

        if (!fieldsToSuppress.isEmpty()) {
            for (String field : fieldsToSuppress) {
                logData.remove(field);
            }
        }

        return jsonLogData;
    }

    private void validate() {
        if (fieldsToSuppress.isEmpty()) {
            return;
        }

        for (String fieldToSuppress : fieldsToSuppress) {
            try {
                LogData.class.getDeclaredField(fieldToSuppress);
            } catch (NoSuchFieldException e) {
                throw new IllegalArgumentException(
                        String.format("Field %s is not supported as suppress field", fieldToSuppress));
            }
        }
    }
}