const zlib = require("zlib");
const aws = require("aws-sdk");
const sns = new aws.SNS({
    apiVersion: "2010-03-31",
    region: 'ap-northeast-1'
});

exports.handler = function(input, context) {
    var payload = new Buffer.from(input.awslogs.data, 'base64');
    zlib.gunzip(payload, function(e, result) {
        if (e) {
            context.fail(e);
        } else {
            result = JSON.parse(result.toString('UTF-8'));
            const publishMessage = {
                Subject: `Detect Error(or Warning) in ${result.logGroup}`,
                Message: result.logEvents.map((l) => l.message).join('\n'),
                TopicArn: process.env.topicArn
            };
            console.log(publishMessage);

            sns.publish(publishMessage, (err, data) => {
                console.log(err, data);
                if(err){
                    context.fail(err);
                }
            });
        }
    });
};