com.visionarts.powerjambda.logging.LambdaLoggerHelper Maven / Gradle / Ivy

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/*
 * Copyright 2017 the original author or authors.
 *
 * 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.visionarts.powerjambda.logging;

import java.util.Arrays;
import java.util.List;
import java.util.Objects;
import java.util.Optional;

import com.amazonaws.services.lambda.runtime.Context;
import com.visionarts.powerjambda.ApiGatewayRequestContext;
import com.visionarts.powerjambda.ApiGatewayRequestIdentity;
import com.visionarts.powerjambda.AwsProxyRequest;
import org.apache.logging.log4j.Level;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.ThreadContext;
import org.apache.logging.log4j.core.LoggerContext;
import org.apache.logging.log4j.core.config.Configuration;
import org.apache.logging.log4j.core.config.LoggerConfig;

/**
 * Helper class that operates for the logger on lambda framework.
 *
 */
public class LambdaLoggerHelper {

    private static final Logger logger = LogManager.getLogger(LambdaLoggerHelper.class);
    private static final String LOG_LEVEL_ENV_VAR_KEY = "LOG_LEVEL";
    private static final Level DEFAULT_LOG_LEVEL = Level.INFO;
    private static final List DEFAULT_LOGGING_HEADERS = Arrays.asList(
            "X-Amz-Cf-Id",
            "X-Amzn-Trace-Id");

    static {
        Optional logLevelEnv = Optional.ofNullable(System.getenv(LOG_LEVEL_ENV_VAR_KEY));
        Level logLevel = logLevelEnv.map(rawVal -> {
            Level level = Level.toLevel(rawVal, DEFAULT_LOG_LEVEL);
            logger.info("Overriding the log level for log4j 2. Environment variable {} has value: \'{}\' ({})",
                    LOG_LEVEL_ENV_VAR_KEY, level, rawVal);
            return level;
        }).orElse(DEFAULT_LOG_LEVEL);
        updateLevel(logLevel);
    }

    // Suppresses default constructor, ensuring non-instantiability.
    private LambdaLoggerHelper() {
    }

    public static void clear() {
        ThreadContext.clearAll();
    }

    public static void putThreadContext(AwsProxyRequest request) {
        putThreadContext(request, DEFAULT_LOGGING_HEADERS);
    }

    public static void putThreadContext(AwsProxyRequest request, List loggingHeaders) {
        List availableLoggingHeaders = Objects.requireNonNull(loggingHeaders);
        Optional.ofNullable(request.getRequestContext())
            .map(ApiGatewayRequestContext::getIdentity)
            .map(ApiGatewayRequestIdentity::getSourceIp)
            .ifPresent(ip -> ThreadContext.put("sourceIp", ip));
        Optional.ofNullable(request.getHeaders())
            .ifPresent(headers -> availableLoggingHeaders.forEach(
                headerKey -> putIfNotNullValue(headerKey, headers.get(headerKey))));
    }

    public static void putThreadContext(Context context) {
        if (!ThreadContext.containsKey("AWSRequestId")) {
            // AWS Lambda does not put request id to MDC at cold start,
            // so put it myself
            ThreadContext.put("AWSRequestId", context.getAwsRequestId());
        }
        ThreadContext.put("version", context.getFunctionVersion());
    }

    private static void putIfNotNullValue(String key, String value) {
        Optional.ofNullable(value).ifPresent(v -> ThreadContext.put(key, v));
    }

    private static void updateLevel(Level level) {
        LoggerContext ctx = (LoggerContext) LogManager.getContext(false);
        Configuration config = ctx.getConfiguration();
        LoggerConfig loggerConfig = config.getLoggerConfig(LogManager.ROOT_LOGGER_NAME);
        Level curLevel = loggerConfig.getLevel();
        if (curLevel != level) {
            loggerConfig.setLevel(level);
            ctx.updateLoggers();
        }
    }
}