AWS CodePipeline与GitHub集成

const AWS = require('aws-sdk');
const axios = require('axios');
const s3 = new AWS.S3();
const crypto = require('crypto');

exports.handler = async (event) => {
    try {
        console.log(`Incoming event: ${JSON.stringify(event)}`);
        const eventBody = JSON.parse(event.body);
        const normalizedHeaders = normalizeObject(event.headers);

        // Validate message signature
        if (!(checkSignature(process.env.GITHUB_SECRET, normalizedHeaders['x-hub-signature-256'], event.body))) {
            console.log('Invalid webhook message signature');
            return responseToApiGw(401, 'Signature is not valid');
        }
        console.log('Signature validated successfully');

        const repoConfig = {
            repoFullName: eventBody.repository.full_name,
            branch: eventBody.ref.split('/')[2],
        };

        // Download the repository package from GitHub Server
        const file = await downloadFile(repoConfig);

        // Upload the repository package to S3 bucket
        const s3Upload = await s3.upload({
            Bucket: process.env.S3BUCKET,
            ServerSideEncryption: 'AES256',
            Key: `${repoConfig.repoFullName}/${repoConfig.branch}.zip`,
            Body: file
        }).promise();
        console.log(s3Upload);

        console.log('Exiting successfully');
        return responseToApiGw(200, 'success');
    }
    catch (err) {
        console.log('Exiting with error', err);
        return responseToApiGw(500, 'Some weird thing happened');
    }
};

/**
 * Convert an object keys to lowercase
 * @param {object} request - this is a object to convert the keys to lowercase
 * @returns {object} - return a new object with keys in lower case
 */
function normalizeObject(inputObject) {
    console.log('info', '>>> normalizeObject()');
    const requestKeys = Object.keys(inputObject);
    let outputObject = {};
    for (let i = 0; i < requestKeys.length; i++) {
        outputObject[requestKeys[i].toLowerCase()] = inputObject[requestKeys[i]];
    }
    console.log('info', '<<< normalizeObject()');
    return outputObject;
}

/**
 * Download the repository content as a zip file
 * @param {object} repoConfig - this is a object containing the config for the repository
 * @returns {stream} - return a stream containing the repository zip file
 */
async function downloadFile(repoConfig) {
    console.log('info', '>>> downloadFile()');
    const params = {
        method: 'get',
        url: `https://github.com/${repoConfig.repoFullName}/archive/refs/heads/${repoConfig.branch}.zip`,
        responseType: 'stream'
    };

    try {
        const resp = await axios.request(params);
        console.log('info', '<<< downloadFile()');
        return resp.data;
    }
    catch (err) {
        console.log('error', err);
        throw new Error(err);
    }
}

/**
 * Check GitHub Server Signature
 * @param {string} signingSecret - this is the signing secret for the GitHub Server webhook
 * @param {string} signature - this is the signatured applied by GitHub to the message
 * @param {object} body - this is the message body
 * @returns {boolean} - return true or false
 */
function checkSignature(signingSecret, signature, body) {
    console.log('info', '>>> signingSecret()');
    const hash = crypto.createHmac('sha256', signingSecret).update(body).digest('hex');

    const signatureHash = signature.split('=');
    if (signatureHash[1] === hash) {
        console.log('info', '<<< signingSecret()');
        return true;
    }
    console.log('info', '<<< signingSecret()');
    return false;
}

/**
 * Generate a response for API Gateway
 * @param {string} statusCode - HTTP status code to return
 * @param {string} detail - this is message detail to return
 * @returns {object} - return the formatted response object
 */
function responseToApiGw(statusCode, detail) {
    if (!statusCode) {
        throw new TypeError('responseToApiGw() expects at least argument statusCode');
    }
    if (statusCode !== '200' && !detail) {
        throw new TypeError('responseToApiGw() expects at least arguments statusCode and detail');
    }

    let body = {};
    if (statusCode === '200' && detail) {
        body = {
            statusCode: statusCode,
            message: detail
        };
    } else if (statusCode === '200' && !detail) {
        body = {
            statusCode: statusCode
        };
    } else {
        body = {
            statusCode: statusCode,
            fault: detail
        };
    }
    let response = {
        statusCode: statusCode,
        body: JSON.stringify(body),
        headers: {
            'Content-Type': 'application/json',
            'Access-Control-Allow-Origin': '*',
            'Access-Control-Allow-Methods': 'POST, GET',
            'Access-Control-Allow-Headers': 'Origin, X-Requested-With, Content-Type, Accept'
        }
    };
    return response;
}